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Sendor R, Banek K, Kashamuka MM, Mvuama N, Bala JA, Nkalani M, Kihuma G, Atibu J, Thwai KL, Svec WM, Goel V, Nseka T, Lin JT, Bailey JA, Emch M, Carrel M, Juliano JJ, Tshefu A, Parr JB. Epidemiology of Plasmodium malariae and Plasmodium ovale spp. in Kinshasa Province, Democratic Republic of Congo. Nat Commun 2023; 14:6618. [PMID: 37857597 PMCID: PMC10587068 DOI: 10.1038/s41467-023-42190-w] [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: 04/06/2023] [Accepted: 10/03/2023] [Indexed: 10/21/2023] Open
Abstract
Reports suggest non-falciparum species are an underappreciated cause of malaria in sub-Saharan Africa but their epidemiology is ill-defined, particularly in highly malaria-endemic regions. We estimated incidence and prevalence of PCR-confirmed non-falciparum and Plasmodium falciparum malaria infections within a longitudinal study conducted in Kinshasa, Democratic Republic of Congo (DRC) between 2015-2017. Children and adults were sampled at biannual household surveys and routine clinic visits. Among 9,089 samples from 1,565 participants, incidences of P. malariae, P. ovale spp., and P. falciparum infections by 1-year were 7.8% (95% CI: 6.4%-9.1%), 4.8% (95% CI: 3.7%-5.9%) and 57.5% (95% CI: 54.4%-60.5%), respectively. Non-falciparum prevalences were higher in school-age children, rural and peri-urban sites, and P. falciparum co-infections. P. falciparum remains the primary driver of malaria in the DRC, though non-falciparum species also pose an infection risk. As P. falciparum interventions gain traction in high-burden settings, continued surveillance and improved understanding of non-falciparum infections are warranted.
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Affiliation(s)
- Rachel Sendor
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Kristin Banek
- Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Melchior M Kashamuka
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Nono Mvuama
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Joseph A Bala
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Marthe Nkalani
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Georges Kihuma
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Joseph Atibu
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Kyaw L Thwai
- Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - W Matthew Svec
- University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Varun Goel
- Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tommy Nseka
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Jessica T Lin
- Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Division of Infectious Diseases, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jeffrey A Bailey
- Department of Pathology and Laboratory Medicine and Center for Computational Molecular Biology, Brown University, Providence, RI, USA
| | - Michael Emch
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Margaret Carrel
- Department of Geographical and Sustainability Sciences, University of Iowa, Iowa City, IA, USA
| | - Jonathan J Juliano
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Division of Infectious Diseases, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Antoinette Tshefu
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Jonathan B Parr
- Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Division of Infectious Diseases, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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Hollingsworth BD, Sandborn H, Baguma E, Ayebare E, Ntaro M, Mulogo EM, Boyce RM. Comparing field-collected versus remotely-sensed variables to model malaria risk in the highlands of western Uganda. Malar J 2023; 22:197. [PMID: 37365595 PMCID: PMC10294526 DOI: 10.1186/s12936-023-04628-w] [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] [Accepted: 06/16/2023] [Indexed: 06/28/2023] Open
Abstract
BACKGROUND Malaria risk is not uniform across relatively small geographic areas, such as within a village. This heterogeneity in risk is associated with factors including demographic characteristics, individual behaviours, home construction, and environmental conditions, the importance of which varies by setting, making prediction difficult. This study attempted to compare the ability of statistical models to predict malaria risk at the household level using either (i) free easily-obtained remotely-sensed data or (ii) results from a resource-intensive household survey. METHODS The results of a household malaria survey conducted in 3 villages in western Uganda were combined with remotely-sensed environmental data to develop predictive models of two outcomes of interest (1) a positive ultrasensitive rapid diagnostic test (uRDT) and (2) inpatient admission for malaria within the last year. Generalized additive models were fit to each result using factors from the remotely-sensed data, the household survey, or a combination of both. Using a cross-validation approach, each model's ability to predict malaria risk for out-of-sample households (OOS) and villages (OOV) was evaluated. RESULTS Models fit using only environmental variables provided a better fit and higher OOS predictive power for uRDT result (AIC = 362, AUC = 0.736) and inpatient admission (AIC = 623, AUC = 0.672) compared to models using household variables (uRDT AIC = 376, Admission AIC = 644, uRDT AUC = 0.667, Admission AUC = 0.653). Combining the datasets did not result in a better fit or higher OOS predictive power for uRDT results (AIC = 367, AUC = 0.671), but did for inpatient admission (AIC = 615, AUC = 0.683). Household factors performed best when predicting OOV uRDT results (AUC = 0.596) and inpatient admission (AUC = 0.553), but not much better than a random classifier. CONCLUSIONS These results suggest that residual malaria risk is driven more by the external environment than home construction within the study area, possibly due to transmission regularly occurring outside of the home. Additionally, they suggest that when predicting malaria risk the benefit may not outweigh the high costs of attaining detailed information on household predictors. Instead, using remotely-sensed data provides an equally effective, cost-efficient alternative.
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Affiliation(s)
| | - Hilary Sandborn
- Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Emmanuel Baguma
- Department of Community Health, Faculty of Medicine, Mbarara University of Science & Technology, Mbarara, Uganda
| | - Emmanuel Ayebare
- Department of Community Health, Faculty of Medicine, Mbarara University of Science & Technology, Mbarara, Uganda
| | - Moses Ntaro
- Department of Community Health, Faculty of Medicine, Mbarara University of Science & Technology, Mbarara, Uganda
| | - Edgar M Mulogo
- Department of Community Health, Faculty of Medicine, Mbarara University of Science & Technology, Mbarara, Uganda
| | - Ross M Boyce
- Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Obame-Nkoghe J, Makanga BK, Zongo SB, Koumba AA, Komba P, Longo-Pendy NM, Mounioko F, Akone-Ella R, Nkoghe-Nkoghe LC, Ngangue-Salamba MF, Yangari P, Aboughe-Angone S, Fournet F, Kengne P, Paupy C. Urban Green Spaces and Vector-Borne Disease Risk in Africa: The Case of an Unclean Forested Park in Libreville (Gabon, Central Africa). INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:ijerph20105774. [PMID: 37239503 DOI: 10.3390/ijerph20105774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 04/12/2023] [Accepted: 04/14/2023] [Indexed: 05/28/2023]
Abstract
In Africa, vector-borne diseases are a major public health issue, especially in cities. Urban greening is increasingly considered to promote inhabitants' well-being. However, the impact of urban green spaces on vector risk remains poorly investigated, particularly urban forests in poor hygienic conditions. Therefore, using larval sampling and human landing catches, this study investigated the mosquito diversity and the vector risk in a forest patch and its inhabited surroundings in Libreville, Gabon, central Africa. Among the 104 water containers explored, 94 (90.4%) were artificial (gutters, used tires, plastic bottles) and 10 (9.6%) were natural (puddles, streams, tree holes). In total, 770 mosquitoes belonging to 14 species were collected from such water containers (73.1% outside the forested area). The mosquito community was dominated by Aedes albopictus (33.5%), Culex quinquefasciatus (30.4%), and Lutzia tigripes (16.5%). Although mosquito diversity was almost double outside compared to inside the forest (Shannon diversity index: 1.3 vs. 0.7, respectively), the species relative abundance (Morisita-Horn index = 0.7) was similar. Ae. albopictus (86.1%) was the most aggressive species, putting people at risk of Aedes-borne viruses. This study highlights the importance of waste pollution in urban forested ecosystems as a potential driver of mosquito-borne diseases.
