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Al-Osaimi HM, Kanan M, Marghlani L, Al-Rowaili B, Albalawi R, Saad A, Alasmari S, Althobaiti K, Alhulaili Z, Alanzi A, Alqarni R, Alsofiyani R, Shrwani R. A systematic review on malaria and dengue vaccines for the effective management of these mosquito borne diseases: Improving public health. Hum Vaccin Immunother 2024; 20:2337985. [PMID: 38602074 PMCID: PMC11017952 DOI: 10.1080/21645515.2024.2337985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 03/28/2024] [Indexed: 04/12/2024] Open
Abstract
Insect vector-borne diseases (VBDs) pose significant global health challenges, particularly in tropical and subtropical regions. The WHO has launched the "Global Vector Control Response (GVCR) 2017-2030" to address these diseases, emphasizing a comprehensive approach to vector control. This systematic review investigates the potential of malaria and dengue vaccines in controlling mosquito-borne VBDs, aiming to alleviate disease burdens and enhance public health. Following PRISMA 2020 guidelines, the review incorporated 39 new studies out of 934 identified records. It encompasses various studies assessing malaria and dengue vaccines, emphasizing the significance of vaccination as a preventive measure. The findings indicate variations in vaccine efficacy, duration of protection, and safety considerations for each disease, influencing public health strategies. The review underscores the urgent need for vaccines to combat the increasing burden of VBDs like malaria and dengue, advocating for ongoing research and investment in vaccine development.
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Affiliation(s)
- Hind M. Al-Osaimi
- Department of Pharmacy Services Administration, King Fahad Medical City, Riyadh Second Health Cluster, Riyadh, Kingdom of Saudi Arabia
| | - Mohammed Kanan
- Department of Clinical Pharmacy, King Fahad Medical City, Riyadh, Kingdom of Saudi Arabia
| | - Lujain Marghlani
- Department of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Kingdom of Saudi Arabia
| | - Badria Al-Rowaili
- Pharmaceutical Services Department, Northern Area Armed Forces Hospital, King Khalid Military, Hafr Al Batin, Kingdom of Saudi Arabia
| | - Reem Albalawi
- Department of Medicine, Tabuk University, Tabuk, Kingdom of Saudi Arabia
| | - Abrar Saad
- Pharmacy Department, Royal Commission Hospital, Yanbu, Kingdom of Saudi Arabia
| | - Saba Alasmari
- Department of Clinical Pharmacy, King Khalid University, Jeddah, Kingdom of Saudi Arabia
| | - Khaled Althobaiti
- Department of Medicine, Taif University, Ta’if, Kingdom of Saudi Arabia
| | - Zainab Alhulaili
- Department of Clinical Pharmacy, Dammam Medical Complex, Dammam, Kingdom of Saudi Arabia
| | - Abeer Alanzi
- Department of Medicine, King Abdulaziz Hospital, Makkah, Kingdom of Saudi Arabia
| | - Rawan Alqarni
- Department of Medicine and Surgery, King Khalid University, Abha, Kingdom of Saudi Arabia
| | - Razan Alsofiyani
- Department of Medicine, Taif University, Ta’if, Kingdom of Saudi Arabia
| | - Reem Shrwani
- Department of Clinical Pharmacy, Jazan University, Jazan, Kingdom of Saudi Arabia
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Oyibo P, Agbana T, van Lieshout L, Oyibo W, Diehl JC, Vdovine G. An automated slide scanning system for membrane filter imaging in diagnosis of urogenital schistosomiasis. J Microsc 2024; 294:52-61. [PMID: 38291833 DOI: 10.1111/jmi.13269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 01/16/2024] [Accepted: 01/22/2024] [Indexed: 02/01/2024]
Abstract
Traditionally, automated slide scanning involves capturing a rectangular grid of field-of-view (FoV) images which can be stitched together to create whole slide images, while the autofocusing algorithm captures a focal stack of images to determine the best in-focus image. However, these methods can be time-consuming due to the need for X-, Y- and Z-axis movements of the digital microscope while capturing multiple FoV images. In this paper, we propose a solution to minimise these redundancies by presenting an optimal procedure for automated slide scanning of circular membrane filters on a glass slide. We achieve this by following an optimal path in the sample plane, ensuring that only FoVs overlapping the filter membrane are captured. To capture the best in-focus FoV image, we utilise a hill-climbing approach that tracks the peak of the mean of Gaussian gradient of the captured FoVs images along the Z-axis. We implemented this procedure to optimise the efficiency of the Schistoscope, an automated digital microscope developed to diagnose urogenital schistosomiasis by imaging Schistosoma haematobium eggs on 13 or 25 mm membrane filters. Our improved method reduces the automated slide scanning time by 63.18% and 72.52% for the respective filter sizes. This advancement greatly supports the practicality of the Schistoscope in large-scale schistosomiasis monitoring and evaluation programs in endemic regions. This will save time, resources and also accelerate generation of data that is critical in achieving the targets for schistosomiasis elimination.
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Affiliation(s)
- Prosper Oyibo
- Delft Center for Systems and Control, Delft University of Technology, Delft, The Netherlands
| | - Tope Agbana
- Delft Center for Systems and Control, Delft University of Technology, Delft, The Netherlands
| | - Lisette van Lieshout
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Wellington Oyibo
- Centre for Transdisciplinary Research for Malaria & Neglected Tropical Diseases, College of Medicine, University of Lagos, Lagos, Nigeria
| | - Jan-Carel Diehl
- Department of Sustainable Design Engineering, Delft University of Technology, Delft, The Netherlands
| | - Gleb Vdovine
- Delft Center for Systems and Control, Delft University of Technology, Delft, The Netherlands
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Debrah I, Zhong D, Machani MG, Nattoh G, Ochwedo KO, Morang'a CM, Lee MC, Amoah LE, Githeko AK, Afrane YA, Yan G. Non-Coding RNAs Potentially Involved in Pyrethroid Resistance of Anopheles funestus Population in Western Kenya. RESEARCH SQUARE 2024:rs.3.rs-3979432. [PMID: 38464038 PMCID: PMC10925441 DOI: 10.21203/rs.3.rs-3979432/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Backgrounds The resurgence of Anopheles funestus , a dominant vector of human malaria in western Kenya was partly attributed to insecticide resistance. However, evidence on the molecular basis of pyrethroid resistance in western Kenya is limited. Noncoding RNAs (ncRNAs) form a vast class of RNAs that do not code for proteins and are ubiquitous in the insect genome. Here, we demonstrated that multiple ncRNAs could play a potential role in An. funestus resistance to pyrethroid in western Kenya. Materials and Methods Anopheles funestus mosquitoes were sampled by aspiration methods in Bungoma, Teso, Siaya, Port Victoria and Kombewa in western Kenya. The F1 progenies were exposed to deltamethrin (0.05%), permethrin (0.75%), DDT (4%) and pirimiphos-methyl (0.25%) following WHO test guidelines. A synergist assay using piperonyl butoxide (PBO) (4%) was conducted to determine cytochrome P450s' role in pyrethroid resistance. RNA-seq was conducted on a combined pool of specimens that were resistant and unexposed, and the results were compared with those of the FANG susceptible strain. This approach aimed to uncover the molecular mechanisms underlying pyrethroid resistance. Results Pyrethroid resistance was observed in all the sites with an average mortality rate of 57.6%. Port Victoria had the highest level of resistance to permethrin (MR=53%) and deltamethrin (MR=11%) pyrethroids. Teso had the lowest level of resistance to permethrin (MR=70%) and deltamethrin (MR=87%). Resistance to DDT was observed only in Kombewa (MR=89%) and Port Victoria (MR=85%). A full susceptibility to P-methyl (0.25%) was observed in all the sites. PBO synergist assay revealed high susceptibility (>98%) to the pyrethroids in all the sites except for Port Victoria (MR=96%, n=100). Whole transcriptomic analysis showed that most of the gene families associated with pyrethroid resistance comprised non-coding RNAs (67%), followed by imipenemase (10%),cytochrome P450s (6%), cuticular proteins (5%), olfactory proteins (4%), glutathione S-transferases (3%), UDP-glycosyltransferases (2%), ATP-binding cassettes (2%) and carboxylesterases(1%). Conclusions This study unveils the molecular basis of insecticide resistance in An. funestus in western Kenya, highlighting for the first time the potential role of non-coding RNAs in pyrethroid resistance. Targeting non-coding RNAs for intervention development could help in insecticide resistance management.
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Manjurano A, Lyimo E, Kishamawe C, Omolo J, Mosha J, Donald M, Kazyoba P, Kapiga S, Changalucha J. Prevalence of G6PD deficiency and submicroscopic malaria parasites carriage in malaria hotspot area in Northwest, Tanzania. Malar J 2023; 22:372. [PMID: 38062464 PMCID: PMC10704740 DOI: 10.1186/s12936-023-04801-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND The use of primaquine for mass drug administration (MDA) is being considered as a key strategy for malaria elimination. In addition to being the only drug active against the dormant and relapsing forms of Plasmodium vivax, primaquine is the sole potent drug against mature/infectious Plasmodium falciparum gametocytes. It may prevent onward transmission and help contain the spread of artemisinin resistance. However, higher dose of primaquine is associated with the risk of acute haemolytic anaemia in individuals with a deficiency in glucose-6-phosphate dehydrogenase. In many P. falciparum endemic areas there is paucity of information about the distribution of individuals at risk of primaquine-induced haemolysis at higher dose 45 mg of primaquine. METHODS A retrospective cross-sectional study was carried out using archived samples to establish the prevalence of G6PD deficiency in a malaria hotspot area in Misungwi district, located in Mwanza region, Tanzania. Blood samples collected from individuals recruited between August and November 2010 were genotyped for G6PD deficiency and submicroscopic parasites carriage using polymerase chain reaction. RESULTS A total of 263 individuals aged between 0 and 87 were recruited. The overall prevalence of the X-linked G6PD A- mutation was 83.7% (220/263) wild type, 8% (21/263) heterozygous and 8.4% (22/263) homozygous or hemizygous. Although, assessment of the enzymatic activity to assign the phenotypes according to severity and clinical manifestation as per WHO was not carried out, the overall genotype and allele frequency for the G6PD deficiency was 16.4% and 13. 2%, respectively. There was no statistically significant difference in among the different G6PD genotypes (p > 0.05). Out of 248 samples analysed for submicroscopic parasites carriage, 58.1% (144/248) were P. falciparum positive by PCR. G6PD heterozygous deficiency were associated with carriage of submicroscopic P. falciparum (p = 0.029). CONCLUSIONS This study showed that 16.4% of the population in this part of North-western Tanzania carry the G6PD A- mutation, within the range of 15-32% seen in other parts of Africa. G6PD gene mutation is widespread and heterogeneous across the study area where primaquine would be valuable for malaria control and elimination. The maps and population estimates presented here reflect potential risk of higher dose of primaquine being associated with the risk of acute haemolytic anaemia (AHA) in individuals with a deficiency in glucose-6-phosphate dehydrogenase and call further research on mapping of G6PD deficiency in Tanzania. Therefore, screening and education programmes for G6PD deficiency is warranted in a programme of malaria elimination using a higher primaquine dose.
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Affiliation(s)
| | - Eric Lyimo
- Mwanza Centre, National Institute for Medical Research, Mwanza, Tanzania
| | - Coleman Kishamawe
- Mwanza Centre, National Institute for Medical Research, Mwanza, Tanzania
| | - Justin Omolo
- Mabibo Centre, National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Jacklin Mosha
- Mwanza Centre, National Institute for Medical Research, Mwanza, Tanzania
| | - Miyaye Donald
- Mwanza Centre, National Institute for Medical Research, Mwanza, Tanzania
| | - Paul Kazyoba
- Mabibo Centre, National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Saidi Kapiga
- Mwanza Intervention Trials Unit, National Institute for Medical Research, Mwanza, Tanzania
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - John Changalucha
- Mwanza Centre, National Institute for Medical Research, Mwanza, Tanzania
- Mwanza Intervention Trials Unit, National Institute for Medical Research, Mwanza, Tanzania
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N'Guessan R, Camara S, Rowland M, Ahoua Alou LP, Wolie RZ, Zoh MG, N'Guessan B, Tia IZ, Oumbouke WA, Thomas MB, Koffi AA. Attractive targeted sugar bait: the pyrrole insecticide chlorfenapyr and the anti-malarial pharmaceutical artemether-lumefantrine arrest Plasmodium falciparum development inside wild pyrethroid-resistant Anopheles gambiae s.s. mosquitoes. Malar J 2023; 22:344. [PMID: 37946208 PMCID: PMC10636997 DOI: 10.1186/s12936-023-04758-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 10/18/2023] [Indexed: 11/12/2023] Open
Abstract
BACKGROUND Attractive targeted sugar bait (ATSB) is a novel approach to vector control, offering an alternative mode of insecticide delivery via the insect alimentary canal, with potential to deliver a variety of compounds new to medical entomology and malaria control. Its potential to control mosquitoes was recently demonstrated in major field trials in Africa. The pyrrole chlorfenapyr is an insecticide new to malaria vector control, and through its unique mode of action-disruption of ATP mediated energy transfer in mitochondria-it may have direct action on energy transfer in the flight muscle cells of mosquitoes. It may also have potential to disrupt mitochondrial function in malarial parasites co-existing within the infected mosquito. However, little is known about the impact of such compounds on vector competence in mosquitoes responsible for malaria transmission. METHODS In this study, ATSBs containing chlorfenapyr insecticide and, as a positive control, the anti-malarial drugs artemether/lumefantrine (A/L) were compared for their effect on Plasmodium falciparum development in wild pyrethroid-resistant Anopheles gambiae sensu stricto (s.s.) and for their capacity to reduce vector competence. Female mosquitoes were exposed to ATSB containing either sublethal dose of chlorfenapyr (CFP: 0.025%) or concentrations of A/L ranging from 0.4/2.4 mg/ml to 2.4/14.4 mg/ml, either shortly before or after taking infective blood meals. The impact of their component compounds on the prevalence and intensity of P. falciparum infection were compared between treatments. RESULTS Both the prevalence and intensity of infection were significantly reduced in mosquitoes exposed to either A/L or chlorfenapyr, compared to unexposed negative control mosquitoes. The A/L dose (2.4/14.4 mg/ml) totally erased P. falciparum parasites: 0% prevalence of infection in female mosquitoes exposed compared to 62% of infection in negative controls (df = 1, χ2 = 31.23 p < 0.001). The dose of chlorfenapyr (0.025%) that killed < 20% females in ATSB showed a reduction in oocyte density of 95% per midgut (0.18/3.43 per midgut). CONCLUSION These results are evidence that chlorfenapyr, in addition to its direct killing effect on the vector, has the capacity to block Plasmodium transmission by interfering with oocyte development inside pyrethroid-resistant mosquitoes, and through this dual action may potentiate its impact under field conditions.
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Affiliation(s)
- Raphael N'Guessan
- Institut Pierre Richet (IPR), Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire. Raphael.N'
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire. Raphael.N'
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK. Raphael.N'
| | - Soromane Camara
- Institut Pierre Richet (IPR), Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire.
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire.
| | - Mark Rowland
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Ludovic P Ahoua Alou
- Institut Pierre Richet (IPR), Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire
| | - Rosine Z Wolie
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire
- Université Nangui Abrogoua, UFR Des Sciences de la Nature, Abidjan, Côte d'Ivoire
| | - Marius G Zoh
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire
| | - Brou N'Guessan
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire
| | - Innocent Z Tia
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire
| | - Welbeck A Oumbouke
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire
- Innovative Vector Control Consortium, IVCC, Liverpool, UK
| | - Matthew B Thomas
- Department of Entomology & Nematology, The University of Florida, Gainesville, FL, USA
| | - Alphonsine A Koffi
- Institut Pierre Richet (IPR), Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire
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Ssentongo P, Chinchilli VM, Shah K, Harbaugh T, Ba DM. Factors associated with pediatric febrile illnesses in 27 countries of Sub-Saharan Africa. BMC Infect Dis 2023; 23:391. [PMID: 37308809 DOI: 10.1186/s12879-023-08350-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 05/24/2023] [Indexed: 06/14/2023] Open
Abstract
BACKGROUND Evidence on the relative importance of various factors associated with febrile illness in children and their heterogeneity across countries can inform the prevention, identification, and management of communicable diseases in resource-limited countries. The objective of the study is to assess the relative significance of factors associated with childhood febrile illness in 27 sub-Saharan African countries. METHODS This cross-sectional study of 298,327 children aged 0 to 59 months assessed the strengths of associations of 18 factors with childhood fevers, using Demographic and Health Surveys (2010-2018) from 27 sub-Saharan African countries. A total of 7 child level factors (i.e., respiratory illness, diarrhea, breastfeeding initiation; vitamin A supplements; child's age; full vaccination; sex), 5 maternal factors (maternal education; maternal unemployment; antenatal care; maternal age, and maternal marriage status) and 6 household factors (household wealth; water source; indoor pollution, stool disposal; family planning needs and rural residence) were assessed. Febrile illness was defined as the presence of fever in 2 weeks preceding the survey. RESULTS Among the 298,327 children aged 0 to 59 months included in the analysis, the weighted prevalence of fever was 22.65% (95% CI, 22.31%-22.91%). In the pooled sample, respiratory illness was the strongest factor associated with fever in children (adjusted odds ratio [aOR], 5.46; 95% CI, 5.26-5.67; P < .0001), followed by diarrhea (aOR, 2.96; 95% CI, 2.85-3.08; P < .0001), poorest households (aOR, 1.33; 95% CI,1.23-1.44; P < .0001), lack of maternal education (aOR, 1.25; 95% CI, 1.10-1.41; P < .0001), and delayed breastfeeding (aOR, 1.18; 95% CI, 1.14-1.22; P < .0001. Febrile illnesses were more prevalent in children older than >6 months compared to those 6 months and younger. Unsafe water, unsafe stool disposal, and indoor pollution were not associated with child fever in the pooled analysis but had a large country-level heterogeneity. CONCLUSIONS Major causes of fevers in sub-Saharan Africa could be attributed to respiratory infections and possibly viral infections, which should not be treated by antimalarial drugs or antibiotics. Point-of-care diagnostics are needed to identify the pathogenic causes of respiratory infections to guide the clinical management of fevers in limited-resource countries.