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Affiliation(s)
- Judicaël Obame-Nkoghe
- Laboratoire de Biologie Moléculaire et Cellulaire, Département de Biologie, Université des Sciences et Techniques de Masuku (USTM), Franceville BP 941, Gabon
- Unité de Recherche en Écologie de la Santé, Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville BP 769, Gabon
| | - Boris Kevin Makanga
- Institut de Recherche en Écologie Tropicale (IRET/CENAREST), Libreville BP 13354, Gabon
| | - Sylvie Brizard Zongo
- Laboratoire de Biologie Moléculaire et Cellulaire, Département de Biologie, Université des Sciences et Techniques de Masuku (USTM), Franceville BP 941, Gabon
- Département Faune et Aires Protégées, École Nationale des Eaux et Forêts (ENEF), Libreville BP 3960, Gabon
| | - Aubin Armel Koumba
- Institut de Recherche en Écologie Tropicale (IRET/CENAREST), Libreville BP 13354, Gabon
| | - Prune Komba
- Unité de Recherche GéoHydrosystèmes Continentaux (UR GéHCo), Département Géosciences et Environnement, Université de Tours, 37000 Tours, France
| | - Neil-Michel Longo-Pendy
- Unité de Recherche en Écologie de la Santé, Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville BP 769, Gabon
| | - Franck Mounioko
- Laboratoire de Biologie Moléculaire et Cellulaire, Département de Biologie, Université des Sciences et Techniques de Masuku (USTM), Franceville BP 941, Gabon
- Unité de Recherche en Écologie de la Santé, Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville BP 769, Gabon
| | - Rodolphe Akone-Ella
- Unité de Recherche en Écologie de la Santé, Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville BP 769, Gabon
| | - Lynda Chancelya Nkoghe-Nkoghe
- Unité de Recherche en Écologie de la Santé, Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville BP 769, Gabon
| | - Marc-Flaubert Ngangue-Salamba
- Unité de Recherche en Écologie de la Santé, Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville BP 769, Gabon
| | - Patrick Yangari
- Unité de Recherche en Écologie de la Santé, Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville BP 769, Gabon
| | - Sophie Aboughe-Angone
- Institut de Pharmacopée et de Médecine Traditionnelle (IPHAMETRA), Libreville BP 1156, Gabon
| | - Florence Fournet
- Unité Mixte de Recherche Maladies Infectieuses et Vecteurs, Écologie, Génétique, Évolution et Contrôle (MIVEGEC), Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), 34193 Montpellier, France
| | - Pierre Kengne
- Unité de Recherche en Écologie de la Santé, Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville BP 769, Gabon
- Unité Mixte de Recherche Maladies Infectieuses et Vecteurs, Écologie, Génétique, Évolution et Contrôle (MIVEGEC), Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), 34193 Montpellier, France
| | - Christophe Paupy
- Unité Mixte de Recherche Maladies Infectieuses et Vecteurs, Écologie, Génétique, Évolution et Contrôle (MIVEGEC), Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), 34193 Montpellier, France
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Sendor R, Banek K, Kashamuka MM, Mvuama N, Bala JA, Nkalani M, Kihuma G, Atibu J, Thwai KL, Svec WM, Goel V, Nseka T, Lin JT, Bailey JA, Emch M, Carrel M, Juliano JJ, Tshefu A, Parr JB. Epidemiology of Plasmodium malariae and Plasmodium ovale spp. in a highly malaria-endemic country: a longitudinal cohort study in Kinshasa Province, Democratic Republic of Congo. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.04.20.23288826. [PMID: 37790376 PMCID: PMC10543032 DOI: 10.1101/2023.04.20.23288826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Background Increasing reports suggest that non-falciparum species are an underappreciated cause of malaria in sub-Saharan Africa, but their epidemiology is not well-defined. This is particularly true in regions of high P. falciparum endemicity such as the Democratic Republic of Congo (DRC), where 12% of the world's malaria cases and 13% of deaths occur. Methods and Findings The cumulative incidence and prevalence of P. malariae and P. ovale spp. infection detected by real-time PCR were estimated among children and adults within a longitudinal study conducted in seven rural, peri-urban, and urban sites from 2015-2017 in Kinshasa Province, DRC. Participants were sampled at biannual household survey visits (asymptomatic) and during routine health facility visits (symptomatic). Participant-level characteristics associated with non-falciparum infections were estimated for single- and mixed-species infections. Among 9,089 samples collected from 1,565 participants over a 3-year period, the incidence of P. malariae and P. ovale spp. infection was 11% (95% CI: 9%-12%) and 7% (95% CI: 5%-8%) by one year, respectively, compared to a 67% (95% CI: 64%-70%) one-year cumulative incidence of P. falciparum infection. Incidence continued to rise in the second year of follow-up, reaching 26% and 15% in school-age children (5-14yo) for P. malariae and P. ovale spp., respectively. Prevalence of P. malariae, P. ovale spp., and P. falciparum infections during household visits were 3% (95% CI: 3%-4%), 1% (95% CI: 1%-2%), and 35% (95% CI: 33%-36%), respectively. Non-falciparum malaria was more prevalent in rural and peri-urban vs. urban sites, in school-age children, and among those with P. falciparum co-infection. A crude association was detected between P. malariae and any anemia in the symptomatic clinic population, although this association did not hold when stratified by anemia severity. No crude associations were detected between non-falciparum infection and fever prevalence. Conclusions P. falciparum remains the primary driver of malaria morbidity and mortality in the DRC. However, non-falciparum species also pose an infection risk across sites of varying urbanicity and malaria endemicity within Kinshasa, DRC, particularly among children under 15 years of age. As P. falciparum interventions gain traction in high-burden settings like the DRC, continued surveillance and improved understanding of non-falciparum infections are warranted.
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Affiliation(s)
- Rachel Sendor
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Kristin Banek
- Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | | | - Nono Mvuama
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Joseph A. Bala
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Marthe Nkalani
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Georges Kihuma
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Joseph Atibu
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Kyaw L. Thwai
- Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - W. Matthew Svec
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Varun Goel
- Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Tommy Nseka
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Jessica T. Lin
- Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Division of Infectious Diseases, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Jeffrey A. Bailey
- Department of Pathology and Laboratory Medicine and Center for Computational Molecular Biology, Brown University, Providence, Rhode Island, United States of America
| | - Michael Emch
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Margaret Carrel
- Department of Geographical and Sustainability Sciences, University of Iowa, Iowa City, Iowa, United States of America
| | - Jonathan J. Juliano
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Division of Infectious Diseases, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Antoinette Tshefu
- Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Jonathan B. Parr
- Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Division of Infectious Diseases, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
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Ullah W, Yen TY, Niaz S, Nasreen N, Tsai YF, Rodriguez-Vivas RI, Khan A, Tsai KH. Distribution and Risk of Cutaneous Leishmaniasis in Khyber Pakhtunkhwa, Pakistan. Trop Med Infect Dis 2023; 8:tropicalmed8020128. [PMID: 36828544 PMCID: PMC9962270 DOI: 10.3390/tropicalmed8020128] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/16/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
Cutaneous leishmaniasis (CL) is a zoonotic infection caused by obligate intracellular protozoa of the genus Leishmania. This study aimed to investigate CL in Khyber Pakhtunkhwa, Pakistan and to estimate the risk of epidemics. Clinico-epidemiological data of 3188 CL patients were collected from health facilities in 2021. Risk factors were analyzed using the chi-square test. ArcGIS V.10.7.1 was applied for spatial analysis. The association between CL occurrence and climatic variables was examined by Bayesian geostatistical analysis. The clinical data revealed males or individuals younger than 20 years old were more affected. Most patients presented with a single lesion, and the face was the most attacked body part. CL was prevalent in the southern region in winter. A proportional symbol map, a choropleth map, and a digital elevation model map were built to show the distribution of CL. Focal transmission was predicted by inverse distance weighting interpolation. Cluster and outlier analysis identified clusters in Bannu, Dir Lower, and Mardan, and hotspot analysis suggested Bannu as a high-risk foci. Bayesian geostatistical analysis indicated that increasing precipitation and temperature as well as low altitudes were associated with CL infection. The study has provided important information for public health sectors to develop intervention strategies for future CL epidemics.
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Affiliation(s)
- Wasia Ullah
- Department of Zoology, Abdul Wali Khan University, Mardan 23300, Khyber Pakhtunkhwa, Pakistan
| | - Tsai-Ying Yen
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei 100025, Taiwan
| | - Sadaf Niaz
- Department of Zoology, Abdul Wali Khan University, Mardan 23300, Khyber Pakhtunkhwa, Pakistan
| | - Nasreen Nasreen
- Department of Zoology, Abdul Wali Khan University, Mardan 23300, Khyber Pakhtunkhwa, Pakistan
| | - Yu-Feng Tsai
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei 100025, Taiwan
| | - Roger Ivan Rodriguez-Vivas
- Facultad de Medicina Veterinaria y Zootecnia, Campus de Ciencias Biologicas y Agropecuarias, Universidad Autonoma de Yucatán, Km 15.5 Carretera Mérida–Xmatkuil, Merida 97100, Yucatan, Mexico
| | - Adil Khan
- Department of Botany/Zoology, Bacha Khan University, Charsadda 24420, Khyber Pakhtunkhwa, Pakistan
- Correspondence: (A.K.); (K.-H.T.)
| | - Kun-Hsien Tsai
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei 100025, Taiwan
- Department of Public Health, College of Public Health, National Taiwan University, Taipei 100025, Taiwan
- Correspondence: (A.K.); (K.-H.T.)
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Weber AC, Bogler L, Vollmer S, Simen-Kapeu A, Ekpini RE, Zagre NM. The wealth gradient in diarrhoea, acute respiratory infections, and malaria in childhood over time: A descriptive analysis using DHS and MICS from Western and Central Africa between 1995 and 2017. J Glob Health 2021; 11:13009. [PMID: 34484716 PMCID: PMC8397329 DOI: 10.7189/jogh.11.13009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND While the prevalence of childhood diseases and related mortality have been decreasing over the past decades, progress has been unequally distributed. The poorest households often carry the highest disease burden. As morbidity and mortality also decline most slowly among children of the poorest households, socioeconomic status may become a more relevant risk factor for childhood diseases. METHODS We analysed the association between socioeconomic status and highly prevalent childhood diseases, specifically diarrhoea, acute respiratory infections (ARI), and malaria, and how this association changed over time. For this observational study, we used repeated cross-sectional data, namely all available Demographic and Health Surveys as well as Multi-Indicator Cluster Surveys from Western and Central Africa between 1995 and 2017. We estimated the predicted prevalence of each disease for the entire region in three time periods. We repeated the analysis separately for each country to highlight heterogeneity between countries. RESULTS A notable wealth gradient can be seen in the prevalence rates of diarrhoea, ARI, and malaria in Western and Central Africa. Children in the poorest quartile have a much higher morbidity than children in the richest quartile and have experienced a considerably slower decline in prevalence rates. In the period 2010-2017, predicted prevalence of diarrhoea was 17.5% for children in the poorest quartile and 12.5% for children in the richest quartile. Similarly, the predicted prevalence was 11.1% and 8.6% for ARI, and 54.1% and 24.4% for malaria in endemic countries. The pattern does not differ between boys and girls. While exact prevalence rates vary between countries, only few countries have seen a decline in the wealth gradient for childhood diseases. CONCLUSIONS The increasing wealth gradient in health raises concerns of increasing inequality that goes beyond wealth. It suggests a need to further improve targeting of health programmes. Moreover, these programmes should be adapted to address the interlinked challenges which burden the poorest households.