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Affiliation(s)
- Paddy Ssentongo
- Department of Medicine, Penn State Milton S. Hershey Medical Center, Hershey, PA, 17033, USA.
- Department of Public Health Sciences, Penn State College of Medicine, 500 University Drive, Hershey, PA, 17033, USA.
| | - Vernon M Chinchilli
- Department of Public Health Sciences, Penn State College of Medicine, 500 University Drive, Hershey, PA, 17033, USA
| | - Khush Shah
- Department of Biology, Millersville University, Millersville, PA, USA
| | - Thaddeus Harbaugh
- Department of Public Health Sciences, Penn State College of Medicine, 500 University Drive, Hershey, PA, 17033, USA
| | - Djibril M Ba
- Department of Public Health Sciences, Penn State College of Medicine, 500 University Drive, Hershey, PA, 17033, USA
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Hollowell T, Sewe MO, Rocklöv J, Obor D, Odhiambo F, Ahlm C. Public health determinants of child malaria mortality: a surveillance study within Siaya County, Western Kenya. Malar J 2023; 22:65. [PMID: 36823600 PMCID: PMC9948786 DOI: 10.1186/s12936-023-04502-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/18/2023] [Indexed: 02/25/2023] Open
Abstract
BACKGROUND Malaria deaths among children have been declining worldwide during the last two decades. Despite preventive, epidemiologic and therapy-development work, mortality rate decline has stagnated in western Kenya resulting in persistently high child malaria morbidity and mortality. The aim of this study was to identify public health determinants influencing the high burden of malaria deaths among children in this region. METHODS A total of 221,929 children, 111,488 females and 110,441 males, under the age of 5 years were enrolled in the Kenya Medical Research Institute/Center for Disease Control Health and Demographic Surveillance System (KEMRI/CDC HDSS) study area in Siaya County during the period 2003-2013. Cause of death was determined by use of verbal autopsy. Age-specific mortality rates were computed, and cox proportional hazard regression was used to model time to malaria death controlling for the socio-demographic factors. A variety of demographic, social and epidemiologic factors were examined. RESULTS In total 8,696 (3.9%) children died during the study period. Malaria was the most prevalent cause of death and constituted 33.2% of all causes of death, followed by acute respiratory infections (26.7%) and HIV/AIDS related deaths (18.6%). There was a marked decrease in overall mortality rate from 2003 to 2013, except for a spike in the rates in 2008. The hazard of death differed between age groups with the youngest having the highest hazard of death HR 6.07 (95% CI 5.10-7.22). Overall, the risk attenuated with age and mortality risks were limited beyond 4 years of age. Longer distance to healthcare HR of 1.44 (95% CI 1.29-1.60), l ow maternal education HR 3.91 (95% CI 1.86-8.22), and low socioeconomic status HR 1.44 (95% CI 1.26-1.64) were all significantly associated with increased hazard of malaria death among children. CONCLUSIONS While child mortality due to malaria in the study area in Western Kenya, has been decreasing, a final step toward significant risk reduction is yet to be accomplished. This study highlights residual proximal determinants of risk which can further inform preventive actions.
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Affiliation(s)
- Thomas Hollowell
- Department of Clinical Microbiology, Infection and Immunology, Umeå University, Umeå, Sweden. .,Department of Infectious Diseases, Karlstad Central Hospital, Region Värmland, Karlstad, Sweden.
| | - Maquins Odhiambo Sewe
- grid.33058.3d0000 0001 0155 5938KEMRI Centre for Global Health Research, Kisumu, Kenya ,grid.12650.300000 0001 1034 3451Department of Public Health and Clinical Medicine, Section of Sustainable Health, Umeå University, Umeå, Sweden
| | - Joacim Rocklöv
- grid.12650.300000 0001 1034 3451Department of Public Health and Clinical Medicine, Section of Sustainable Health, Umeå University, Umeå, Sweden ,grid.7700.00000 0001 2190 4373Heidelberg Institute of Global Health and Interdisciplinary Center for Scientific Computing, University of Heidelberg, Heidelberg, Germany
| | - David Obor
- grid.33058.3d0000 0001 0155 5938KEMRI Centre for Global Health Research, Kisumu, Kenya
| | - Frank Odhiambo
- grid.33058.3d0000 0001 0155 5938KEMRI Centre for Global Health Research, Kisumu, Kenya
| | - Clas Ahlm
- grid.12650.300000 0001 1034 3451Department of Clinical Microbiology, Infection and Immunology, Umeå University, Umeå, Sweden
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Malaria profile and socioeconomic predictors among under-five children: an analysis of 11 sub-Saharan African countries. Malar J 2023; 22:55. [PMID: 36788541 PMCID: PMC9927033 DOI: 10.1186/s12936-023-04484-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 02/10/2023] [Indexed: 02/16/2023] Open
Abstract
BACKGROUND African region accounts for 95% of all malaria cases and 96% of malaria deaths with under-five children accounting for 80% of all deaths in the region. This study assessed the socioeconomic determinants of malaria prevalence and provide evidence on the socioeconomic profile of malaria infection among under-five children in 11 SSA countries. METHODS This study used data from the 2010 to 2020 Demographic and Health Survey (DHS). The survey used a two-stage stratified-cluster sampling design based on the sampling frame of the population and housing census of countries included. Statistical analyses relied on Pearson's χ2, using the CHAID decision-tree algorithm and logistic regression implemented in R V.4.6. RESULTS Of 8547 children considered, 24.2% (95% confidence interval CI 23.4-25.05%) had malaria infection. Also, the prevalence of malaria infection seems to increase with age. The following variables are statistically associated with the prevalence of malaria infection among under-five children: under-five child's age, maternal education, sex of household head, household wealth index, place of residence, and African region where mother-child pair lives. Children whose mothers have secondary education have about 56% lower risk (odds ratio = 0.44; 95% CI 0.40-0.48) of malaria infection and 73% lower (odds ratio = 0.37; 95% CI 0.32-0.43) among children living in the richest households, compared to children living in the poorest households. CONCLUSIONS The findings of this study provide unique insights on how socioeconomic and demographic variables, especially maternal education level significantly predicts under-five malaria prevalence across the SSA region. Therefore, ensuring that malaria interventions are underpinned by a multisectoral approach that comprehensively tackles the interplay of maternal education and other socioeconomic variables will be critical in attaining malaria prevention and control targets in SSA.
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Epidémiology of malaria from 2019 to 2021 in the southeastern city of Franceville, Gabon. BMC Public Health 2022; 22:2313. [PMID: 36496354 PMCID: PMC9739344 DOI: 10.1186/s12889-022-14765-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 11/29/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND In Gabon, a new national malaria control policy was implemented in 2003. It resulted in a decrease in the number of malaria cases in the country. In March 2020, the disruption of routine health services due to the COVID-19 pandemic has led to an increase in cases and deaths due to malaria. However, in Franceville, south-east Gabon, no data on malaria cases recorded before, during and after the COVID-19 epidemic has been published. Thus, the objective of this study was to determine the epidemiological characteristics of malaria in Franceville from 2019 to 2021. METHODS A retrospectively study of malaria cases was performed at the Hôpital de l'Amitié Sino-Gabonaise (HASG). Information regarding age, gender, malaria diagnosis by microscopy and hematology cell count were collected from laboratory registers from June 2019 to December 2021. Malaria data were analyzed and correlated with seasonal variations. RESULTS The data of 12,695 febrile patients were collected from the laboratory registers of the HASG, among which 4252 (33.5%) patients were found positive for malaria. The malaria prevalence was 37.5% in 2020 year. This prevalence was highest compared to the 2019 (29.6%) and 2021 (31.5%) year (p < 0.001). During the short rainy season (October to December), a large increase in malaria cases was observed all three year, from 2019 to 2021 (p > 0.05). CONCLUSION The prevalence of malaria in Franceville was very high during COVID-19 pandemic. It is therefore necessary to strengthen existing interventions and implement more effective interventions.
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Achee NL, Perkins TA, Moore SM, Liu F, Sagara I, Van Hulle S, Ochomo EO, Gimnig JE, Tissera HA, Harvey SA, Monroe A, Morrison AC, Scott TW, Reiner RC, Grieco JP. Spatial repellents: The current roadmap to global recommendation of spatial repellents for public health use. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2022; 3:100107. [PMID: 36590345 PMCID: PMC9801085 DOI: 10.1016/j.crpvbd.2022.100107] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 11/18/2022] [Accepted: 12/04/2022] [Indexed: 12/13/2022]
Abstract
Spatial repellent (SR) products are envisioned to complement existing vector control methods through the continual release of volatile active ingredients (AI) providing: (i) protection against day-time and early-evening biting; (ii) protection in enclosed/semi-enclosed and peri-domestic spaces; (iii) various formulations to fit context-specific applications; and (iv) increased coverage over traditional control methods. SR product AIs also have demonstrated effect against insecticide-resistant vectors linked to malaria and Aedes-borne virus (ABV) transmission. Over the past two decades, key stakeholders, including World Health Organization (WHO) representatives, have met to discuss the role of SRs in reducing arthropod-borne diseases based on existing evidence. A key focus has been to establish a critical development path for SRs, including scientific, regulatory and social parameters that would constitute an outline for a SR target product profile, i.e. optimum product characteristics. The principal gap is the lack of epidemiological data demonstrating SR public health impact across a range of different ecological and epidemiological settings, to inform a WHO policy recommendation. Here we describe in brief trials that are designed to fulfill evidence needs for WHO assessment and initial projections of SR cost-effectiveness against malaria and dengue.
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Affiliation(s)
- Nicole L. Achee
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA,Corresponding author. Department of Biological Sciences, Eck Institute for Global Health, 239 Galvin Life Science Center, Notre Dame, IN, 46556, USA.
| | - T. Alex Perkins
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Sean M. Moore
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Fang Liu
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN, USA
| | - Issaka Sagara
- Malaria Research and Training Center (MRTC), Faculty of Medicine, Dentistry and Pharmacy at the University of Sciences, Techniques and Technologies of Bamako (USTTB), Bamako, Mali
| | | | - Eric O. Ochomo
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - John E. Gimnig
- Centers for Disease Control and Prevention, Division of Parasitic Diseases and Malaria, Atlanta, GA, USA
| | | | - Steven A. Harvey
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - April Monroe
- Johns Hopkins Center for Communication Programs, Baltimore, MD, USA
| | - Amy C. Morrison
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Thomas W. Scott
- Department of Entomology and Nematology, University of California, Davis, CA, USA
| | - Robert C. Reiner
- Department of Health Metrics Sciences, University of Washington, Seattle, WA, USA
| | - John P. Grieco
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
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11
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Hodson DZ, Mbarga Etoundi Y, Mbatou Nghokeng N, Mohamadou Poulibe R, Magne Djoko S, Goodwin J, Cheteug Nguesta G, Nganso T, Armstrong JN, Andrews JJ, Zhang E, Wade M, Eboumbou Moukoko CE, Boum Y, Parikh S. Clinical characteristics of Plasmodium falciparum infection among symptomatic patients presenting to a major urban military hospital in Cameroon. Malar J 2022; 21:298. [PMID: 36273147 PMCID: PMC9588226 DOI: 10.1186/s12936-022-04315-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 10/10/2022] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Urban malaria has received insufficient attention in the literature. The prevalence and clinical characteristics of Plasmodium falciparum infection amongst patients presenting with suspected malaria were investigated at a major urban hospital in Douala, Cameroon with a particular focus on anaemia. METHODS A cross-sectional, 18-week demographic and clinical survey was conducted of patients presenting to the Emergency Department of Douala Military Hospital with suspected malaria, largely defined by the presence or recent history of fever. Venous samples were tested for P. falciparum using rapid diagnostic tests and PCR, and anaemia was defined by haemoglobin level according to WHO definitions. Likelihood ratios (LR), odds ratios (OR), and population attributable risk percent (PARP) were calculated. RESULTS Participants were ages 8 months to 86 years, 51% were women (257/503), and all districts of Douala were represented. Overall, 38.0% (n = 189/497) were anaemic, including 5.2% (n = 26/497) with severe anaemia. Anaemia prevalence was significantly higher (OR: 2.20, 95% CI 1.41-3.45) among children < 15 years (53.1%, n = 52/98) compared to adults (34%, n = 133/392). Plasmodium falciparum was detected in 37.2% by nested PCR. Among all participants, several factors were associated with clinically significant LR for P. falciparum infection, including age 10-14 years (positive LR: 3.73), living in the island district of Douala VI (positive LR: 3.41), travel to any of three northern regions (positive LR: 5.11), and high fever > 40 °C at presentation (positive LR: 4.83). Among all participants, 8.7% of anaemia was associated with P. falciparum infection, while the PARP was 33.2% among those < 15 years of age and 81.0% among 10-14-year-olds. CONCLUSIONS The prevalence of P. falciparum infection in the urban hospital was high. Mirroring trends in many rural African settings, older children had the highest positivity rate for P. falciparum infection. Anaemia was also common in all age groups, and for those 10-14 years of age, 80% of the risk for anaemia was associated with P. falciparum infection. Malaria rates in major urban population centres can be high, and more research into the multifactorial causes of anaemia across the age spectrum are needed.
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Affiliation(s)
| | - Yannick Mbarga Etoundi
- Douala Military Hospital, Douala, Cameroon
- Douala Military Hospital School of Nursing, Douala, Cameroon
- Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
| | | | | | | | - Justin Goodwin
- Yale School of Medicine, New Haven, USA
- Yale School of Public Health, New Haven, USA
| | - Glwadys Cheteug Nguesta
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Malaria Research Service, Centre Pasteur of Cameroon, Yaoundé, Cameroon
| | - Tatiana Nganso
- Malaria Research Service, Centre Pasteur of Cameroon, Yaoundé, Cameroon
| | | | | | | | | | - Carole Else Eboumbou Moukoko
- Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
- Malaria Research Service, Centre Pasteur of Cameroon, Yaoundé, Cameroon
| | - Yap Boum
- Epicentre, Yaoundé, Cameroon
- Faculty of Medicine and Biomedical Sciences, University of Yaoundé, Yaoundé, Cameroon
| | - Sunil Parikh
- Yale School of Medicine, New Haven, USA.
- Yale School of Public Health, New Haven, USA.