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Affiliation(s)
- Ann-Charline Weber
- Department of Economics and Centre for Modern Indian Studies, University of Göttingen, Göttingen, Germany
| | - Lisa Bogler
- Department of Economics and Centre for Modern Indian Studies, University of Göttingen, Göttingen, Germany
| | - Sebastian Vollmer
- Department of Economics and Centre for Modern Indian Studies, University of Göttingen, Göttingen, Germany
| | - Aline Simen-Kapeu
- United Nations Children’s Fund (UNICEF), West and Central Africa Regional Office, Dakar, Senegal
| | - Rene Ehounou Ekpini
- United Nations Children’s Fund (UNICEF), West and Central Africa Regional Office, Dakar, Senegal
| | - Noel Marie Zagre
- UNICEF Area Representative for Gabon and São Tomé and Príncipe and to the ECCAS, Libreville, Gabon
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Flavio A, Cedric Y, Nadia NAC, Payne VK. Malaria and Helminth Coinfection among Children at the Douala Gyneco-Obstetric and Pediatric Hospital. J Trop Med 2021; 2021:3702693. [PMID: 34306100 PMCID: PMC8266473 DOI: 10.1155/2021/3702693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/24/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Malaria and helminth infections are major public health issues in sub-Saharan Africa including Cameroon. This study was aimed at determining the prevalence and risk factors associated with malaria and helminth coinfection among children in the Douala Gyneco-Obstetric and Pediatric Hospital (HGOPED) in Douala, southwestern Cameroon. Material and Methods. The study was a hospital-based cross-sectional study that took place from January to July 2020 where 203 children were involved. Blood samples were collected from the children and thick blood smears were prepared and examined microscopically for malaria parasites. Stool samples were also collected and examined through the Kato-Katz technique for the identification of helminth eggs. Demographic and socioeconomic data and information of participant's knowledge on the transmission of malaria and helminth infections were collected with the use of a well-structured questionnaire. RESULTS The overall prevalence of P. falciparum infection was 28.8%, while the overall prevalence of helminth was 9.36%. The only species of helminth identified were Ascaris lumbricoides and Trichuris trichiura with a prevalence of 4.26% and 2.95%, respectively, and mixed infection of both A. lumbricoides and T. trichiura with a prevalence of 1.47%. Coinfection of malaria and helminth was observed with a prevalence of 6.90%. Associations of malaria-helminth coinfection with age groups, parent's educational level, type of latrine, and source of water factors were not statistically significant (p > 0.05), while the prevalence of the coinfection with respect to parent's occupation, presence of stagnant water around homes, washing of hands after using the toilet, and washing of fruits before eating was statistically significant (p < 0.05). CONCLUSION The findings suggest that helminths and malaria infections tend to occur in children. Not washing hands after using the toilet, not washing fruits before eating, the presence of stagnant water around homes, and parents' occupation were found to be strongly associated with coinfection. Health education on the importance of better sewage disposal, draining of stagnant water around homes, and other sanitary practices is recommended.
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Affiliation(s)
- Ashungafack Flavio
- Department of Animal Biology, Faculty of Science, University of Dschang, P. O. Box 067, Dschang, Cameroon
| | - Yamssi Cedric
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Bamenda, P. O. Box 39, Bambili, Cameroon
| | - Noumedem Anangmo Christelle Nadia
- Department of Microbiology, Hematology and Immunology Faculty of Medicine and Pharmaceutical Sciences, University of Dschang, P. O. Box 96, Dschang, Cameroon
| | - Vincent Khan Payne
- Department of Animal Biology, Faculty of Science, University of Dschang, P. O. Box 067, Dschang, Cameroon
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8
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Smith JL, Mumbengegwi D, Haindongo E, Cueto C, Roberts KW, Gosling R, Uusiku P, Kleinschmidt I, Bennett A, Sturrock HJ. Malaria risk factors in northern Namibia: The importance of occupation, age and mobility in characterizing high-risk populations. PLoS One 2021; 16:e0252690. [PMID: 34170917 PMCID: PMC8232432 DOI: 10.1371/journal.pone.0252690] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/20/2021] [Indexed: 11/19/2022] Open
Abstract
In areas of low and unstable transmission, malaria cases occur in populations with lower access to malaria services and interventions, and in groups with specific malaria risk exposures often away from the household. In support of the Namibian National Vector Borne Disease Program's drive to better target interventions based upon risk, we implemented a health facility-based case control study aimed to identify risk factors for symptomatic malaria in Zambezi Region, northern Namibia. A total of 770 febrile individuals reporting to 6 health facilities and testing positive by rapid diagnostic test (RDT) between February 2015 and April 2016 were recruited as cases; 641 febrile individuals testing negative by RDT at the same health facilities through June 2016 were recruited as controls. Data on socio-demographics, housing construction, overnight travel, use of malaria prevention and outdoor behaviors at night were collected through interview and recorded on a tablet-based questionnaire. Remotely-sensed environmental data were extracted for geo-located village residence locations. Multivariable logistic regression was conducted to identify risk factors and latent class analyses (LCA) used to identify and characterize high-risk subgroups. The majority of participants (87% of cases and 69% of controls) were recruited during the 2016 transmission season, an outbreak year in Southern Africa. After adjustment, cases were more likely to be cattle herders (Adjusted Odds Ratio (aOR): 4.46 95%CI 1.05-18.96), members of the police or other security personnel (aOR: 4.60 95%CI: 1.16-18.16), and pensioners/unemployed persons (aOR: 2.25 95%CI 1.24-4.08), compared to agricultural workers (most common category). Children (aOR 2.28 95%CI 1.13-4.59) and self-identified students were at higher risk of malaria (aOR: 4.32 95%CI 2.31-8.10). Other actionable risk factors for malaria included housing and behavioral characteristics, including traditional home construction and sleeping in an open structure (versus modern structure: aOR: 2.01 95%CI 1.45-2.79 and aOR: 4.76 95%CI: 2.14-10.57); cross border travel in the prior 30 days (aOR: 10.55 95%CI 2.94-37.84); and outdoor agricultural work at night (aOR: 2.09 95%CI 1.12-3.87). Malaria preventive activities were all protective and included personal use of an insecticide treated net (ITN) (aOR: 0.61 95%CI 0.42-0.87), adequate household ITN coverage (aOR: 0.63 95%CI 0.42-0.94), and household indoor residual spraying (IRS) in the past year (versus never sprayed: (aOR: 0.63 95%CI 0.44-0.90). A number of environmental factors were associated with increased risk of malaria, including lower temperatures, higher rainfall and increased vegetation for the 30 days prior to diagnosis and residing more than 5 minutes from a health facility. LCA identified six classes of cases, with class membership strongly correlated with occupation, age and select behavioral risk factors. Use of ITNs and IRS coverage was similarly low across classes. For malaria elimination these high-risk groups will need targeted and tailored intervention strategies, for example, by implementing alternative delivery methods of interventions through schools and worksites, as well as the use of specific interventions that address outdoor transmission.
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Affiliation(s)
- Jennifer L. Smith
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Davis Mumbengegwi
- Multidisciplinary Research Centre, University of Namibia, Windhoek, Namibia
| | - Erastus Haindongo
- School of Medicine, Faculty of Health Sciences, University of Namibia, Windhoek, Namibia
| | - Carmen Cueto
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Kathryn W. Roberts
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Roly Gosling
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Petrina Uusiku
- National Ministry of Health and Social Services, Windhoek, Namibia
| | - Immo Kleinschmidt
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Hugh J. Sturrock
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
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9
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Deutsch-Feldman M, Brazeau NF, Parr JB, Thwai KL, Muwonga J, Kashamuka M, Tshefu Kitoto A, Aydemir O, Bailey JA, Edwards JK, Verity R, Emch M, Gower EW, Juliano JJ, Meshnick SR. Spatial and epidemiological drivers of Plasmodium falciparum malaria among adults in the Democratic Republic of the Congo. BMJ Glob Health 2021; 5:bmjgh-2020-002316. [PMID: 32601091 PMCID: PMC7326263 DOI: 10.1136/bmjgh-2020-002316] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/22/2020] [Accepted: 04/25/2020] [Indexed: 11/17/2022] Open
Abstract
Background Adults are frequently infected with malaria and may serve as a reservoir for further transmission, yet we know relatively little about risk factors for adult infections. In this study, we assessed malaria risk factors among adults using samples from the nationally representative, cross-sectional 2013–2014 Demographic and Health Survey (DHS) conducted in the Democratic Republic of the Congo (DRC). We further explored differences in risk factors by urbanicity. Methods Plasmodium falciparum infection was determined by PCR. Covariates were drawn from the DHS to model individual, community and environmental-level risk factors for infection. Additionally, we used deep sequencing data to estimate the community-level proportions of drug-resistant infections and included these estimates as potential risk factors. All identified factors were assessed for differences in associations by urbanicity. Results A total of 16 126 adults were included. Overall prevalence of malaria was 30.3% (SE=1.1) by PCR; province-level prevalence ranged from 6.7% to 58.3%. Only 17% of individuals lived in households with at least one bed-net for every two people, as recommended by the WHO. Protective factors included increasing within-household bed-net coverage (Prevalence Ratio=0.85, 95% CI=0.76–0.95) and modern housing (PR=0.58, 95% CI=0.49–0.69). Community-level protective factors included increased median wealth (PR=0.87, 95% CI=0.83–0.92). Education, wealth, and modern housing showed protective associations in cities but not in rural areas. Conclusions The DRC continues to suffer from a high burden of malaria; interventions that target high-risk groups and sustained investment in malaria control are sorely needed. Areas of high prevalence should be prioritised for interventions to target the largest reservoirs for further transmission.
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Affiliation(s)
- Molly Deutsch-Feldman
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Nicholas F Brazeau
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Jonathan B Parr
- Division of Infectious Diseases, Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Kyaw L Thwai
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Jeremie Muwonga
- National AIDS Control Program, Kinshasa, Congo (the Democratic Republic)
| | - Melchior Kashamuka
- School of Public Health, University of Kinshasa Faculty of Medicine, Kinshasa, Congo (the Democratic Republic)
| | - Antoinette Tshefu Kitoto
- School of Public Health, University of Kinshasa Faculty of Medicine, Kinshasa, Congo (the Democratic Republic)
| | - Ozkan Aydemir
- Department of Pathology and Laboratory Medicine, Brown University Warren Alpert Medical School, Providence, Rhode Island, USA
| | - Jeffrey A Bailey
- Department of Pathology and Laboratory Medicine, Brown University Warren Alpert Medical School, Providence, Rhode Island, USA
| | - Jessie K Edwards
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Robert Verity
- Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Michael Emch
- Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Emily W Gower
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Jonathan J Juliano
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Division of Infectious Diseases, Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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10
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Zeb I, Qureshi NA, Shaheen N, Zafar MI, Ali A, Hamid A, Shah SAA, Ashraf A. Spatiotemporal patterns of cutaneous leishmaniasis in the district upper and lower Dir, Khyber Pakhtunkhwa, Pakistan: A GIS-based spatial approaches. Acta Trop 2021; 217:105861. [PMID: 33587943 DOI: 10.1016/j.actatropica.2021.105861] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 02/02/2021] [Accepted: 02/08/2021] [Indexed: 12/24/2022]
Abstract
While Cutaneous leishmaniasis (CL) is not a life-threatening disease, it leads to devastating effects on local community. CL is widely scattered manifesting a noticeable epidemiological pattern around the globe. The present study was planned to address the role of Geographic Information System (GIS) using CL clinico-epidemiological data to determine the high-risk areas of CL. Recorded data (2014-2018) of 3630 positive individuals was collected from Basic Health Units of the Upper and Lower Dir Districts, Khyber Pakhtunkhwa, Pakistan. Descriptive and statistical analysis was used for clinico-epidemiological characterization. For spatial analysis, ArcGIS V.10.3 was used and the CL average incidence was tagged on the proportional, choropleth, and digital elevation model maps. For focal transmission and high-risk zones, Inverse Density Weight (IDW) spatial interpolation, focal statistics, hot spot, cluster and outlier, and Bayesian geostatistical analysis were used. The trend of CL cases was elevated from 2014 to 2016 except for 2017 and 2018. Individuals of both genders younger than 20 years old were highly susceptible. Single lesions were more prominent (56%) and frequently affected facial parts (51%). The size and pretreatment duration of the CL lesion was significantly associated. Spatially, a choropleth map displayed the maximum CL incidences in Tehsil Balambat, Khal, and Termergara (31%-13%) located within a range of 948-1947m elevation in the central regions with proximal CL transmissions. Hot spot and cluster and outlier analysis affirmed that Tehsil Khal was the high-risk CL foci. The Bayesian geostatistical analysis revealed high temperature, less altitude, and annual precipitation as important risk factors. An increasing trend in CL transmission has become evident, affecting both genders and <20 years old children. GIS resolute the concealed CL hubs in the least elevated central regions which warrant the control strategies to restrict future epidemics.