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12
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Musiba RM, Tarimo BB, Monroe A, Msaky D, Ngowo H, Mihayo K, Limwagu A, Chilla GT, Shubis GK, Ibrahim A, Greer G, Mcha JH, Haji KA, Abbas FB, Ali A, Okumu FO, Kiware SS. Outdoor biting and pyrethroid resistance as potential drivers of persistent malaria transmission in Zanzibar. Malar J 2022; 21:172. [PMID: 35672768 PMCID: PMC9171934 DOI: 10.1186/s12936-022-04200-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 05/24/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Low-level of malaria transmission persist in Zanzibar despite high coverage of core vector control interventions. This study was carried out in hot-spot sites to better understand entomological factors that may contribute to residual malaria transmission in Zanzibar. METHODS A total of 135 households were randomly selected from six sites and consented to participate with 20-25 households per site. Mosquito vector surveillance was carried out indoors and outdoors from 6:00 pm-7:00 am using miniaturized double net trap (DN-Mini™). Additional collections were done indoors using mouth aspirators to retrieve resting mosquitoes from wall and ceiling surfaces, and outdoors using resting bucket and pit traps. All collected mosquitoes were morphologically and genetically (PCR) analysed in the laboratory. All collected anopheline and blood-fed mosquitoes were analysed for sporozoite infection and blood meal host preferences by Circumsporozoite Protein ELISA and blood meal ELISA, respectively. The differences between indoor and outdoor mosquito biting rates were analysed using generalized linear mixed models. Levels of resistance to commonly used insecticides were quantified by WHO susceptibility tests. RESULTS Out of 704 malaria vectors collected across 135 households, PCR analysis shows that 98.60% were Anopheles arabiensis, 0.6% Anopheles merus and 0.6% Anopheles gambiae sensu stricto. Sporozoite ELISA analysis indicates that all mosquitoes were negative for the malaria parasite. The results show that more An. arabiensis were collected outdoor (~ 85%) compared to indoor (~ 15%). Furthermore, large numbers of An. arabiensis were caught in outdoor resting sites, where the pit trap (67.2%) collected more mosquitoes compared to the outdoor DN-Mini trap (32.8%). Nearly two-thirds (60.7%) of blood-fed mosquitoes had obtained blood meals from non-human hosts. Mosquitoes displayed non-uniform susceptibility status and resistance intensity among the tested insecticides across the study sites to all WHO recommended insecticides across the study sites. CONCLUSION This study suggests that in contexts such as Zanzibar, testing of novel techniques to complement indoor protection and targeting outdoor biting and/or resting mosquitoes, may be warranted to complement existing interventions and contribute to malaria elimination efforts. The study highlights the need to implement novel interventions and/or adaptations of strategies that can target outdoors biting mosquitoes.
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Affiliation(s)
| | | | - April Monroe
- PMI VectorWorks Project, Johns Hopkins Center for Communication Programs, Baltimore, MD, USA
| | | | - Halfan Ngowo
- Ifakara Health Institute, Dar es Salaam, Tanzania
| | | | - Alex Limwagu
- Ifakara Health Institute, Dar es Salaam, Tanzania
| | | | | | | | - George Greer
- US President's Malaria Initiative, U.S. Agency for International Development, Dar es Salaam, Tanzania
| | - Juma H Mcha
- Zanzibar Malaria Elimination Programme, Zanzibar, Tanzania
| | - Khamis A Haji
- Zanzibar Malaria Elimination Programme, Zanzibar, Tanzania
| | - Faiza B Abbas
- Zanzibar Malaria Elimination Programme, Zanzibar, Tanzania
| | - Abdullah Ali
- Zanzibar Malaria Elimination Programme, Zanzibar, Tanzania
| | | | - Samson S Kiware
- Ifakara Health Institute, Dar es Salaam, Tanzania
- Pan African Mosquito Control Association (PAMCA), Nairobi, Kenya
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13
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Guinovart C, Sigaúque B, Bassat Q, Loscertales MP, Nhampossa T, Acácio S, Machevo S, Maculuve S, Bambo G, Mucavele H, Soriano-Gabarró M, Saifodine A, Nhacolo A, Nhalungo D, Sacoor C, Saúte F, Aponte JJ, Menéndez C, Macete E, Alonso PL. The epidemiology of severe malaria at Manhiça District Hospital, Mozambique: a retrospective analysis of 20 years of malaria admissions surveillance data. THE LANCET GLOBAL HEALTH 2022; 10:e873-e881. [DOI: 10.1016/s2214-109x(22)00125-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 03/03/2022] [Accepted: 03/17/2022] [Indexed: 11/28/2022] Open
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14
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Forsyth JE, Kempinsky A, Pitchik HO, Alberts CJ, Mutuku FM, Kibe L, Ardoin NM, LaBeaud AD. Larval source reduction with a purpose: Designing and evaluating a household- and school-based intervention in coastal Kenya. PLoS Negl Trop Dis 2022; 16:e0010199. [PMID: 35363780 PMCID: PMC9007363 DOI: 10.1371/journal.pntd.0010199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 04/13/2022] [Accepted: 01/25/2022] [Indexed: 11/18/2022] Open
Abstract
Background Since Aedes aegypti mosquitoes preferentially breed in domestic containers, control efforts focus on larval source reduction. Our objectives were to design and test the effectiveness of a source reduction intervention to improve caregiver knowledge and behaviors in coastal Kenya. Methodology/Principal findings We conducted a cluster-randomized controlled trial with 261 households from 5 control villages and 259 households from 5 intervention villages. From each household, one child (10–16 years old) and his or her primary caregiver participated in the intervention. We assessed caregiver knowledge and behavior at baseline, as well as 3 and 12 months after the intervention. We assessed household entomological indices at baseline and 12 months after the intervention to avoid seasonal interference. We conducted qualitative interviews with 34 caregivers to understand barriers and facilitators to change. We counted and weighed containers collected by children and parents during a community container clean-up and recycling event. After 12 months, caregiver knowledge about and self-reported behavior related to at least one source reduction technique was more than 50 percentage points higher in the intervention compared to control arm (adjusted risk differences for knowledge: 0.69, 95% CI [0.56 to 0.82], and behavior: 0.58 [0.43 to 0.73]). Respondents stated that other family members’ actions were the primary barriers to proper container management. The number of containers at households did not differ significantly across arms even though children and parents collected 17,200 containers (1 ton of plastics) which were used to planted 4,000 native trees as part of the community event. Conclusions/Significance Our study demonstrates that source reduction interventions can be effective if designed with an understanding of the social and entomological context. Further, source reduction is not an individual issue, but rather a social/communal issue, requiring the participation of other household and community members to be sustained. The disease burden of arboviruses transmitted by Aedes aegypti mosquitoes remains high globally. Since these mosquitoes are day-biters, bed nets are not effective at preventing mosquito bites. Additionally, because Ae. aegypti preferentially breed in domestic containers, control efforts focus on reducing containers for mosquito breeding (source reduction). We developed and evaluated a household- and school-based intervention to improve knowledge and behaviors related to source reduction. We assessed caregiver knowledge and behavior before the intervention and after 3 and 12 months. Subsequently, we conducted qualitative interviews among a sub-set of participants to understand why they did or did not change their behavior. We also assessed mosquito-related indices: the number of breeding containers and immature mosquito abundance before and 12 months after the intervention. We found that those receiving the intervention had more knowledge and self-reported behavior change than those who did not. Nonetheless, the intervention had no effect on mosquito nor containers abundance. In a multi-person household, all household members need to be committed to change, not just the caregiver and child. Our study highlights how mosquito control is not an individual issue, but one that needs the participation of a sufficient majority of household and community members to ensure effectiveness.
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Affiliation(s)
- Jenna E. Forsyth
- Stanford Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
- * E-mail:
| | - Arielle Kempinsky
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Helen O. Pitchik
- Division of Epidemiology, School of Public Health, University of California, Berkeley, California, United States of America
| | - Catharina J. Alberts
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
| | | | - Lydiah Kibe
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya
| | - Nicole M. Ardoin
- Stanford Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
| | - A. Desiree LaBeaud
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
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15
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Alene KA, Elagali A, Barth DD, Rumisha SF, Amratia P, Weiss DJ, Atalell KA, Erena AK, Gething PW, Clements ACA. Spatial codistribution of HIV, tuberculosis and malaria in Ethiopia. BMJ Glob Health 2022; 7:bmjgh-2021-007599. [PMID: 35217531 PMCID: PMC8867247 DOI: 10.1136/bmjgh-2021-007599] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 01/20/2022] [Indexed: 12/15/2022] Open
Abstract
Background HIV, tuberculosis (TB) and malaria are the three most important infectious diseases in Ethiopia, and sub-Saharan Africa. Understanding the spatial codistribution of these diseases is critical for designing geographically targeted and integrated disease control programmes. This study investigated the spatial overlap and drivers of HIV, TB and malaria prevalence in Ethiopia. Methods HIV, TB and malaria data were obtained from different nationwide prevalence surveys, and geospatial covariates were obtained from publicly available sources. A Bayesian model-based geostatistical framework was applied to each survey leveraging the strength of high-resolution spatial covariates to predict continuous disease-specific prevalence surfaces and their codistribution. Results The national prevalence was 1.54% (95% CI 1.40 to 1.70) for HIV, 0.39% (95% CI 0.34 to 0.45) for TB and 1.1% (95%CI 0.95 to 1.32) for malaria. Substantial subnational variation was predicted with the highest HIV prevalence estimated in Gambela (4.52%), Addis Ababa (3.52%) and Dire Dawa (2.67%) regions. TB prevalence was highest in Dire Dawa (0.96%) and Gambela (0.88%), while malaria was highest in Gambela (6.1%) and Benishangul-Gumuz (3.8%). Spatial overlap of their prevalence was observed in some parts of the country, mainly Gambela region. Spatial distribution of the diseases was significantly associated with healthcare access, demographic, and climatic factors. Conclusions The national distribution of HIV, TB and malaria was highly focal in Ethiopia, with substantial variation at subnational and local levels. Spatial distribution of the diseases was significantly associated with healthcare access, demographic and climatic factors. Spatial overlap of HIV, TB and malaria prevalence was observed in some parts of the country. Integrated control programmes for these diseases should be targeted to these areas with high levels of co-endemicity.
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Affiliation(s)
- Kefyalew Addis Alene
- Geospatial Health and Development, Telethon Kids Institute, Nedlands, Western Australia, Australia .,Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia
| | - Ahmed Elagali
- Geospatial Health and Development, Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Dylan D Barth
- University of Western Australia, Perth, Western Australia, Australia.,Wesfarmers Centre for Vaccines and Infectious Diseases, Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Susan F Rumisha
- Geospatial Health and Development, Telethon Kids Institute, Nedlands, Western Australia, Australia.,National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Punam Amratia
- Geospatial Health and Development, Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Daniel J Weiss
- Geospatial Health and Development, Telethon Kids Institute, Nedlands, Western Australia, Australia.,Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia
| | - Kendalem Asmare Atalell
- School of Nursing, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
| | | | - Peter W Gething
- Geospatial Health and Development, Telethon Kids Institute, Nedlands, Western Australia, Australia.,Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia
| | - Archie C A Clements
- Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia
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16
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Mark-release-recapture experiment in Burkina Faso demonstrates reduced fitness and dispersal of genetically-modified sterile malaria mosquitoes. Nat Commun 2022; 13:796. [PMID: 35145082 PMCID: PMC8831579 DOI: 10.1038/s41467-022-28419-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 01/12/2022] [Indexed: 11/15/2022] Open
Abstract
Every year, malaria kills approximately 405,000 people in Sub-Saharan Africa, most of them children under the age of five years. In many countries, progress in malaria control has been threatened by the rapid spread of resistance to antimalarial drugs and insecticides. Novel genetic mosquito control approaches could play an important role in future integrated malaria control strategies. In July 2019, the Target Malaria consortium proceeded with the first release of hemizygous genetically-modified (GM) sterile and non-transgenic sibling males of the malaria mosquito Anopheles coluzzii in Burkina Faso. This study aimed to determine the potential fitness cost associated to the transgene and gather important information related to the dynamic of transgene-carrying mosquitoes, crucial for next development steps. Bayesian estimations confirmed that GM males had lower survival and were less mobile than their wild type (WT) siblings. The estimated male population size in Bana village, at the time of the release was 28,000 - 37,000. These results provide unique information about the fitness and behaviour of released GM males that will inform future releases of more effective strains of the A. gambiae complex. Release of genetically-modified sterile mosquitoes is a potential method of malaria control but has yet to be tested in the field. Here, the authors perform a mark-release-recapture experiment and show that genetically-modified mosquitoes have reduced survival and dispersal compared to wild-types.
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17
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Evaluation of prediction models for the malaria incidence in Marodijeh Region, Somaliland. J Parasit Dis 2021; 46:395-408. [DOI: 10.1007/s12639-021-01458-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/30/2021] [Indexed: 10/19/2022] Open
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18
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Mairet-Khedim M, Nsango S, Ngou C, Menard S, Roesch C, Khim N, Srun S, Iriart X, Lanot T, Otam L, Abega F, Ayong L, Morlais I, Gandia P, Witkowski B, Berry A. Efficacy of dihydroartemisinin/piperaquine in patients with non-complicated Plasmodium falciparum malaria in Yaoundé, Cameroon. J Antimicrob Chemother 2021; 76:3037-3044. [PMID: 34453535 DOI: 10.1093/jac/dkab281] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/12/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Dihydroartemisinin/piperaquine is increasingly used for the treatment of uncomplicated Plasmodium falciparum malaria in Africa. The efficacy of this combination in Cameroon is poorly documented, while resistance to dihydroartemisinin/piperaquine readily spreads in Southeast Asia. OBJECTIVES This study evaluated the clinical efficacy of dihydroartemisinin/piperaquine in Cameroon, as well as the molecular profile and phenotypic susceptibility of collected isolates to dihydroartemisinin and piperaquine. PATIENTS AND METHODS Dihydroartemisinin/piperaquine efficacy in 42 days was followed-up for 138 patients presenting non-complicated falciparum malaria. Piperaquine concentration was determined at day 7 for 124 patients. kelch13 gene polymorphisms (n = 150) and plasmepsin2 gene amplification (n = 148) were determined as molecular markers of resistance to dihydroartemisinin and piperaquine, respectively. Parasite susceptibility to dihydroartemisinin and piperaquine was determined using validated in vitro survival assays. RESULTS The efficacy of dihydroartemisinin/piperaquine treatment was 100% after PCR correction. The reinfections were not associated with a variation of piperaquine concentration at day 7. Ninety-six percent (144/150) of the samples presented a WT allele of the kelch13 gene. Two percent (3/150) presented the non-synonymous mutation A578S, which is not associated with resistance to dihydroartemisinin. No duplication of the plasmepsin2 gene was observed (0/148). All the samples tested in vitro by survival assays (n = 87) were susceptible to dihydroartemisinin and piperaquine. CONCLUSIONS Dihydroartemisinin/piperaquine has demonstrated excellent therapeutic efficacy with no evidence of emerging artemisinin or piperaquine resistance in Yaoundé, Cameroon. This observation suggests that dihydroartemisinin/piperaquine could be a sustainable therapeutic solution for P. falciparum malaria if implemented in areas previously free of artemisinin- and piperaquine-resistant parasites, unlike Southeast Asia.
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Affiliation(s)
- Mélissa Mairet-Khedim
- Malaria Translational Research Unit, Pasteur International Unit, Pasteur International Network, Phnom Penh, Cambodia and Paris, France.,Institut Toulousain des Maladies Infectieuses et Inflammatoires (Infinity), Université Toulouse, CNRS UMR5051, INSERM UMR1291, UPS, Toulouse, France.,Structural Microbiology Unit, Institut Pasteur, CNRS UMR 3528, 25 rue du Docteur Roux, 75724 Paris 15, France
| | - Sandrine Nsango
- Department of Biological Sciences, Faculté de Médecine et des Sciences Pharmaceutiques, Université de Douala, Douala, Cameroon.,Malaria Research Unit, Centre Pasteur du Cameroon, Yaoundé, Cameroon
| | - Christelle Ngou
- Malaria Research Unit, Centre Pasteur du Cameroon, Yaoundé, Cameroon.,MIVEGEC, IRD, CNRS, Univ. Montpellier, Montpellier, France
| | - Sandie Menard
- Institut Toulousain des Maladies Infectieuses et Inflammatoires (Infinity), Université Toulouse, CNRS UMR5051, INSERM UMR1291, UPS, Toulouse, France
| | - Camille Roesch
- Malaria Translational Research Unit, Pasteur International Unit, Pasteur International Network, Phnom Penh, Cambodia and Paris, France.,Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Nimol Khim
- Malaria Translational Research Unit, Pasteur International Unit, Pasteur International Network, Phnom Penh, Cambodia and Paris, France.,Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Sreynet Srun
- Malaria Translational Research Unit, Pasteur International Unit, Pasteur International Network, Phnom Penh, Cambodia and Paris, France.,Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Xavier Iriart
- Institut Toulousain des Maladies Infectieuses et Inflammatoires (Infinity), Université Toulouse, CNRS UMR5051, INSERM UMR1291, UPS, Toulouse, France.,Service de Parasitologie-Mycologie, Centre Hospitalier Universitaire de Toulouse, Hôpital Purpan, Toulouse F-31300, France
| | - Thomas Lanot
- Laboratoire de Pharmacocinétique et Toxicologie, Centre Hospitalier Universitaire de Toulouse, Hôpital Purpan, Toulouse F-31300, France
| | - Laure Otam
- Institut Toulousain des Maladies Infectieuses et Inflammatoires (Infinity), Université Toulouse, CNRS UMR5051, INSERM UMR1291, UPS, Toulouse, France.,Département des Sciences Biomédicales, Faculté des Sciences, Université de Ngaoundéré, Ngaoundéré, Cameroon
| | | | - Lawrence Ayong
- Malaria Research Unit, Centre Pasteur du Cameroon, Yaoundé, Cameroon
| | | | - Peggy Gandia
- Laboratoire de Pharmacocinétique et Toxicologie, Centre Hospitalier Universitaire de Toulouse, Hôpital Purpan, Toulouse F-31300, France.,INTHERES, Université de Toulouse, INRA, ENVT, BP 87614, 31076 Toulouse Cedex 3, France
| | - Benoit Witkowski
- Malaria Translational Research Unit, Pasteur International Unit, Pasteur International Network, Phnom Penh, Cambodia and Paris, France.,Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Antoine Berry
- Institut Toulousain des Maladies Infectieuses et Inflammatoires (Infinity), Université Toulouse, CNRS UMR5051, INSERM UMR1291, UPS, Toulouse, France.,Service de Parasitologie-Mycologie, Centre Hospitalier Universitaire de Toulouse, Hôpital Purpan, Toulouse F-31300, France
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Cai J, Chen S, Zhu F, Lu X, Liu T, Xu W. Whole-Killed Blood-Stage Vaccine: Is It Worthwhile to Further Develop It to Control Malaria? Front Microbiol 2021; 12:670775. [PMID: 33995336 PMCID: PMC8119638 DOI: 10.3389/fmicb.2021.670775] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/08/2021] [Indexed: 01/09/2023] Open
Abstract
Major challenges have been encountered regarding the development of highly efficient subunit malaria vaccines, and so whole-parasite vaccines have regained attention in recent years. The whole-killed blood-stage vaccine (WKV) is advantageous as it can be easily manufactured and efficiently induced protective immunity against a blood-stage challenge, as well as inducing cross-stage protection against both the liver and sexual-stages. However, it necessitates a high dose of parasitized red blood cell (pRBC) lysate for immunization, and this raises concerns regarding its safety and low immunogenicity. Knowledge of the major components of WKV that can induce or evade the host immune response, and the development of appropriate human-compatible adjuvants will greatly help to optimize the WKV. Therefore, we argue that the further development of the WKV is worthwhile to control and potentially eradicate malaria worldwide.