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11
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Toh KB, Bliznyuk N, Valle D. Improving national level spatial mapping of malaria through alternative spatial and spatio-temporal models. Spat Spatiotemporal Epidemiol 2021; 36:100394. [PMID: 33509423 DOI: 10.1016/j.sste.2020.100394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 11/28/2022]
Abstract
The most common approach to create spatial prediction of malaria in the literature is to approximate a Gaussian process model using stochastic partial differential equation (SPDE). We compared SPDE to computationally faster alternatives, generalized additive model (GAM) and state-of-the-art machine learning method gradient boosted trees (GBM), with respect to their predictive skill for country-level malaria prevalence mapping. We also evaluated the intuition that incorporation of past data and the use of spatio-temporal models may improve predictive accuracy of present spatial distribution of malaria. Model performances varied among the countries and setting with SPDE and GAM performed well generally. The inclusion of past data is beneficial for GAM and GBM, but not for SPDE. We further investigated the weaknesses of SPDE at spatio-temporal setting and GAM at the edges of the countries. Taken together, we believe that spatial/spatio-temporal SPDE models should be evaluated alongside with the alternatives or at least GAM.
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Affiliation(s)
- Kok Ben Toh
- School of Natural Resources and Environment, University of Florida, 103 Black Hall, Gainesville, Florida.
| | - Nikolay Bliznyuk
- Department of Agricultural and Biological Engineering, University of Florida, 1741 Museum Road, Gainesville, Florida
| | - Denis Valle
- School of Forest Resources and Conservation, University of Florida, 136 Newins-Ziegler Hall, Gainesville, Florida
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12
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Ajayakumar J, Curtis AJ, Rouzier V, Pape JW, Bempah S, Alam MT, Alam MM, Rashid MH, Ali A, Morris JG. Exploring convolutional neural networks and spatial video for on-the-ground mapping in informal settlements. Int J Health Geogr 2021; 20:5. [PMID: 33494756 PMCID: PMC7831241 DOI: 10.1186/s12942-021-00259-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 01/10/2021] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND The health burden in developing world informal settlements often coincides with a lack of spatial data that could be used to guide intervention strategies. Spatial video (SV) has proven to be a useful tool to collect environmental and social data at a granular scale, though the effort required to turn these spatially encoded video frames into maps limits sustainability and scalability. In this paper we explore the use of convolution neural networks (CNN) to solve this problem by automatically identifying disease related environmental risks in a series of SV collected from Haiti. Our objective is to determine the potential of machine learning in health risk mapping for these environments by assessing the challenges faced in adequately training the required classification models. RESULTS We show that SV can be a suitable source for automatically identifying and extracting health risk features using machine learning. While well-defined objects such as drains, buckets, tires and animals can be efficiently classified, more amorphous masses such as trash or standing water are difficult to classify. Our results further show that variations in the number of image frames selected, the image resolution, and combinations of these can be used to improve the overall model performance. CONCLUSION Machine learning in combination with spatial video can be used to automatically identify environmental risks associated with common health problems in informal settlements, though there are likely to be variations in the type of data needed for training based on location. Success based on the risk type being identified are also likely to vary geographically. However, we are confident in identifying a series of best practices for data collection, model training and performance in these settings. We also discuss the next step of testing these findings in other environments, and how adding in the simultaneously collected geographic data could be used to create an automatic health risk mapping tool.
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Affiliation(s)
- Jayakrishnan Ajayakumar
- Department of Population and Quantitative Health Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH USA
| | - Andrew J. Curtis
- Department of Population and Quantitative Health Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH USA
| | - Vanessa Rouzier
- Les Centres Haitian Group for the Study of Kaposi’s Sarcoma and Opportunistic Infections (GHESKIO), Port-au-Prince, Haiti
| | - Jean William Pape
- Les Centres Haitian Group for the Study of Kaposi’s Sarcoma and Opportunistic Infections (GHESKIO), Port-au-Prince, Haiti
| | - Sandra Bempah
- Department of Geography, Kent State University, Kent, OH USA
| | - Meer Taifur Alam
- Emerging Pathogens Institute and Department of Medicine, College of Medicine, University of Florida, Gainesville, FL 32601 USA
- Emerging Pathogens Institute and Department of Environmental & Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, FL 32601 USA
| | - Md. Mahbubul Alam
- Emerging Pathogens Institute and Department of Medicine, College of Medicine, University of Florida, Gainesville, FL 32601 USA
- Emerging Pathogens Institute and Department of Environmental & Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, FL 32601 USA
| | - Mohammed H. Rashid
- Emerging Pathogens Institute and Department of Medicine, College of Medicine, University of Florida, Gainesville, FL 32601 USA
| | - Afsar Ali
- Emerging Pathogens Institute and Department of Medicine, College of Medicine, University of Florida, Gainesville, FL 32601 USA
- Emerging Pathogens Institute and Department of Environmental & Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, FL 32601 USA
| | - John Glenn Morris
- Emerging Pathogens Institute and Department of Medicine, College of Medicine, University of Florida, Gainesville, FL 32601 USA
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Sharma RK, Rajvanshi H, Bharti PK, Nisar S, Jayswar H, Mishra AK, Saha KB, Shukla MM, Das A, Kaur H, Wattal SL, Lal AA. Socio-economic determinants of malaria in tribal dominated Mandla district enrolled in Malaria Elimination Demonstration Project in Madhya Pradesh. Malar J 2021; 20:7. [PMID: 33402186 PMCID: PMC7786971 DOI: 10.1186/s12936-020-03540-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 12/07/2020] [Indexed: 02/07/2023] Open
Abstract
Background Malaria is known as a disease of poverty because of its dominance in poverty-stricken areas. Madhya Pradesh state in central India is one of the most vulnerable states for malaria morbidity and mortality. Socio-economic, environmental and demographic factors present challenges in malaria control and elimination. As part of the Malaria Elimination Demonstration Project in the tribal district of Mandla in Madhya Pradesh, this study was undertaken to assess the role of different social-economic factors contributing to malaria incidence. Methods The study was conducted in the 1233 villages of district Mandla, where 87% population resides in rural areas. The data was collected using the android based mobile application—SOCH for a period of 2 years (September 2017 to August 2019). A wealth index was computed along with analysis of the socio-economic characteristics of houses with malaria cases. Variables with significant variation in malaria cases were used in logistic regression. Results More than 70% of houses in Mandla are Kuccha (made of thatched roof or mud), 20% do not have any toilet facilities, and only 11% had an annual income of more than 50,000 INR, which converts to about $700 per year. Households with younger heads, male heads, more number of family members were more likely to have malaria cases. Kuccha construction, improper water supply, low household income houses were also more likely to have a malaria case and the odds doubled in houses with no toilet facilities. Conclusion Based on the results of the study, it has been found that there is an association between the odds of having malaria cases and different household variables such as age, gender, number of members, number of rooms, caste, type of house, toilet facilities, water supply, cattle sheds, agricultural land, income, and vector control interventions. Therefore, a better understanding of the association of various risk factors that influence the incidence of malaria is required to design and/or deploy effective policies and strategies for malaria elimination. The results of this study suggest that appropriate economic and environmental interventions even in low-income and poverty-stricken tribal areas could have huge impact on the success of the national malaria elimination goals.