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Affiliation(s)
- Jingjing Cai
- College of Basic Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Suilin Chen
- College of Basic Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China
| | - Feng Zhu
- College of Basic Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China
| | - Xiao Lu
- Department of Thoracic Surgery, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Taiping Liu
- College of Basic Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China
| | - Wenyue Xu
- College of Basic Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China
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20
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Nekorchuk DM, Gebrehiwot T, Lake M, Awoke W, Mihretie A, Wimberly MC. Comparing malaria early detection methods in a declining transmission setting in northwestern Ethiopia. BMC Public Health 2021; 21:788. [PMID: 33894764 PMCID: PMC8067323 DOI: 10.1186/s12889-021-10850-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 04/14/2021] [Indexed: 11/20/2022] Open
Abstract
Background Despite remarkable progress in the reduction of malaria incidence, this disease remains a public health threat to a significant portion of the world’s population. Surveillance, combined with early detection algorithms, can be an effective intervention strategy to inform timely public health responses to potential outbreaks. Our main objective was to compare the potential for detecting malaria outbreaks by selected event detection methods. Methods We used historical surveillance data with weekly counts of confirmed Plasmodium falciparum (including mixed) cases from the Amhara region of Ethiopia, where there was a resurgence of malaria in 2019 following several years of declining cases. We evaluated three methods for early detection of the 2019 malaria events: 1) the Centers for Disease Prevention and Control (CDC) Early Aberration Reporting System (EARS), 2) methods based on weekly statistical thresholds, including the WHO and Cullen methods, and 3) the Farrington methods. Results All of the methods evaluated performed better than a naïve random alarm generator. We also found distinct trade-offs between the percent of events detected and the percent of true positive alarms. CDC EARS and weekly statistical threshold methods had high event sensitivities (80–100% CDC; 57–100% weekly statistical) and low to moderate alarm specificities (25–40% CDC; 16–61% weekly statistical). Farrington variants had a wide range of scores (20–100% sensitivities; 16–100% specificities) and could achieve various balances between sensitivity and specificity. Conclusions Of the methods tested, we found that the Farrington improved method was most effective at maximizing both the percent of events detected and true positive alarms for our dataset (> 70% sensitivity and > 70% specificity). This method uses statistical models to establish thresholds while controlling for seasonality and multi-year trends, and we suggest that it and other model-based approaches should be considered more broadly for malaria early detection. Supplementary Information The online version contains supplementary material available at 10.1186/s12889-021-10850-5.
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Affiliation(s)
- Dawn M Nekorchuk
- Department of Geography and Environmental Sustainability, University of Oklahoma, Norman, OK, USA
| | | | | | - Worku Awoke
- School of Public Health, Bahir Dar University, Bahir Dar, Ethiopia
| | - Abere Mihretie
- Health, Development, and Anti-Malaria Association, Addis Ababa, Ethiopia
| | - Michael C Wimberly
- Department of Geography and Environmental Sustainability, University of Oklahoma, Norman, OK, USA.
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21
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McGregor D, Texeira da Silva E, Grignard L, Goncalves A, Vasileva H, Mabey D, Last A. The Epidemiology of Plasmodium falciparum Malaria in the Bijagos Islands of Guinea-Bissau. Am J Trop Med Hyg 2021; 104:2117-2122. [PMID: 33782209 PMCID: PMC8176492 DOI: 10.4269/ajtmh.20-1029] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/15/2020] [Indexed: 11/07/2022] Open
Abstract
Distribution of long-lasting insecticide-treated nets (LLINs), passive detection and treatment with artemisinin-based combination therapy (ACT), and intermittent preventive treatment in pregnancy (IPTp) are the mainstay malaria control measures of Guinea-Bissau’s national control programme. This study aimed to estimate the prevalence of Plasmodium falciparum on Bubaque, the most populous island of the country’s remote Bijagos archipelago. A cross-sectional survey was performed at the start of the rainy season in August 2017. Participants were recruited using systematic random sampling in a two-stage stratified cluster design. Malaria parasitemia was detected using rapid diagnostic tests (RDTs) and quantitative PCR (qPCR). Data on housing, education, larval source management, socioeconomic status, anemia, and malaria preventive measures were collected. Multivariable logistic regression models were constructed to identify associations with P. falciparum infection. Four hundred four persons (aged 6 months–79 years, median 17 years) were enrolled in the study. The prevalence of P. falciparum parasitemia was 5.8% by RDT (95% CI: 3.55–9.33) and 16.9% by qPCR (95% CI: 13.09–21.71). The prevalence of anemia was 74.3% (95% CI: 69.04–78.85) as defined by the WHO criteria. All sampled houses were found to have open eaves; 99.5% of the surveyed population reported sleeping under a bednet (95% CI: 97.8–99.9). Although reported LLIN use is high, there remains an appreciable prevalence of malaria, suggesting that transmission is ongoing and further tools are required to reduce the burden of the disease.
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Affiliation(s)
- David McGregor
- 1Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Eunice Texeira da Silva
- 1Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom.,2Region Sanitaria Bolama-Bijagós, Bubaque, Guinea-Bissau
| | - Lynn Grignard
- 3Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Adriana Goncalves
- 1Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Hristina Vasileva
- 1Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - David Mabey
- 1Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Anna Last
- 1Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
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22
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Wimberly MC, de Beurs KM, Loboda TV, Pan WK. Satellite Observations and Malaria: New Opportunities for Research and Applications. Trends Parasitol 2021; 37:525-537. [PMID: 33775559 PMCID: PMC8122067 DOI: 10.1016/j.pt.2021.03.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/04/2021] [Accepted: 03/05/2021] [Indexed: 12/15/2022]
Abstract
Satellite remote sensing provides a wealth of information about environmental factors that influence malaria transmission cycles and human populations at risk. Long-term observations facilitate analysis of climate–malaria relationships, and high-resolution data can be used to assess the effects of agriculture, urbanization, deforestation, and water management on malaria. New sources of very-high-resolution satellite imagery and synthetic aperture radar data will increase the precision and frequency of observations. Cloud computing platforms for remote sensing data combined with analysis-ready datasets and high-level data products have made satellite remote sensing more accessible to nonspecialists. Further collaboration between the malaria and remote sensing communities is needed to develop and implement useful geospatial data products that will support global efforts toward malaria control, elimination, and eradication.
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Affiliation(s)
- Michael C Wimberly
- Department of Geography and Environmental Sustainability, University of Oklahoma, Norman, OK, USA.
| | - Kirsten M de Beurs
- Department of Geography and Environmental Sustainability, University of Oklahoma, Norman, OK, USA
| | - Tatiana V Loboda
- Department of Geographical Sciences, University of Maryland, College Park, MD, USA
| | - William K Pan
- Duke Global Health Institute, Duke University, Durham, NC, USA
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23
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Yeshanew S, Dagne A, Taye B. Efficacy Study of Chloroquine to Plasmodium vivax Malaria in Darimu and Bure Districts, Southwest Ethiopia. Infect Drug Resist 2021; 14:795-803. [PMID: 33688214 PMCID: PMC7936702 DOI: 10.2147/idr.s300692] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 02/22/2021] [Indexed: 11/27/2022] Open
Abstract
Background Chloroquine (CQ) is the first line treatment for vivax malaria in Ethiopia. However, the therapeutic efficacy of the drug is now declining. Several reports from different areas of the country showed CQ-vivax treatment failure increasing. This study therefore aimed to provide additional data on the therapeutic efficacy of CQ against Plasmodium vivax malaria from two districts of Southwestern Ethiopia. Methods An observational prospective study among P. vivax malaria infected individuals was conducted in two districts of Southwest Ethiopia for a period of 28 follow-up days. Study participants were treated with 25 mg/kg of standard CQ for 3 consecutive days according to the procedure. Microscopic blood film examinations and other clinical assessments were measured within the follow-up period on a weekly basis. Results A total of 115 patients were enrolled in the study. Sixty-five were from Darimu and 50 were from Bure districts. The majority (67%) of study participants were male and 86.1% (99/115) were below 35 years old. The study revealed that CQ treatment was able to clear vivax malaria parasites and febrile within a week. During the follow-up study period, recurrence of vivax parasitemia was not recorded. However, there was a marked heterogeneity with respect to fever clearance time, parasitemia load, and carriage of parasite gametocyte within 72 hours of post-treatment between the two study areas. Conclusion The present study revealed that CQ has good clinical and parasitological response to vivax malaria in the study areas. Thus, it can be continued as the first line P. vivax malaria treatment. However, further monitoring and evaluation of the drug should be considered.
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Affiliation(s)
- Solomon Yeshanew
- Department of Biology, Debre Markos University, Debre Markos, Ethiopia
| | | | - Behailu Taye
- Department of Biology, Mettu University, Mettu, Ethiopia
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24
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Jones J, Murray GPD, McCall PJ. A minimal 3D model of mosquito flight behaviour around the human baited bed net. Malar J 2021; 20:24. [PMID: 33413370 PMCID: PMC7792054 DOI: 10.1186/s12936-020-03546-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 12/12/2020] [Indexed: 02/08/2023] Open
Abstract
Background Advances in digitized video-tracking and behavioural analysis have enabled accurate recording and quantification of mosquito flight and host-seeking behaviours, facilitating development of individual (agent) based models at much finer spatial scales than previously possible. Methods Quantified behavioural parameters were used to create a novel virtual testing model, capable of accurately simulating indoor flight behaviour by a virtual population of host-seeking mosquitoes as they interact with and respond to simulated stimuli from a human-occupied bed net. The model is described, including base mosquito behaviour, state transitions, environmental representation and host stimulus representation. Results In the absence of a bed net and human host bait, flight distribution of the model population was relatively uniform throughout the arena. Introducing an unbaited untreated bed net induced a change in distribution with an increase in landing events on the net surface, predominantly on the sides of the net. Adding the presence of a simulated human bait dramatically impacted flight distribution patterns, exploratory foraging and, the number and distribution of landing positions on the net, which were determined largely by the orientation of the human within. The model replicates experimental results with free-flying living mosquitoes at human-occupied bed nets, where contact occurs predominantly on the top surface of the net. This accuracy is important as it quantifies exposure to the lethal insecticide residues that may be unique to the net roof (or theoretically any other surface). Number of net contacts and height of contacts decreased with increasing attractant dispersal noise. Conclusions Results generated by the model are an accurate representation of actual mosquito behaviour recorded at and around a human-occupied bed net in untreated and insecticide-treated nets. This fine-grained model is highly flexible and has significant potential for in silico screening of novel bed net designs, potentially reducing time and cost and accelerating the deployment of new and more effective tools for protecting against malaria in sub-Saharan Africa.
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Affiliation(s)
- Jeff Jones
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA, Liverpool, UK
| | - Gregory P D Murray
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA, Liverpool, UK
| | - Philip J McCall
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA, Liverpool, UK.
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25
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Jiang T, Cheng W, Yao Y, Tan H, Wu K, Li J. Molecular surveillance of anti-malarial resistance Pfdhfr and Pfdhps polymorphisms in African and Southeast Asia Plasmodium falciparum imported parasites to Wuhan, China. Malar J 2020; 19:434. [PMID: 33238987 PMCID: PMC7691106 DOI: 10.1186/s12936-020-03509-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 11/19/2020] [Indexed: 01/02/2023] Open
Abstract
Background Anti-malarial drug resistance is a severe challenge for eventual control and global elimination of malaria. Resistance to sulfadoxine-pyrimethamine (SP) increases as mutations accumulate in the Pfdhfr and Pfdhps genes. This study aimed to assess the polymorphisms and prevalence of mutation in these genes in the Plasmodium falciparum infecting migrant workers returning to Wuhan, China. Methods Blood samples were collected for 9 years (2011–2019). Parasite genomic DNA was extracted from blood spots on filter paper. The mutations were evaluated by nested PCR and sequencing. The single-nucleotide polymorphisms (SNPs) and haplotypes of the Pfdhfr and Pfdhps genes were analysed. Results Pfdhfr codon 108 showed a 94.7% mutation rate, while for Pfdhps, the rate for codon 437 was 79.0%. In total, five unique haplotypes at the Pfdhfr locus and 11 haplotypes at the Pfdhps locus were found while the Pfdhfr-Pfdhps combined loci revealed 28 unique haplotypes. A triple mutant (IRNI) of Pfdhfr was the most prevalent haplotype (84.4%). For Pfdhps, a single mutant (SGKAA) and a double mutant (SGEAA) were detected at frequencies of 37.8 and 22.3%, respectively. Among the combined haplotypes, a quadruple mutant (IRNI-SGKAA) was the most common, with a 30.0% frequency, followed by a quintuplet mutant (IRNI-SGEAA) with a frequency of 20.4%. Conclusion The high prevalence and saturation of Pfdhfr haplotypes and the medium prevalence of Pfdhps haplotypes demonstrated in the present data will provide support for predicting the status and progression of antifolate resistance in malaria-endemic regions and imported malaria in nonendemic areas. Additional interventions to evaluate and prevent SP resistance should be continuously considered.
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Affiliation(s)
- Tingting Jiang
- Department of Human Parasitology, School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, 442000, China.,Department of Infectious Diseases, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, China
| | - Weijia Cheng
- Department of Human Parasitology, School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, 442000, China.,Department of Infectious Diseases, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, China
| | - Yi Yao
- Department of Human Parasitology, School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, 442000, China.,Department of Infectious Diseases, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, China
| | - Huabing Tan
- Department of Human Parasitology, School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, 442000, China.,Department of Infectious Diseases, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, China
| | - Kai Wu
- Department of Schistosomiasis and Endemic Diseases, Wuhan City Center for Disease Prevention and Control, Wuhan, 430015, China.
| | - Jian Li
- Department of Human Parasitology, School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, 442000, China. .,Department of Infectious Diseases, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, China.
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26
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Nakakana UN, Onankpa BO, Mohammed IA, Jega RM, Jiya NM. Where have all the parasites gone? Unusual Plasmodium falciparum monoparasitaemia in a cross-sectional malariometric survey in northern Nigeria. F1000Res 2020; 9:301. [PMID: 33214872 PMCID: PMC7658729 DOI: 10.12688/f1000research.20997.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/15/2020] [Indexed: 11/20/2022] Open
Abstract
Background: Malaria is caused by one of five currently known
Plasmodium parasite species causing disease in humans. While modelling has provided information of the vector, the same is not entirely the case for the parasite. The World Malaria reports of 2014 to 2016 reported 100% of confirmed cases from Nigeria being due to
Plasmodium falciparum. Generally, about 98% of cases of uncomplicated malaria in most regions surveyed in Nigeria recently is due to
P. falciparum, with the remainder being due to
P. malariae. This study aimed to determine the proportions of
Plasmodium parasites causing uncomplicated malaria in Wamakko Local Government Area of Sokoto State, north-western Nigeria. Methods: The study was a descriptive, cross-sectional study conducted during the rainy season and dry season in north-western Nigeria. The area has a ‘local steppe’ climate and Sudanian Savannah vegetation. Sampling was via multistage cluster sampling. Selected participants were examined for pallor, palpable splenomegaly and signs of complicated malaria. Blood samples were also taken for rapid diagnosis of malaria and thick and thin films to identify parasitaemia and the parasite species. Participants found to have malaria were treated with Artemether/Lumefantrine and those with complicated malaria were referred to the nearest hospital. Results: We found a parasite prevalence of 34.8% overall, which was higher in the rainy season (49.3%) than in the dry season (20.2%). There was monoparasitaemia of
Plasmodium falciparum throughout the study area, irrespective of the clinical status of the participant. Mapping of the parasite was extended throughout the Local Government Area and the State. Conclusions: Despite the intermediate endemicity in the area.
P. falciparum monoparasitaemia affirms theories of disappearance of other parasite species, either due to faltering control of
P. falciparum or more efficient control of other species.
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Affiliation(s)
- Usman Nasir Nakakana
- Department of Paediatrics, Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria.,Medical Research Council Unit The Gambia at London School of Tropical Medicine and Hygiene, Fajara, The Gambia
| | - Ben O Onankpa
- Department of Paediatrics, Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria
| | - Ismaila Ahmed Mohammed
- Department of Community Medicine, Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria
| | - Ridwan M Jega
- Department of Paediatrics, Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria
| | - Nma Muhammad Jiya
- Department of Paediatrics, Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria
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27
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Shibeshi MA, Kifle ZD, Atnafie SA. Antimalarial Drug Resistance and Novel Targets for Antimalarial Drug Discovery. Infect Drug Resist 2020; 13:4047-4060. [PMID: 33204122 PMCID: PMC7666977 DOI: 10.2147/idr.s279433] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 10/29/2020] [Indexed: 12/16/2022] Open
Abstract
Malaria is among the most devastating and widespread tropical parasitic diseases in which most prevalent in developing countries. Antimalarial drug resistance is the ability of a parasite strain to survive and/or to multiply despite the administration and absorption of medicine given in doses equal to or higher than those usually recommended. Among the factors which facilitate the emergence of resistance to existing antimalarial drugs: the parasite mutation rate, the overall parasite load, the strength of drug selected, the treatment compliance, poor adherence to malaria treatment guideline, improper dosing, poor pharmacokinetic properties, fake drugs lead to inadequate drug exposure on parasites, and poor-quality antimalarial may aid and abet resistance. Malaria vaccines can be categorized into three categories: pre-erythrocytic, blood-stage, and transmission-blocking vaccines. Molecular markers of antimalarial drug resistance are used to screen for the emergence of resistance and assess its spread. It provides information about the parasite genetics associated with resistance, either single nucleotide polymorphisms or gene copy number variations which are associated with decreased susceptibility of parasites to antimalarial drugs. Glucose transporter PfHT1, kinases (Plasmodium kinome), food vacuole, apicoplast, cysteine proteases, and aminopeptidases are the novel targets for the development of new antimalarial drugs. Therefore, this review summarizes the antimalarial drug resistance and novel targets of antimalarial drugs.
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Affiliation(s)
- Melkamu Adigo Shibeshi
- Department of Pharmacology, School of Pharmacy, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
| | - Zemene Demelash Kifle
- Department of Pharmacology, School of Pharmacy, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
| | - Seyfe Asrade Atnafie
- Department of Pharmacology, School of Pharmacy, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
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28
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Estimating the optimal interval between rounds of indoor residual spraying of insecticide using malaria incidence data from cohort studies. PLoS One 2020; 15:e0241033. [PMID: 33095812 PMCID: PMC7584202 DOI: 10.1371/journal.pone.0241033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 10/07/2020] [Indexed: 12/05/2022] Open
Abstract
Background Indoor residual spraying (IRS) reduces vector densities and malaria transmission, however, the most effective spraying intervals for IRS have not been well established. We estimated the optimal timing interval for IRS using a statistical approach. Methods Six rounds of IRS were implemented in Tororo District, a historically high malaria transmission setting in Uganda, during the study period (3 rounds with bendiocarb active ingredient (Ficam®): December 2014 to December 2015, and 3 rounds with pirimiphos methyl active ingredient (Actellic 300®CS): June 2016 to July 2018). A generalized additive model was used to estimate the optimal timing interval for IRS based on the predicted malaria incidence. The model was fitted to clinical incidence data from a cohort of children aged 0.5–10 years from selected households observed throughout the study period. Results 494 children, 67% aged less than 5 years at enrolment were analysed. Six-months period incidence of malaria decreased from 2.96 per person-years at the baseline to 1.74 following the first round of IRS and then to 0.02 after 6 rounds of IRS. The optimal time interval for IRS differed between bendiocarb and pirimiphos methyl and by IRS round. To retain an optimum impact, bendiocarb would require respraying 17 (95% CI: 14.2–21.0) weeks after application whereas pirimiphos methyl could remain impactful for 40 (95% CI: 37.0–42.8) weeks, although in the final year this estimates 36 (95% CI: 32.7–37.7) weeks. However, we could not estimate from the data the optimal time after the second and third rounds of bendiocarb and after the second round of pirimiphos methyl. Neither the amount of rainfall nor the EIR nor the distribution of nets were found to be statistically significant for determining the time period between spray rounds. Conclusion In our setting, the effect of the two IRS products was distinct. Statistically, pirimiphos methyl provided a longer window of protection than bendiocarb, although impact varied between different spray rounds and years which was not explained by rainfall or EIR or distribution of nets in our statistical approach. Understanding the effectiveness of IRS and how long it lasts can help for planning campaigns, but one should consider the financial cost and insecticide resistance. Monitoring the timing of spray campaigns using clinical incidence could be repeated in future programs to help determine the average period of protectivity of these products.
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29
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Naville R, Subtil F, Sy M, Marquis M, Costes P, Letrilliart L. Scope of health problems managed by general practitioners in Mali and France: awaiting practice transition in sub-Saharan Africa? Fam Pract 2020; 37:668-674. [PMID: 32531028 DOI: 10.1093/fampra/cmaa035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Minimal data are available on the clinical activity of general practitioners (GPs) in Africa. OBJECTIVE To describe the health problems managed by GPs in Mali as compared with France where epidemiological transition is already advanced. METHODS A retrospective, multicenter study, conducted in five Malian Community Health Centers. We compared their consultation data to those of the ECOGEN (Eléments de la COnsultation en médecine GENérale) study conducted in 128 French general practices, after data standardization for age and sex. RESULTS Malian and French databases included 19 068 and 19 341 consultations, respectively. Patients had an average of 1.2 health problems managed per consultation in Mali, versus 2.2 in France. They were dominated by infections (51.3%) in Mali, including malaria (24.9%), pneumonia (9.0%) and gastrointestinal infections (5.0%). In comparison with French GPs, Malian GPs more frequently managed cardiovascular (20.2% versus 13.5%), respiratory (15.0% versus 12.4%) and digestive (13.3% versus 7.8%) problems, and less frequently musculoskeletal (3.1% versus 12.6%), endocrine/metabolic (1.5% versus 10.7%) and psychological (0.2% versus 8.2%) problems. The main activity performed by French GPs was prevention (11.0%), which was nominal in Mali. Apart from hypertension, which accounted for 18.9% of the health problems managed in Mali, chronic conditions were less often managed by Malian GPs than by French GPs (12.3% versus 39.6%). CONCLUSIONS Africa is currently at the crossroads where chronic conditions carried with the epidemiological transition are progressing, while the burden of communicable diseases is still overwhelming. Along with the enhancing medicalization of primary care in Mali, the transition of practices is just emerging.
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Affiliation(s)
- Raphaël Naville
- Collège universitaire de médecine générale, Université Claude Bernard Lyon 1, Univ. Lyon, Lyon, France
| | - Fabien Subtil
- Service de Biostatistique-Bioinformatique, Hospices Civils de Lyon, Lyon, France
| | | | - Michel Marquis
- Agence régionale de santé Auvergne-Rhône-Alpes, Direction de la Santé Publique, Lyon, France
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30
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Atherstone C, Mgode GF, Dhand NK, Alonso S, Grace D, Ward MP, Mor SM. Selected Endemic Zoonoses in Pigs Presenting for Slaughter in Kampala, Uganda. Am J Trop Med Hyg 2020; 103:2552-2560. [PMID: 33069266 PMCID: PMC7695076 DOI: 10.4269/ajtmh.20-0033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Leptospirosis, brucellosis, and Q fever (coxiellosis) are bacterial zoonoses that cause acute febrile illness in people as well as reproductive losses in pigs. Pig keeping is an increasingly important livelihood to millions of smallholder farmers in Uganda because of exponential increases in demand for pork. The prevalence of leptospirosis and Q fever in pigs is unknown, and the few studies of porcine brucellosis have estimated a range of seroprevalence. Therefore, we undertook a prevalence survey of leptospirosis, brucellosis, and Q fever in pigs using quantitative real-time PCR to determine the potential importance of these zoonoses to the growing pig sector in Uganda. Six hundred forty-nine pigs were sampled in 2015–2016 at an urban pork slaughterhouse. Ten percent of pigs (n = 68) had leptospiral DNA in either their kidney or reproductive tissue. In adjusted analyses, variables predictive of leptospiral status included female sex (odds ratio [OR]: 2.37, P < 0.01) and pigs sampled in March 2016 (OR: 2.23, P = 0.02) and October 2016 (OR: 0.30, P = 0.04). DNA fingerprinting revealed circulation of at least four distinct serovars in these pigs. Brucella spp. and Coxiella burnetii DNA were not detected in any sampled pig. This is the first report of widespread circulation of pathogenic Leptospira spp. in pigs in Uganda, suggesting that leptospirosis likely has a greater impact on the health of pigs than was previously recognized. Pig farmers, pig traders, and slaughterhouse workers may be at greatest occupational risk because of their direct contact with infective leptospires in aborted fetuses, bodily fluids, and other tissues.
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Affiliation(s)
- Christine Atherstone
- Sydney School of Veterinary Science, The University of Sydney, Camperdown, Australia
| | - Georgies F Mgode
- Pest Management Centre, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Navneet K Dhand
- Sydney School of Veterinary Science, The University of Sydney, Camperdown, Australia
| | - Silvia Alonso
- International Livestock Research Institute, Addis Ababa, Ethiopia
| | - Delia Grace
- Natural Resources Institute, University of Greenwich, Kent, United Kingdom.,International Livestock Research Institute, Nairobi, Kenya
| | - Michael P Ward
- Sydney School of Veterinary Science, The University of Sydney, Camperdown, Australia
| | - Siobhan M Mor
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom.,Sydney School of Veterinary Science, The University of Sydney, Camperdown, Australia
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31
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Su MP, Georgiades M, Bagi J, Kyrou K, Crisanti A, Albert JT. Assessing the acoustic behaviour of Anopheles gambiae (s.l.) dsxF mutants: implications for vector control. Parasit Vectors 2020; 13:507. [PMID: 33028410 PMCID: PMC7539510 DOI: 10.1186/s13071-020-04382-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 09/28/2020] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Release of gene-drive mutants to suppress Anopheles mosquito reproduction is a promising method of malaria control. However, many scientific, regulatory and ethical questions remain before transgenic mosquitoes can be utilised in the field. At a behavioural level, gene-drive carrying mutants should be at least as sexually attractive as the wildtype populations they compete against, with a key element of Anopheles copulation being acoustic courtship. We analysed sound emissions and acoustic preference in a doublesex mutant previously used to collapse Anopheles gambiae (s.l.) cages. METHODS Anopheles rely on flight tones produced by the beating of their wings for acoustic mating communication. We assessed the impact of disrupting a female-specific isoform of the doublesex gene (dsxF) on the wing beat frequency (WBF; measured as flight tone) of males (XY) and females (XX) in homozygous dsxF- mutants (dsxF-/-), heterozygous dsxF- carriers (dsxF+/-) and G3 dsxF+ controls (dsxF+/+). To exclude non-genetic influences, we controlled for temperature and wing length. We used a phonotaxis assay to test the acoustic preferences of mutant and control mosquitoes. RESULTS A previous study showed an altered phenotype only for dsxF-/- females, who appear intersex, suggesting that the female-specific dsxF allele is haplosufficient. We identified significant, dose-dependent increases in the WBF of both dsxF-/- and dsxF+/- females compared to dsxF+/+ females. All female WBFs remained significantly lower than male equivalents, though. Males showed stronger phonotactic responses to the WBFs of control dsxF+/+ females than to those of dsxF+/- and dsxF-/- females. We found no evidence of phonotaxis in any female genotype. No male genotypes displayed any deviations from controls. CONCLUSIONS A prerequisite for anopheline copulation is the phonotactic attraction of males towards female flight tones within mating swarms. Reductions in mutant acoustic attractiveness diminish their mating efficiency and thus the efficacy of population control efforts. Caged population assessments may not successfully reproduce natural mating scenarios. We propose to amend existing testing protocols to better reflect competition between mutants and target populations. Our findings confirm that dsxF disruption has no effect on males; for some phenotypic traits, such as female WBFs, the effects of dsxF appear dose-dependent rather than haplosufficient.
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Affiliation(s)
- Matthew P Su
- Ear Institute, University College London, 332 Grays Inn Road, London, WC1X 8EE, UK.,The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.,Division of Biological Science, Nagoya University, Nagoya, 464-8602, Japan
| | - Marcos Georgiades
- Ear Institute, University College London, 332 Grays Inn Road, London, WC1X 8EE, UK.,The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Judit Bagi
- Ear Institute, University College London, 332 Grays Inn Road, London, WC1X 8EE, UK.,The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Kyros Kyrou
- Department of Life Sciences, Imperial College London, London, UK
| | - Andrea Crisanti
- Department of Life Sciences, Imperial College London, London, UK
| | - Joerg T Albert
- Ear Institute, University College London, 332 Grays Inn Road, London, WC1X 8EE, UK. .,The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
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32
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Moyo SJ, Manyahi J, Blomberg B, Tellevik MG, Masoud NS, Aboud S, Manji K, Roberts AP, Hanevik K, Mørch K, Langeland N. Bacteraemia, Malaria, and Case Fatality Among Children Hospitalized With Fever in Dar es Salaam, Tanzania. Front Microbiol 2020; 11:2118. [PMID: 33013772 PMCID: PMC7511546 DOI: 10.3389/fmicb.2020.02118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/11/2020] [Indexed: 12/31/2022] Open
Abstract
Background Febrile illness is the commonest cause of hospitalization in children <5 years in sub-Saharan Africa, and bacterial bloodstream infections and malaria are major causes of death. Methods From March 2017 to July 2018, we enrolled 2,226 children aged 0–5 years hospitalized due to fever in four major public hospitals of Dar es Salaam, namely, Amana, Temeke, and Mwananyamala Regional Hospitals and Muhimbili National Hospital. We recorded social demographic and clinical data, and we performed blood-culture and HIV-antibody testing. We used qPCR to quantify Plasmodium falciparum parasitaemia and Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) to identify bacterial isolates. Disk diffusion method was used for antimicrobial susceptibility testing. Results Nineteen percent of the children (426/2,226) had pathogens detected from blood. Eleven percent (236/2,226) of the children had bacteraemia/fungaemia and 10% (204/2,063) had P. falciparum malaria. Ten children had concomitant malaria and bacteraemia. Gram-negative bacteria (64%) were more frequent than Gram-positive (32%) and fungi (4%). Over 50% of Gram-negative bacteria were extended-spectrum beta-lactamase (ESBL) producers and multidrug resistant. Methicillin resistant Staphylococcus aureus (MRSA) was found in 11/42 (26.2%). The most severe form of clinical malaria was associated with high parasitaemia (>four million genomes/μL) of P. falciparum in plasma. Overall, in-hospital death was 4% (89/2,146), and it was higher in children with bacteraemia (8%, 18/227) than malaria (2%, 4/194, p = 0.007). Risk factors for death were bacteraemia (p = 0.03), unconsciousness at admission (p < 0.001), and admission at a tertiary hospital (p = 0.003). Conclusion Compared to previous studies in this region, our study showed a reduction in malaria prevalence, a decrease in in-hospital mortality, and an increase in antimicrobial resistance (AMR) including ESBLs and multidrug resistance. An increase of AMR highlights the importance of continued strengthening of diagnostic capability and antimicrobial stewardship programs. We also found malaria and bacteraemia contributed equally in causing febrile illness, but bacteraemia caused higher in-hospital death. The most severe form of clinical malaria was associated with P. falciparum parasitaemia.