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Affiliation(s)
- Ravendra K Sharma
- Indian Council of Medical Research-National Institute of Research in Tribal Health, (ICMR-NIRTH), Jabalpur, Madhya Pradesh, India.
| | - Harsh Rajvanshi
- Malaria Elimination Demonstration Project, Mandla, Madhya Pradesh, India
| | - Praveen K Bharti
- Indian Council of Medical Research-National Institute of Research in Tribal Health, (ICMR-NIRTH), Jabalpur, Madhya Pradesh, India
| | - Sekh Nisar
- Malaria Elimination Demonstration Project, Mandla, Madhya Pradesh, India
| | - Himanshu Jayswar
- Directorate of Health Services, Government of Madhya Pradesh, Bhopal, India
| | - Ashok K Mishra
- Indian Council of Medical Research-National Institute of Research in Tribal Health, (ICMR-NIRTH), Jabalpur, Madhya Pradesh, India
| | - Kalyan B Saha
- Indian Council of Medical Research-National Institute of Research in Tribal Health, (ICMR-NIRTH), Jabalpur, Madhya Pradesh, India
| | - Man Mohan Shukla
- Indian Council of Medical Research-National Institute of Research in Tribal Health, (ICMR-NIRTH), Jabalpur, Madhya Pradesh, India
| | - Aparup Das
- Indian Council of Medical Research-National Institute of Research in Tribal Health, (ICMR-NIRTH), Jabalpur, Madhya Pradesh, India
| | - Harpreet Kaur
- Indian Council of Medical Research, Department of Health Research, Ministry of Health and Family Welfare, New Delhi, India
| | - Suman L Wattal
- National Vector Borne Disease Control Program, Ministry of Health and Family Welfare, New Delhi, India
| | - Altaf A Lal
- Malaria Elimination Demonstration Project, Mandla, Madhya Pradesh, India.,Foundation for Disease Elimination and Control of India, Mumbai, Maharashtra, India
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14
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Kiyonga Aimeé K, Lengu TB, Nsibu CN, Umesumbu SE, Ngoyi DM, Chen T. Molecular detection and species identification of Plasmodium spp. infection in adults in the Democratic Republic of Congo: A population-based study. PLoS One 2020; 15:e0242713. [PMID: 33227017 PMCID: PMC7682816 DOI: 10.1371/journal.pone.0242713] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 11/07/2020] [Indexed: 11/19/2022] Open
Abstract
Background In efforts to control malaria infection, the Democratic Republic of Congo has implemented several strategies. Studies assessing their efficiency mainly involved at-risk groups, especially children under five years of age. This study aimed to determine the prevalence and identify the risk factors associated with Plasmodium spp. infection. Methods From October 2014 to March 2015, individuals aged at least 15 years were selected randomly and enrolled in a cross-sectional study conducted throughout the country. Microscopy and polymerase chain reaction (PCR) analysis were used for the detection of Plasmodium ssp. Results From 2286 individuals recruited, 1870 with valid laboratory results were included in the study for further analysis. The prevalence of Plasmodium spp. infection assessed by microscopy (355/ 1870 (19%) was lower than that estimated by PCR (580/1870 (31%). In addition, the difference between the two results was statistically significant (P < 0.0001). The most prevalent Plasmodium species was P. falciparum, either as mono-infection (96.3%; 95% C.I. 93.9–98.1) or combined with P. malariae (3.7%; 95% C.I. 2.8–5.9). The mean parasite density was 3272739 trophozoites/μL of blood. Women had higher risks of being infected than men (OR 2.03, 95% C.I.: 1.96. 2.62, P = 0.041)]. Conclusion In this study, the molecular detection and species identification of Plasmodium spp. showed that, despite all efforts for malaria control, malaria remains a public health problem in the Democratic Republic of Congo. The high prevalence and parasite density of Plasmodium spp. in adults make this age group a potential parasitic infectious reservoir for the at-risk groups and supports the need to include this age group in further programs for malaria control.