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Affiliation(s)
- Sabrina J Moyo
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Joel Manyahi
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Bjørn Blomberg
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Norwegian National Advisory Unit on Tropical Infectious Diseases, Haukeland University Hospital, Bergen, Norway
| | - Marit Gjerde Tellevik
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Haukeland University Hospital, Bergen, Norway.,Department of Microbiology, Haukeland University Hospital, Bergen, Norway
| | - Nahya Salim Masoud
- Department of Paediatrics, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Said Aboud
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Karim Manji
- Department of Paediatrics, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Adam P Roberts
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Kurt Hanevik
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Norwegian National Advisory Unit on Tropical Infectious Diseases, Haukeland University Hospital, Bergen, Norway
| | - Kristine Mørch
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Norwegian National Advisory Unit on Tropical Infectious Diseases, Haukeland University Hospital, Bergen, Norway
| | - Nina Langeland
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Norwegian National Advisory Unit on Tropical Infectious Diseases, Haukeland University Hospital, Bergen, Norway
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Ryan SJ, Martin AC, Walia B, Winters A, Larsen DA. Comparing prioritization strategies for delivering indoor residual spray (IRS) implementation, using a network approach. Malar J 2020; 19:326. [PMID: 32887619 PMCID: PMC7650283 DOI: 10.1186/s12936-020-03398-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/30/2020] [Indexed: 11/28/2022] Open
Abstract
Background Indoor residual spraying (IRS) is an effective method to control malaria-transmitting Anopheles mosquitoes and often complements insecticide-treated mosquito nets, the predominant malaria vector control intervention. With insufficient funds to cover every household, malaria control programs must balance the malaria risk to a particular human community against the financial cost of spraying that community. This study creates a framework for modelling the distance to households for targeting IRS implementation, and applies it to potential risk prioritization strategies in four provinces (Luapula, Muchinga, Eastern, and Northern) in Zambia. Methods Optimal network models were used to assess the travel distance of routes between operations bases and human communities identified through remote sensing. Network travel distances were compared to Euclidean distances, to demonstrate the importance of accounting for road routes. The distance to reaching communities for different risk prioritization strategies were then compared assuming sufficient funds to spray 50% of households, using four underlying malarial risk maps: (a) predicted Plasmodium falciparum parasite rate in 2–10 years olds (PfPR), or (b) predicted probability of the presence of each of three main malaria transmitting anopheline vectors (Anopheles arabiensis, Anopheles funestus, Anopheles gambiae). Results The estimated one-way network route distance to reach communities to deliver IRS ranged from 0.05 to 115.69 km. Euclidean distance over and under-estimated these routes by − 101.21 to 41.79 km per trip, as compared to the network route method. There was little overlap between risk map prioritization strategies, both at a district-by-district scale, and across all four provinces. At both scales, agreement for inclusion or exclusion from IRS across all four prioritization strategies occurred in less than 10% of houses. The distances to reaching prioritized communities were either lower, or not statistically different from non-prioritized communities, at both scales of strategy. Conclusion Variation in distance to targeted communities differed depending on risk prioritization strategy used, and higher risk prioritization did not necessarily translate into greater distances in reaching a human community. These findings from Zambia suggest that areas with higher malaria burden may not necessarily be more remote than areas with lower malaria burden.
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Affiliation(s)
- Sadie J Ryan
- Quantitative Disease Ecology and Conservation (QDEC) Lab, Department of Geography, University of Florida, Gainesville, FL, 32611, USA. .,Emerging Pathogens Institute, University of Florida, Gainesville, FL, 32610, USA.
| | | | - Bhavneet Walia
- Department of Public Health, Syracuse University, Syracuse, NY, 13210, USA
| | - Anna Winters
- Akros, Lusaka, Zambia.,University of Montana School of Public and Community Health Science, Missoula, MT, USA
| | - David A Larsen
- Department of Public Health, Syracuse University, Syracuse, NY, 13210, USA
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Matheson AI, Mogeni OD, Lacsina JR, Ochieng M, Audi A, Bigogo G, Neatherlin J, Margolis HS, Fields B, Ahenda P, Walson JL, Montgomery JM. No Evidence of Acute Dengue Virus Infections at a Rural Site in Western Kenya, 2011 and 2013. Am J Trop Med Hyg 2020; 103:2054-2058. [PMID: 32876014 DOI: 10.4269/ajtmh.20-0132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The incidence and spread of dengue virus (DENV) have increased rapidly in recent decades. Dengue is underreported in Africa, but recent outbreaks and seroprevalence data suggest that DENV is widespread there. A lack of ongoing surveillance limits knowledge about its spatial reach and hinders disease control planning. We sought to add data on dengue distribution in Kenya through diagnostic testing of serum specimens from persons with an acute febrile illness (AFI) attending an outpatient clinic in rural western Kenya (Asembo) during rainy seasons. Patients with symptoms not likely to be misclassified as dengue (e.g., diarrhea and anemia), those with a positive diagnostic laboratory results which explained their febrile illness, or those with serum collected more than 5 days after fever onset were excluded. However, febrile patients with a positive malaria smear were included in the study. We used reverse transcription polymerase chain reaction (RT-PCR) to test for DENV and IgM anti-DENV to test for recent infection. Of the 615 serum specimens available for testing, none were dengue positive by either RT-PCR or IgM anti-DENV testing. Dengue did not appear to be a cause of febrile illness in this area of western Kenya, although our relatively small sample size may not have identified DENV infections occurring at low incidence. A more widespread AFI surveillance system that includes dengue diagnostic testing by RT-PCR and antibody-based methods is required to more definitively gauge the size and geographic distribution of DENV infection in western Kenya.
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Affiliation(s)
- Alastair I Matheson
- Department of Global Health, University of Washington, Seattle, Washington.,Department of Epidemiology, University of Washington, Seattle, Washington
| | - Ondari D Mogeni
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Joshua R Lacsina
- Department of Medicine, University of Washington, Seattle, Washington
| | - Melvin Ochieng
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Allan Audi
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Godfrey Bigogo
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya
| | - John Neatherlin
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Harold S Margolis
- Dengue Branch, Division of Vectorborne Diseases, Centers for Disease Control and Prevention, San Juan, Puerto Rico
| | - Barry Fields
- Division of Global Health Protection, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Petronella Ahenda
- School of Public Health, Texas A&M University, College Station, Texas
| | - Judd L Walson
- Department of Medicine, University of Washington, Seattle, Washington.,Department of Global Health, University of Washington, Seattle, Washington.,Department of Epidemiology, University of Washington, Seattle, Washington
| | - Joel M Montgomery
- Division of Global Health Protection, Centers for Disease Control and Prevention, Atlanta, Georgia
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Maseko A, Nunu WN. Risk factors associated with high malaria incidence among communities in selected wards in Binga district, Zimbabwe: a case-control study. SCIENTIFIC AFRICAN 2020. [DOI: 10.1016/j.sciaf.2020.e00473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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Kemibala EE, Mafra-Neto A, Saroli J, Silva R, Philbert A, Ng'habi K, Foster WA, Dekker T, Mboera LEG. Is Anopheles gambiae attraction to floral and human skin-based odours and their combination modulated by previous blood meal experience? Malar J 2020; 19:318. [PMID: 32873302 PMCID: PMC7466419 DOI: 10.1186/s12936-020-03395-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/26/2020] [Indexed: 11/21/2022] Open
Abstract
Background Mosquitoes use odours to find energy resources, blood hosts and oviposition sites. While these odour sources are normally spatio-temporally segregated in a mosquito’s life history, here this study explored to what extent a combination of flower- and human-mimicking synthetic volatiles would attract the malaria vector Anopheles gambiae sensu stricto (s.s.) Methods In the laboratory and in large (80 m2) outdoor cages in Tanzania, nulliparous and parous A. gambiae s.s. were offered choices between a blend of human skin volatiles (Skin Lure), a blend of floral volatiles (Vectrax), or a combination thereof. The blends consisted of odours that induce distinct, non-overlapping activation patterns in the olfactory circuitry, in sensory neurons expressing olfactory receptors (ORs) and ionotropic receptors (IRs), respectively. Catches were compared between treatments. Results In the laboratory nulliparous and parous mosquitoes preferred skin odours and combinations thereof over floral odours. However, in semi-field settings nulliparous were significantly more caught with floral odours, whereas no differences were observed for parous females. Combining floral and human volatiles did not augment attractiveness. Conclusions Nulliparous and parous A. gambiae s.s. are attracted to combinations of odours derived from spatio-temporally segregated resources in mosquito life-history (floral and human volatiles). This is favourable as mosquito populations are comprised of individuals whose nutritional and developmental state steer them to diverging odours sources, baits that attract irrespective of mosquito status could enhance overall effectiveness and use in monitoring and control. However, combinations of floral and skin odours did not augment attraction in semi-field settings, in spite of the fact that these blends activate distinct sets of sensory neurons. Instead, mosquito preference appeared to be modulated by blood meal experience from floral to a more generic attraction to odour blends. Results are discussed both from an odour coding, as well as from an application perspective.
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Affiliation(s)
- Elison E Kemibala
- Ministry of Health, Community Development, Gender, Elderly and Children, Vector Control Training Centre, P.O. Box 136, Muheza, Tanzania. .,University of Dar es Salaam, Dar es Salaam, Tanzania.
| | | | - Jesse Saroli
- ISCA Technologies, 1230, West Spring St, Riverside, CA, 92507, USA
| | - Rodrigo Silva
- ISCA Technologies, 1230, West Spring St, Riverside, CA, 92507, USA
| | | | - Kija Ng'habi
- University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Woodbridge A Foster
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH, USA.,Department of Entomology, The Ohio State University, Columbus, OH, USA
| | - Teun Dekker
- Swedish University of Agricultural Sciences, Alnarp, Uppsala, Sweden.,BioInnovate AB, Lund, Sweden
| | - Leonard E G Mboera
- SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro, Tanzania
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Kamya MR, Kakuru A, Muhindo M, Arinaitwe E, Nankabirwa JI, Rek J, Bigira V, Kapisi J, Wanzira H, Achan J, Natureeba P, Gasasira A, Havlir D, Jagannathan P, Rosenthal PJ, Rodriguez-Barraquer I, Dorsey G. The Impact of Control Interventions on Malaria Burden in Young Children in a Historically High-Transmission District of Uganda: A Pooled Analysis of Cohort Studies from 2007 to 2018. Am J Trop Med Hyg 2020; 103:785-792. [PMID: 32431280 PMCID: PMC7410449 DOI: 10.4269/ajtmh.20-0100] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
There is limited evidence on whether malaria elimination is feasible in high-transmission areas of Africa. Between 2007 and 2018, we measured the impact of malaria control interventions in young children enrolled in three clinical trials and two observational studies in Tororo, Uganda, a historically high-transmission area. Data were pooled from children aged 0.5–2 years. Interventions included individually assigned chemoprevention and repeated rounds of indoor residual spraying (IRS) of insecticide. All children received long-lasting insecticidal nets (LLINs) and treatment for symptomatic malaria with artemisinin-based combination therapy. Malaria incidence was measured using passive surveillance and parasite prevalence by microscopy and molecular methods at regular intervals. Poisson’s generalized linear mixed-effects models were used to estimate the impact of various control interventions. In total, 939 children were followed over 1,221.7 person years. In the absence of chemoprevention and IRS (reference group), malaria incidence was 4.94 episodes per person year and parasite prevalence 47.3%. Compared with the reference group, implementation of IRS was associated with a 97.6% decrease (95% CI: 93.3–99.1%, P = 0.001) in the incidence of malaria and a 96.0% decrease (95% CI: 91.3–98.2%, P < 0.001) in parasite prevalence (both measured after the fifth and sixth rounds of IRS). The addition of chemoprevention with monthly dihydroartemisinin–piperaquine to IRS was associated with a 99.5% decrease (95% CI: 98.6–99.9%, P < 0.001) in the incidence of malaria. In a historically high–malaria burden area of Uganda, a combination of LLINs, effective case management, IRS, and chemoprevention was associated with almost complete elimination of malaria in young children.
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Affiliation(s)
- Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda.,Department of Medicine, Makerere University, Kampala, Uganda
| | - Abel Kakuru
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Mary Muhindo
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda.,Department of Medicine, Makerere University, Kampala, Uganda
| | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Victor Bigira
- Uganda National Health Laboratory Services, Kampala, Uganda
| | - James Kapisi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Jane Achan
- Medical Research Council Unit, Banjul, The Gambia
| | - Paul Natureeba
- Makerere University-John Hopkins University Collaboration, Kampala, Uganda
| | - Anne Gasasira
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Diane Havlir
- Department of Medicine, University of California San Francisco, San Francisco, California
| | | | - Philip J Rosenthal
- Department of Medicine, University of California San Francisco, San Francisco, California
| | | | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, California
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Kamau A, Mogeni P, Okiro EA, Snow RW, Bejon P. A systematic review of changing malaria disease burden in sub-Saharan Africa since 2000: comparing model predictions and empirical observations. BMC Med 2020; 18:94. [PMID: 32345315 PMCID: PMC7189714 DOI: 10.1186/s12916-020-01559-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/16/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The most widely used measures of declining burden of malaria across sub-Saharan Africa are predictions from geospatial models. These models apply spatiotemporal autocorrelations and covariates to parasite prevalence data and then use a function of parasite prevalence to predict clinical malaria incidence. We attempted to assess whether trends in malaria cases, based on local surveillance, were similar to those captured by Malaria Atlas Project (MAP) incidence surfaces. METHODS We undertook a systematic review (PROSPERO International Prospective Register of Systematic Reviews; ID = CRD42019116834) to identify empirical data on clinical malaria in Africa since 2000, where reports covered at least 5 continuous years. The trends in empirical data were then compared with the trends of time-space matched clinical malaria incidence from MAP using the Spearman rank correlation. The correlations (rho) between changes in empirically observed and modelled estimates of clinical malaria were displayed by forest plots and examined by meta-regression. RESULTS Sixty-seven articles met our inclusion criteria representing 124 sites from 24 African countries. The single most important factor explaining the correlation between empirical observations and modelled predictions was the slope of empirically observed data over time (rho = - 0.989; 95% CI - 0.998, - 0.939; p < 0.001), i.e. steeper declines were associated with a stronger correlation between empirical observations and modelled predictions. Factors such as quality of study, reported measure of malaria and endemicity were only slightly predictive of such correlations. CONCLUSIONS In many locations, both local surveillance data and modelled estimates showed declines in malaria burden and hence similar trends. However, there was a weak association between individual surveillance datasets and the modelled predictions where stalling in progress or resurgence of malaria burden was empirically observed. Surveillance data were patchy, indicating a need for improved surveillance to strengthen both empiric reporting and modelled predictions.
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Affiliation(s)
- Alice Kamau
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | | | | | - Robert W Snow
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
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Nakakana UN, Mohammed IA, Onankpa BO, Jega RM, Jiya NM. A validation of the Malaria Atlas Project maps and development of a new map of malaria transmission in Sokoto, Nigeria: a cross-sectional study using geographic information systems. Malar J 2020; 19:149. [PMID: 32268904 PMCID: PMC7140379 DOI: 10.1186/s12936-020-03214-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 03/30/2020] [Indexed: 11/29/2022] Open
Abstract
Background Malaria remains a major cause of morbidity and mortality among children in Africa. There is inadequate information regarding malaria transmission-intensity in some of the worst-affected parts of sub-Saharan Africa (SSA). The Malaria Atlas Project (MAP) was developed in 2006, to project estimates of malaria transmission intensity where this data is not available, based on the vector behaviour for malaria. Data from malariometric studies globally were obtained and modelled to provide prevalence estimates. The sensitivity of these maps, however, reduces with unavailability of data. This necessitates a validation of these maps locally, and investigation into alternative methods of predicting prevalence to guide malaria control interventions and improve their efficiency and effectiveness. This study was conducted to compare the true estimates in Sokoto, Nigeria, with the MAP projections for north-western Nigeria, and it proposes an alternative way of mapping malaria intensity in Nigeria and beyond. Methods A malariometric survey was conducted including children aged 2–10 years in communities in Wamakko Local Government Area (LGA) of Sokoto State, Nigeria. Children had blood examinations for the presence of malaria parasitaemia and a physical examination for the signs of clinical malaria. All the sites from which children were included in the study were geo-located using a hand-held Global Positioning System (GPS) device and compared this to MAP maps of the same area. A mapping software was also used to generate a malaria prevalence map of the study area, considering the average flight distances of the vector. Results The prevalence among children 2 to 10 years was found to be 34.8% which was within the 30–40% projected prevalence for the study area by MAPs. However, it was much lower than the projection during the dry season (20.2%) and higher than the projected estimate during the rainy season (49.3%). There was monoparasitaemia of Plasmodium falciparum throughout the study area, although the study was not specifically designed to identify other species. The prevalence of parasitaemia and splenomegaly were similar when overall and when considered by age of the participants. The study also generated a map of malaria transmission, which mapped out areas where the prevalence was confirmed or likely to be to be within the range of 30–40%, based on the sites which constituted the study area for this study. Conclusion The study concludes that the prevalence of malaria and its transmission intensity in Sokoto are similar to Malaria Atlas Project predictions for the area and that, for malaria control planning purposes, the projections may be utilized, with more efforts at validation of the MAPs in other locations and terrains. Also, the vector behaviour may be used to map transmission of malaria and other vector-transmitted diseases, where this information is lacking.
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Affiliation(s)
- Usman Nasir Nakakana
- Department of Paediatrics, Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria. .,Medical Research Council, The Gambia at London School of Tropical Medicine and Hygiene, Fajara, The Gambia.
| | - Ismaila Ahmed Mohammed
- Department of Community Medicine, Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria
| | - B O Onankpa
- Department of Paediatrics, Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria
| | - Ridwan M Jega
- Department of Paediatrics, Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria
| | - Nma Muhammad Jiya
- Department of Paediatrics, Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria
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Kigozi SP, Kigozi RN, Epstein A, Mpimbaza A, Sserwanga A, Yeka A, Nankabirwa JI, Halliday K, Pullan RL, Rutazaana D, Sebuguzi CM, Opigo J, Kamya MR, Staedke SG, Dorsey G, Greenhouse B, Rodriguez-Barraquer I. Rapid shifts in the age-specific burden of malaria following successful control interventions in four regions of Uganda. Malar J 2020; 19:128. [PMID: 32228584 PMCID: PMC7106889 DOI: 10.1186/s12936-020-03196-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/20/2020] [Indexed: 12/17/2022] Open
Abstract
Background Malaria control using long-lasting insecticidal nets (LLINs) and indoor residual spraying of insecticide (IRS) has been associated with reduced transmission throughout Africa. However, the impact of transmission reduction on the age distribution of malaria cases remains unclear. Methods Over a 10-year period (January 2009 to July 2018), outpatient surveillance data from four health facilities in Uganda were used to estimate the impact of control interventions on temporal changes in the age distribution of malaria cases using multinomial regression. Interventions included mass distribution of LLINs at all sites and IRS at two sites. Results Overall, 896,550 patient visits were included in the study; 211,632 aged < 5 years, 171,166 aged 5–15 years and 513,752 > 15 years. Over time, the age distribution of patients not suspected of malaria and those malaria negative either declined or remained the same across all sites. In contrast, the age distribution of suspected and confirmed malaria cases increased across all four sites. In the two LLINs-only sites, the proportion of malaria cases in < 5 years decreased from 31 to 16% and 35 to 25%, respectively. In the two sites receiving LLINs plus IRS, these proportions decreased from 58 to 30% and 64 to 47%, respectively. Similarly, in the LLINs-only sites, the proportion of malaria cases > 15 years increased from 40 to 61% and 29 to 39%, respectively. In the sites receiving LLINs plus IRS, these proportions increased from 19 to 44% and 18 to 31%, respectively. Conclusions These findings demonstrate a shift in the burden of malaria from younger to older individuals following implementation of successful control interventions, which has important implications for malaria prevention, surveillance, case management and control strategies.
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Affiliation(s)
- Simon P Kigozi
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. .,Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.
| | - Ruth N Kigozi
- USAID's Malaria Action Program for Districts, PO Box 8045, Kampala, Uganda
| | - Adrienne Epstein
- Department of Epidemiology & Biostatistics, University of California, San Francisco, 550 16th Street, San Francisco, CA, 94158, USA
| | - Arthur Mpimbaza
- Child Health and Development Centre, Makerere University College of Health Sciences, Mulago Hospital Complex, PO Box 7072, Kampala, Uganda
| | - Asadu Sserwanga
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda
| | - Adoke Yeka
- School of Public Health, Makerere University College of Health Sciences, Mulago Hospital Complex, PO Box 7072, Kampala, Uganda
| | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,School of Medicine, Makerere University College of Health Sciences, Mulago Hospital Complex, PO Box 7072, Kampala, Uganda
| | - Katherine Halliday
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Rachel L Pullan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Damian Rutazaana
- National Malaria Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Catherine M Sebuguzi
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,National Malaria Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Jimmy Opigo
- National Malaria Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,School of Medicine, Makerere University College of Health Sciences, Mulago Hospital Complex, PO Box 7072, Kampala, Uganda
| | - Sarah G Staedke
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,Department of Clinical Research, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Grant Dorsey
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,Department of Medicine, University of California, San Francisco, 1001 Potrero Ave, SFGH Building 30, San Francisco, CA, 94110, USA
| | - Bryan Greenhouse
- Division of HIV, ID, and Global Medicine, University of California, San Francisco, 1001 Potrero Ave, SFGH, Building 3, San Francisco, CA, 94110, USA.,Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Isabel Rodriguez-Barraquer
- Division of HIV, ID, and Global Medicine, University of California, San Francisco, 1001 Potrero Ave, SFGH, Building 3, San Francisco, CA, 94110, USA
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Ouédraogo M, Kangoye DT, Samadoulougou S, Rouamba T, Donnen P, Kirakoya-Samadoulougou F. Malaria Case Fatality Rate among Children under Five in Burkina Faso: An Assessment of the Spatiotemporal Trends Following the Implementation of Control Programs. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E1840. [PMID: 32178354 PMCID: PMC7143776 DOI: 10.3390/ijerph17061840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/04/2020] [Accepted: 03/09/2020] [Indexed: 12/14/2022]
Abstract
Reducing the 2015 level of malaria mortality by 90% by 2030 is a goal set by the World Health Organization (WHO). In Burkina Faso, several malaria control programs proven to be effective were implemented over the last decade. In parallel, the progressive strengthening of the health surveillance system is generating valuable data, which represents a great opportunity for analyzing the trends in malaria burden and assessing the effect of these control programs. Complementary programs were rolled out at different time points and paces, and the present work aims at investigating both the spatial and temporal pattern of malaria case fatality rate (mCFR) by considering the effect of combining specific and unspecific malaria control programs. To this end, data on severe malaria cases and malaria deaths, aggregated at health district level between January 2013 and December 2018, were extracted from the national health data repository (ENDOS-BF). A Bayesian spatiotemporal zero-inflated Poisson model was fitted to quantify the strength of the association of malaria control programs with monthly mCFR trends at health district level. The model was adjusted for contextual variables. We found that monthly mCFR decreased from 2.0 (95% IC 1.9-2.1%) to 0.9 (95% IC 0.8-1.0%) deaths for 100 severe malaria cases in 2013 and 2018, respectively. Health districts with high mCFR were identified in the northern, northwestern and southwestern parts of the country. The availability of malaria rapid diagnosis tests (IRR: 0.54; CrI: 0.47, 0.62) and treatment (IRR: 0.50; CrI: 0.41, 0.61) were significantly associated with a reduction in the mCFR. The risk of dying from malaria was lower in the period after the free healthcare policy compared with the period before (IRR: 0.47; CrI: 0.38, 0.58). Our findings highlighted locations that are most in need of targeted interventions and the necessity to sustain and strengthen the launched health programs to further reduce the malaria deaths in Burkina Faso.
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Affiliation(s)
- Mady Ouédraogo
- Centre de Recherche en Epidémiologie, Biostatistiques et Recherche Clinique, Ecole de Santé Publique, Université Libre de Bruxelles, 1070 Brussels, Belgium; (M.O.); (T.R.); (P.D.)
- Institut de Recherche Santé et Sociétés, Faculté de Santé Publique, Université catholique de Louvain, 1200 Brussels, Belgium
- Institut National de la Statistique et de la Démographie [INSD], 01 BP 374 Ouagadougou 01, Burkina Faso
| | - David Tiga Kangoye
- Centre National de Recherche et de Formation sur le Paludisme [CNRFP], 01 BP 2208 Ouagadougou 101, Burkina Faso;
| | - Sékou Samadoulougou
- Evaluation Platform on Obesity Prevention, Quebec Heart and Lung Institute, Quebec, QC G1V 4G5, Canada;
- Centre for Research on Planning and Development (CRAD), Université Laval, Quebec, QC G1V 0A6, Canada
| | - Toussaint Rouamba
- Centre de Recherche en Epidémiologie, Biostatistiques et Recherche Clinique, Ecole de Santé Publique, Université Libre de Bruxelles, 1070 Brussels, Belgium; (M.O.); (T.R.); (P.D.)
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Centre National de la Recherche Scientifique et Technologique, 42 Avenue Kumda-Yonre, Ouagadougou, Kadiogo 11 BP 218 Ouagadougou CMS 11, Burkina Faso
| | - Philippe Donnen
- Centre de Recherche en Epidémiologie, Biostatistiques et Recherche Clinique, Ecole de Santé Publique, Université Libre de Bruxelles, 1070 Brussels, Belgium; (M.O.); (T.R.); (P.D.)
- Centre de Recherche en Politiques et systèmes de santé-Santé internationale, École de Santé Publique Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Fati Kirakoya-Samadoulougou
- Centre de Recherche en Epidémiologie, Biostatistiques et Recherche Clinique, Ecole de Santé Publique, Université Libre de Bruxelles, 1070 Brussels, Belgium; (M.O.); (T.R.); (P.D.)
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Masalu JP, Finda M, Killeen GF, Ngowo HS, Pinda PG, Okumu FO. Creating mosquito-free outdoor spaces using transfluthrin-treated chairs and ribbons. Malar J 2020; 19:109. [PMID: 32156280 PMCID: PMC7063784 DOI: 10.1186/s12936-020-03180-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 03/02/2020] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Residents of malaria-endemic communities spend several hours outdoors performing different activities, e.g. cooking, story-telling or eating, thereby exposing themselves to potentially-infectious mosquitoes. This compromises effectiveness of indoor interventions, notably long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS). This study characterized common peri-domestic spaces in rural south-eastern Tanzania, and assessed protective efficacy against mosquitoes of hessian fabric mats and ribbons treated with the spatial repellent, transfluthrin, and fitted to chairs and outdoor kitchens, respectively. METHODS Two hundred households were surveyed, and their most-used peri-domestic spaces physically characterized. Protective efficacies of locally-made transfluthrin-emanating chairs and hessian ribbons were tested in outdoor environments of 28 households in dry and wet seasons, using volunteer-occupied exposure-free double net traps. CDC light traps were used to estimate host-seeking mosquito densities within open-structure outdoor kitchens. Field-collected Anopheles arabiensis and Anopheles funestus mosquitoes were exposed underneath the chairs to estimate 24 h-mortality. Finally, The World Health Organization insecticide susceptibility tests were conducted on wild-caught Anopheles from the villages. RESULTS Approximately half (52%) of houses had verandas. Aside from these verandas, most houses also had peri-domestic spaces where residents stayed most times (67% of houses with verandas and 94% of non-veranda houses). Two-thirds of these spaces were sited under trees, and only one third (34.4%) were built-up. The outdoor structures were usually makeshift kitchens having roofs and partial walls. Transfluthrin-treated chairs reduced outdoor-biting An. arabiensis densities by 70-85%, while transfluthrin-treated hessian ribbons fitted to the outdoor kitchens caused 77-81% reduction in the general peri-domestic area. Almost all the field-collected An. arabiensis (99.4%) and An. funestus (100%) exposed under transfluthrin-treated chairs died. The An. arabiensis were susceptible to non-pyrethroids (pirimiphos methyl and bendiocarb), but resistant to pyrethroids commonly used on LLINs (deltamethrin and permethrin). CONCLUSION Most houses had actively-used peri-domestic outdoor spaces where exposure to mosquitoes occurred. The transfluthrin-treated chairs and ribbons reduced outdoor-biting malaria vectors in these peri-domestic spaces, and also elicited significant mortality among pyrethroid-resistant field-caught malaria vectors. These two new prototype formats for transfluthrin emanators, if developed further, may constitute new options for complementing LLINs and IRS with outdoor protection against malaria and other mosquito-borne pathogens in areas where peri-domestic human activities are common.
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Affiliation(s)
- John P Masalu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania.
- School of Life Science and Biotechnology, Nelson Mandela African Institution of Science and Technology, Arusha, United Republic of Tanzania.
| | - Marceline Finda
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Public Health, University of the Witwatersrand, Parktown, Johannesburg, Republic of South Africa
| | - Gerry F Killeen
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Halfan S Ngowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Polius G Pinda
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
| | - Fredros O Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Life Science and Biotechnology, Nelson Mandela African Institution of Science and Technology, Arusha, United Republic of Tanzania
- School of Public Health, University of the Witwatersrand, Parktown, Johannesburg, Republic of South Africa
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
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Hercik C, Cosmas L, Mogeni OD, Kohi W, Mfinanga S, Loffredo C, Montgomery JM. Health Beliefs and Patient Perspectives of Febrile Illness in Kilombero, Tanzania. Am J Trop Med Hyg 2020; 101:263-270. [PMID: 31115309 DOI: 10.4269/ajtmh.17-0862] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
This qualitative study assessed the knowledge and beliefs surrounding fever syndrome among adult febrile patients seeking health care in Kilombero, Tanzania. From June 11 to July 13, 2014, 10% of all adult (≥ 15 years) febrile patients enrolled in the larger syndromic study, who presented with an axillary temperature ≥ 37.5°C and symptom onset ≤ 5 days prior, were randomly selected to participate in an in-depth physician-patient interview, informed by Health Belief Model constructs. Interviews were audio recorded, translated, and transcribed. Transcripts were coded using NVivo Version 11.1, and the thematic content was analyzed by two separate researchers. Blood and nasopharyngeal/oralpharyngeal specimens were collected and analyzed using both acute febrile illness and respiratory TaqMan Array Cards for multipathogen detection of 56 potential causative agents. A total of 18 participants provided 188 discrete comments. When asked to speculate the causative agent of febrile illness, 33.3% cited malaria and the other 66.6% offered nonbiomedical responses, such as "mosquitoes" and "weather." Major themes emerging related to severity and susceptibility to health hazards included lack of bed net use, misconceptions about bed nets, and mosquito infestation. Certain barriers to treatment were cited, including dependence on traditional healers, high cost of drugs, and poor dispensary services. Overall, we demonstrate low concurrence in speculations of fever etiology according to patients, clinicians, and laboratory testing. Our findings contribute to the important, yet limited, base of knowledge surrounding patient risk perceptions of febrile illness and underscore the potential utility of community-based participatory research to inform disease control programs.
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Affiliation(s)
| | - Leonard Cosmas
- Division of Global Health Protection, Center for Global Health, US Centers for Disease Control and Prevention (US CDC), Nairobi, Kenya
| | - Ondari D Mogeni
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Wanze Kohi
- Muhimbili Research Centre, National Institute of Medical Research, Dar es Salaam, Tanzania
| | - Sayoki Mfinanga
- Muhimbili University of Health and Allied Science, Dar es Salaam, Tanzania.,Muhimbili Research Centre, National Institute of Medical Research, Dar es Salaam, Tanzania
| | - Christopher Loffredo
- Georgetown Lombardi Comprehensive Cancer Center, Georgetown University, Washington, District of Columbia
| | - Joel M Montgomery
- Division of Global Health Protection, Center for Global Health, US Centers for Disease Control and Prevention (US CDC), Nairobi, Kenya
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Furnival-Adams JEC, Camara S, Rowland M, Koffi AA, Ahoua Alou LP, Oumbouke WA, N'Guessan R. Indoor use of attractive toxic sugar bait in combination with long-lasting insecticidal net against pyrethroid-resistant Anopheles gambiae: an experimental hut trial in Mbé, central Côte d'Ivoire. Malar J 2020; 19:11. [PMID: 31910831 PMCID: PMC6947962 DOI: 10.1186/s12936-019-3095-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 12/26/2019] [Indexed: 11/23/2022] Open
Abstract
Background Indoor attractive toxic sugar bait (ATSB) has potential as a supplementary vector-control and resistance-management tool, offering an alternative mode of insecticide delivery to current core vector-control interventions, with potential to deliver novel insecticides. Given the high long-lasting insecticidal bed net (LLIN) coverage across Africa, it is crucial that the efficacy of indoor ATSB in combination with LLINs is established before it is considered for wider use in public health. Methods An experimental hut trial to evaluate the efficacy of indoor ATSB traps treated with 4% boric acid (BA ATSB) or 1% chlorfenapyr (CFP ATSB) in combination with untreated nets or LLINs (holed or intact), took place at the M’bé field station in central Côte d’Ivoire against pyrethroid resistant Anopheles gambiae sensu lato. Results The addition of ATSB to LLINs increased the mortality rates of wild pyrethroid-resistant An. gambiae from 19% with LLIN alone to 28% with added BA ATSB and to 39% with added CFP ATSB (p < 0.001). Anopheles gambiae mortality with combined ATSB and untreated net was similar to that of combined ATSB and LLIN regardless of which insecticide was used in the ATSB. The presence of holes in the LLIN did not significantly affect ATSB-induced An. gambiae mortality. Comparative tests against pyrethroid resistant and susceptible strains using oral application of ATSB treated with pyrethroid demonstrated 66% higher survival rate among pyrethroid-resistant mosquitoes. Conclusion Indoor ATSB traps in combination with LLINs enhanced the control of pyrethroid-resistant An. gambiae. However, many host-seeking An. gambiae entering experimental huts with indoor ATSB exited into the verandah trap without sugar feeding when restricted from a host by a LLIN. Although ATSB has potential for making effective use of classes of insecticide otherwise unsuited to vector control, it does not exempt potential selection of resistance via this route.
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Affiliation(s)
| | - Soromane Camara
- Vector Control Product Evaluation Centre (VCPEC), Institut Pierre Richet, Bouaké, Côte d'Ivoire
| | - Mark Rowland
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Alphonsine A Koffi
- Vector Control Product Evaluation Centre (VCPEC), Institut Pierre Richet, Bouaké, Côte d'Ivoire
| | - Ludovic P Ahoua Alou
- Vector Control Product Evaluation Centre (VCPEC), Institut Pierre Richet, Bouaké, Côte d'Ivoire
| | - Welbeck A Oumbouke
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK.,Vector Control Product Evaluation Centre (VCPEC), Institut Pierre Richet, Bouaké, Côte d'Ivoire
| | - Raphael N'Guessan
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK. .,Vector Control Product Evaluation Centre (VCPEC), Institut Pierre Richet, Bouaké, Côte d'Ivoire.
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Fu Y, Lu X, Zhu F, Zhao Y, Ding Y, Ye L, Guo B, Liu T, Xu W. Improving the immunogenicity and protective efficacy of a whole-killed malaria blood-stage vaccine by chloroquine. Parasite Immunol 2019; 42:e12682. [PMID: 31644820 DOI: 10.1111/pim.12682] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 10/12/2019] [Accepted: 10/21/2019] [Indexed: 12/15/2022]
Abstract
A whole-killed malaria blood-stage vaccine (WKV) is promising in reducing the morbidity and mortality of malaria patients, but its efficacy needs to be improved. We found that the antimalarial drug chloroquine could augment the protective efficacy of the WKV of Plasmodium yoelii. The direct antimalarial effect of chloroquine on parasites during immunization could be excluded, as the administration of chloroquine or chloroquine plus alum every two weeks had a slight effect on parasitemia, and an immunization with NP-KLH (4-hydroxy-3-nitrophenylacetyl Keyhole Limpet Hemocyanin) plus chloroquine could significantly promote the generation of NP-specific antibodies. Additionally, alum was required for chloroquine to augment the immunogenicity of the pRBC lysate. Chloroquine did not promote the parasite-specific CD4+ T-cell responses, but significantly enhanced the WKV-induced germinal centre B cell reactions, class-switch recombination and secretion of functionally protective antibodies to plasmodium. The elevated parasite-specific antibodies were demonstrated to largely contribute to the chloroquine-enhanced protective immunity. Thus, we report that chloroquine could be used as an adjuvant to enhance the protective immunity of WKVs through promoting humoral responses.
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Affiliation(s)
- Yong Fu
- Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xiao Lu
- Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Feng Zhu
- Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Yunxiang Zhao
- Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Yan Ding
- Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Lilin Ye
- Institute of Immunology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Bo Guo
- Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Taiping Liu
- Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Wenyue Xu
- Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China
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Nkwenti HE, Ngowe MN, Fokam P, Fonyuy JN, Atanga SN, Nkfusai NC, Yankam BM, Tsoka-Gwegweni JM, Cumber SN. The effect of subsidized malaria treatment among under-five children in the Buea Health District, Cameroon. Pan Afr Med J 2019; 33:152. [PMID: 31558949 PMCID: PMC6754831 DOI: 10.11604/pamj.2019.33.152.16832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 05/29/2019] [Indexed: 11/11/2022] Open
Abstract
Introduction Access to free diagnoses and treatments has been shown to be a major determinant in malaria control. The Cameroon government launched in 2011 and 2014 the exemption of the under-fives' simple and severe malaria treatment policy to increase access to health care and reduce inequality, so as to reduce the mortality related to malaria among the under-fives. This study assessed the effect of providing free malaria treatment in the Buea health district. Methods This retrospective and cross sectional study was carried out in the Buea health district. Aggregated monthly data from (2008-2010) before and (2012-2014) after the implementation of free malaria treatment was compared, to assess the attributable outcomes of free treatment. A semi-structure questionnaire was also used to assess barriers faced in providing free malaria treatment services by health care workers. Data was collected using a semi-structure questionnaire and a data review summary sheet. The data was analysed using Epi-Info 7, Excel and SPSS (Statistical Package for the Social Sciences) version 20.0 for Windows. All statistical tests were performed at 95% confidence interval (significance level of 0.05). Results Increase utilisation of health care; as general and malaria related consultations (by 5.7% (p=0.001) witnessed an increase after the implementation of free malaria treatment services. Severe malaria hospitalisation also increased, indicating that most caregivers used the health facility when complications had already set in, which could have led to no significant reduction in mortality due to malaria among under-five children (4.4%, p=0.533). Conclusion Utilisation of health care increased; as consultation and morbidity rate increased after the implementation of free malaria treatment services. Communication strategy should therefore be strengthened so as to better disseminate information, so as to enhance the effectiveness of the program. There is the need to make a large-scale study to assess the impact of subsidized malaria treatment.
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Affiliation(s)
- Hedwig Eposi Nkwenti
- Department of Public Health and Hygiene, Faculty of Health Sciences, University of Buea, Buea, Cameroon
| | - Marcelin Ngowe Ngowe
- Department of Public Health and Hygiene, Faculty of Health Sciences, University of Buea, Buea, Cameroon
| | - Pius Fokam
- Department of Public Health and Hygiene, Faculty of Health Sciences, University of Buea, Buea, Cameroon
| | - Joseph Nkfusai Fonyuy
- Department of Public Health and Hygiene, Faculty of Health Sciences, University of Buea, Buea, Cameroon
| | - Sylvester Ndeso Atanga
- Department of Public Health and Hygiene, Faculty of Health Sciences, University of Buea, Buea, Cameroon
| | - Ngwayu Claude Nkfusai
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Brenda Mbouamba Yankam
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Joyce Mahlako Tsoka-Gwegweni
- School of Nursing & Public Health, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa.,Faculty of Health Sciences, University of the Free State, Bloemfontein, South Africa
| | - Samuel Nambile Cumber
- Faculty of Health Sciences, University of the Free State, Bloemfontein, South Africa.,Section for Epidemiology and Social Medicine, Department of Public Health, Institute of Medicine (EPSO), The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.,School of Health Systems and Public Health, Faculty of Health Sciences, University of Pretoria Private Bag X323, Gezina, Pretoria, 0001, South Africa
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The Diversity of the Plasmodium falciparum K13 Propeller Domain Did Not Increase after Implementation of Artemisinin-Based Combination Therapy in Uganda. Antimicrob Agents Chemother 2019; 63:AAC.01234-19. [PMID: 31358588 DOI: 10.1128/aac.01234-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 07/08/2019] [Indexed: 12/15/2022] Open
Abstract
Artemisinin-based combination therapies (ACTs) are the standard of care to treat uncomplicated falciparum malaria. However, resistance to artemisinins, defined as delayed parasite clearance after therapy, has emerged in Southeast Asia, and the spread of resistance to sub-Saharan Africa could have devastating consequences. Artemisinin resistance has been associated in Southeast Asia with multiple nonsynonymous single nucleotide polymorphisms (NS-SNPs) in the propeller domain of the gene encoding the Plasmodium falciparum K13 protein (K13PD). Some K13PD NS-SNPs have been seen in Africa, but the relevance of these mutations is unclear. To assess whether ACT use has selected for specific K13PD mutations, we compared the K13PD genetic diversity in clinical isolates collected before and after the implementation of ACT use from seven sites across Uganda. We detected K13PD NS-SNPs in 16 of 683 (2.3%) clinical isolates collected between 1999 and 2004 and in 26 of 716 (3.6%) isolates collected between 2012 and 2016 (P = 0.16), representing a total of 29 different polymorphisms at 27 codons. Individual NS-SNPs were usually detected only once, and none were found in more than 0.7% of the isolates. Three SNPs (C469F, P574L, and A675V) associated with delayed clearance in Southeast Asia were seen in samples collected between 2012 and 2016, each in a single isolate. No differences in diversity following implementation of ACT use were found at any of the seven sites, nor was there evidence of selective pressures acting on the locus. Our results suggest that selection by ACTs is not impacting on K13PD diversity in Uganda.
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Surendra H, Wijayanti MA, Murhandarwati EH, Irnawati, Yuniarti T, Mardiati, Herdiana, Sumiwi ME, Hawley WA, Lobo NF, Cook J, Drakeley C, Supargiyono. Analysis of serological data to investigate heterogeneity of malaria transmission: a community-based cross-sectional study in an area conducting elimination in Indonesia. Malar J 2019; 18:227. [PMID: 31286973 PMCID: PMC6615161 DOI: 10.1186/s12936-019-2866-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 07/03/2019] [Indexed: 01/22/2023] Open
Abstract
Background Analysis of anti-malarial antibody responses has the potential to improve characterization of the variation in exposure to infection in low transmission settings, where conventional measures, such as entomological estimates and parasitaemia point prevalence become less sensitive and expensive to measure. This study evaluates the use of sero-epidemiological analysis to investigate heterogeneity of transmission in area conducting elimination in Indonesia. Methods Filter paper bloodspots and epidemiological data were collected through a community-based cross-sectional study conducted in two sub-districts in Sabang municipality, Aceh province, Indonesia in 2013. Antibody responses to merozoite surface protein 1 (MSP-119) and apical membrane antigen 1 (AMA-1) for Plasmodium falciparum and Plasmodium vivax were measured using indirect enzyme-linked immunosorbent assay (ELISA). Seroconversion rates (SCR) were estimated by fitting a simple reversible catalytic model to seroprevalence data for each antibody. Spatial analysis was performed using a Normal model (SaTScan v.9.4.2) to identify the clustering of higher values of household antibody responses. Multiple logistic regression was used to investigate factors associated with exposure. Results 1624 samples were collected from 605 households. Seroprevalence to any P. falciparum antigen was higher than to any P. vivax antigen, 6.9% (95% CI 5.8–8.2) vs 2.0% (95% CI 1.4–2.8). SCR estimates suggest that there was a significant change in P. falciparum transmission with no exposure seen in children under 5 years old. Plasmodium falciparum SCR in over 5 years old was 0.008 (95% CI 0.003–0.017) and 0.012 (95% CI 0.005–0.030) in Sukakarya and Sukajaya sub-districts, respectively. Clusters of exposure were detected for both P. falciparum and P. vivax, most of them in Sukajaya sub-district. Higher age, P. vivax seropositivity and use of long-lasting insecticide-treated bed net (LLIN) were associated with higher P. falciparum exposure. Conclusion Analysis of community-based serological data helps describe the level of transmission, heterogeneity and factors associated with malaria transmission in Sabang. This approach could be an important additional tool for malaria monitoring and surveillance in low transmission settings in Indonesia. Electronic supplementary material The online version of this article (10.1186/s12936-019-2866-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Henry Surendra
- Infection Biology Department, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK. .,Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia.
| | - Mahardika A Wijayanti
- Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia.,Department of Parasitology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia
| | - Elsa H Murhandarwati
- Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia.,Department of Parasitology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia
| | - Irnawati
- Sabang Municipal Health Office, Sabang, Aceh, Indonesia
| | | | - Mardiati
- Sabang Municipal Health Office, Sabang, Aceh, Indonesia
| | - Herdiana
- Child Survival and Development Cluster, UNICEF Aceh Field Office, Jakarta, Indonesia
| | - Maria E Sumiwi
- Child Survival and Development Cluster, UNICEF Aceh Field Office, Jakarta, Indonesia
| | - William A Hawley
- Child Survival and Development Cluster, UNICEF Indonesia Country Office, Jakarta, Indonesia
| | - Neil F Lobo
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Jackie Cook
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Chris Drakeley
- Infection Biology Department, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Supargiyono
- Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia.,Department of Parasitology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia
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Elliott RC, Smith DL, Echodu DC. Synergy and timing: a concurrent mass medical campaign predicted to augment indoor residual spraying for malaria. Malar J 2019; 18:160. [PMID: 31060554 PMCID: PMC6501353 DOI: 10.1186/s12936-019-2788-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 04/23/2019] [Indexed: 11/12/2022] Open
Abstract
Background Control programmes for high burden countries are tasked with charting effective multi-year strategies for malaria control within significant resource constraints. Synergies between different control tools, in which more than additive benefit accrues from interventions used together, are of interest because they may be used to obtain savings or to maximize health impact per expenditure. One commonly used intervention in sub-Saharan Africa is indoor residual spraying (IRS), typically deployed through a mass campaign. While possible synergies between IRS and long-lasting insecticide-treated nets (LLINs) have been investigated in multiple transmission settings, coordinated synergy between IRS and other mass medical distribution campaigns have not attracted much attention. Recently, a strong timing-dependent synergy between an IRS campaign and a mass drug administration (MDA) was theoretically quantified. These synergistic benefits likely differ across settings depending on transmission intensity and its overall seasonal pattern. Methods High coverage interventions are modelled in different transmission environments using two methods: a Ross–Macdonald model variant and openmalaria simulations. The impact of each intervention strategy was measured through its ability to prevent host infections over time, and the effects were compared to the baseline case of deploying interventions in isolation. Results By modelling IRS and MDA together and varying their deployment times, a strong synergy was found when the administered interventions overlapped. The added benefit of co-timed interventions was robust to differences in the models. In the Ross–Macdonald model, the impact compared was roughly double the sequential interventions in most transmission settings. Openmalaria simulations of this medical control augmentation of an IRS campaign show an even stronger response with the same timing relationship. Conclusions The strong synergies found for these control tools between the complementary interventions demonstrate a general feature of effective concurrent campaign-style vector and medical interventions. A mass treatment campaign is normally short-lived, especially in higher transmission settings. When co-timed, the rapid clearing of the host parasite reservoir via chemotherapy is protected from resurgence by the longer duration of the vector control. An effective synchronous treatment campaign has the potential to greatly augment the impact of indoor residual spraying. Mass screening and treatment (MSAT) with highly sensitive rapid diagnostic tests may demonstrate a comparable trend while mass LLIN campaigns may similarly coordinate with MDA/MSAT.
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Affiliation(s)
- Richard C Elliott
- Micron School of Materials Science and Engineering, Boise State University, Engineering Building, Suite 338, Boise, ID, 83725, USA. .,Pilgrim Africa, 115 N 85th St #202, Seattle, WA, 98103, USA.
| | - David L Smith
- Institute for Health Metrics and Evaluation, University of Washington, 2301 Fifth Ave., Suite 600, Seattle, WA, 98121, USA
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The impact of an insecticide treated bednet campaign on all-cause child mortality: A geospatial impact evaluation from the Democratic Republic of Congo. PLoS One 2019; 14:e0212890. [PMID: 30794694 PMCID: PMC6386397 DOI: 10.1371/journal.pone.0212890] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/11/2019] [Indexed: 11/19/2022] Open
Abstract
Objective To test the impact of a nationwide Long-Lasting Insecticidal Nets [LLINs] distribution program in the Democratic Republic of Congo [DRC] on all-cause under-five child mortality exploiting subnational variation in malaria endemicity and the timing in the scale-up of the program across provinces. Design Geospatial Impact Evaluation using a difference-in-differences approach. Setting Democratic Republic of the Congo. Participants 52,656 children sampled in the 2007 and 2013/2014 DRC Demographic and Health Surveys. Interventions The analysis provides plausibly causal estimates of both average treatment effects of the LLIN distribution campaign and geospatial heterogeneity in these effects based on malaria endemicity. It compares the under-five, all-cause mortality for children pre- and post-LLIN campaign relative to children in those areas that had not yet been exposed to the campaign using a difference-in-differences model and controlling for year- and province-fixed effects, and province-level trends in mortality. Results We find that the campaign led to a 41% decline [3.7 percentage points, 95% CI 1.3 to 6.0] in under-5 mortality risk among children living in rural areas with malaria ecology above the sample median. Results were robust to controlling for household assets and the presence of other health aid programs. No effect was detected in children living in areas with malaria ecology below the median. Conclusion The findings of this paper make important contributions to the evidence base for the effectiveness of large scale-national LLIN campaigns against malaria. We found that the program was effective in areas of the DRC with the highest underlying risk of malaria. Targeting bednets to areas with greatest underlying risk for malaria may help to increase the efficiency of increasingly limited malaria resources but should be balanced against other malaria control concerns.
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