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Affiliation(s)
- Kahindo Kiyonga Aimeé
- Department of Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences and Technology, Wuhan, People’s Republic of China
- Department of Tropical Medicine Infectious and Parasitic Diseases, University of Kinshasa, Kinshasa, Democratic Republic of Congo
- Institut National de Recherche Biomédicale (INRB), Kinshasa, Democratic Republic of Congo
- * E-mail:
| | - Thierry Bobanga Lengu
- Department of Tropical Medicine Infectious and Parasitic Diseases, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Célestin Ndosimao Nsibu
- Department of Pediatrics, University Hospital of Kinshasa, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
- Programme National de Lutte Contre le Paludisme (PNLP), Kinshasa, République Démocratique du Congo
| | - Solange Efundu Umesumbu
- Programme National de Lutte Contre le Paludisme (PNLP), Kinshasa, République Démocratique du Congo
| | - Dieudonné Mumba Ngoyi
- Department of Tropical Medicine Infectious and Parasitic Diseases, University of Kinshasa, Kinshasa, Democratic Republic of Congo
- Institut National de Recherche Biomédicale (INRB), Kinshasa, Democratic Republic of Congo
| | - Tie Chen
- Department of Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences and Technology, Wuhan, People’s Republic of China
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Loonen JACM, Dery DB, Musaka BZ, Bandibabone JB, Bousema T, van Lenthe M, Pop-Stefanija B, Fesselet JF, Koenraadt CJM. Identification of main malaria vectors and their insecticide resistance profile in internally displaced and indigenous communities in Eastern Democratic Republic of the Congo (DRC). Malar J 2020; 19:425. [PMID: 33228693 PMCID: PMC7684733 DOI: 10.1186/s12936-020-03497-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 11/15/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria remains a major public health concern in the Democratic Republic of the Congo (DRC) and its control is affected by recurrent conflicts. Médecins Sans Frontières (MSF) initiated several studies to better understand the unprecedented incidence of malaria to effectively target and implement interventions in emergency settings. The current study evaluated the main vector species involved in malaria transmission and their resistance to insecticides, with the aim to propose the most effective tools and strategies for control of local malaria vectors. METHODS This study was performed in 52 households in Shamwana (Katanga, 2014), 168 households in Baraka (South Kivu, 2015) and 269 households in Kashuga (North Kivu, 2017). Anopheles vectors were collected and subjected to standardized Word Health Organization (WHO) and Center for Disease Control (CDC) insecticide susceptibility bioassays. Mosquito species determination was done using PCR and Plasmodium falciparum infection in mosquitoes was assessed by ELISA targeting circumsporozoite protein. RESULTS Of 3517 Anopheles spp. mosquitoes collected, Anopheles gambiae sensu lato (s.l.) (29.6%) and Anopheles funestus (69.1%) were the main malaria vectors. Plasmodium falciparum infection rates for An. gambiae s.l. were 1.0, 2.1 and 13.9% for Shamwana, Baraka and Kashuga, respectively. Anopheles funestus showed positivity rates of 1.6% in Shamwana and 4.4% in Baraka. No An. funestus were collected in Kashuga. Insecticide susceptibility tests showed resistance development towards pyrethroids in all locations. Exposure to bendiocarb, malathion and pirimiphos-methyl still resulted in high mosquito mortality. CONCLUSIONS This is one of only few studies from these conflict areas in DRC to report insecticide resistance in local malaria vectors. The data suggest that current malaria prevention methods in these populations are only partially effective, and require additional tools and strategies. Importantly, the results triggered MSF to consider the selection of a new insecticide for indoor residual spraying (IRS) and a new long-lasting insecticide-treated net (LLIN). The reinforcement of correct usage of LLINs and the introduction of targeted larviciding were also included as additional vector control tools as a result of the studies.
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Affiliation(s)
| | - Dominic B Dery
- Médecins Sans Frontières (MSF), Amsterdam, The Netherlands
| | - Bertin Z Musaka
- Département de Biologie, Centre de Recherche en Sciences Naturelles (CRSN/Lwiro), Bukavu, South Kivu, Democratic Republic of the Congo
| | - Janvier B Bandibabone
- Département de Biologie, Centre de Recherche en Sciences Naturelles (CRSN/Lwiro), Bukavu, South Kivu, Democratic Republic of the Congo
| | - Teun Bousema
- Department of Medical Microbiology, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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Ciubotariu II, Jones CM, Kobayashi T, Bobanga T, Muleba M, Pringle JC, Stevenson JC, Carpi G, Norris DE. Genetic Diversity of Anopheles coustani (Diptera: Culicidae) in Malaria Transmission Foci in Southern and Central Africa. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:1782-1792. [PMID: 32614047 PMCID: PMC7899271 DOI: 10.1093/jme/tjaa132] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Indexed: 05/04/2023]
Abstract
Despite ongoing malaria control efforts implemented throughout sub-Saharan Africa, malaria remains an enormous public health concern. Current interventions such as indoor residual spraying with insecticides and use of insecticide-treated bed nets are aimed at targeting the key malaria vectors that are primarily endophagic and endophilic. Anopheles coustani s.l., an understudied vector of malaria, is a species previously thought to exhibit mostly zoophilic behavior. Like many of these understudied species, An. coustani has greater anthropophilic tendencies than previously appreciated, is often both endophagic and exophagic, and carries Plasmodium falciparum sporozoites. The aim of this study was to explore genetic variation of An. coustani mosquitoes and the potential of this species to contribute to malaria parasite transmission in high transmission settings in Zambia and the Democratic Republic of the Congo (DRC). Morphologically identified An. coustani specimens that were trapped outdoors in these study sites were analyzed by PCR and sequencing for species identification and bloodmeal sources, and malaria parasite infection was determined by ELISA and qPCR. Fifty An. coustani s.s. specimens were confirmed by analysis of mitochondrial DNA cytochrome c oxidase subunit I (COI) and ribosomal internal transcribed spacer region 2 (ITS2). Maximum likelihood phylogenetic analysis of COI and ITS2 sequences revealed two distinct phylogenetic groups within this relatively small regional collection. Our findings indicate that both An. coustani groups have anthropophilic and exophagic habits and come into frequent contact with P. falciparum, suggesting that this potential alternative malaria vector might elude current vector control measures in northern Zambia and southern DRC.
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Affiliation(s)
- Ilinca I Ciubotariu
- The Department of Biological Sciences, Purdue University, West Lafayette, IN
| | - Christine M Jones
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Tamaki Kobayashi
- The Department of Epidemiology, Division of Infectious Disease Epidemiology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Thierry Bobanga
- The Department of Family Medicine, School of Medicine, Université Protestante au Congo, Kinshasa, Democratic Republic of Congo
- The Department of Tropical Medicine, School of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | | | - Julia C Pringle
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Jennifer C Stevenson
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
- Macha Research Trust, Choma, Zambia
| | - Giovanna Carpi
- The Department of Biological Sciences, Purdue University, West Lafayette, IN
| | - Douglas E Norris
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
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Topazian HM, Gumbo A, Puerto-Meredith S, Njiko R, Mwanza A, Kayange M, Mwalilino D, Mvula B, Tegha G, Mvalo T, Edwards JK, Emch M, Pettifor A, Smith JS, Hoffman I, Meshnick SR, Juliano JJ. Asymptomatic Plasmodium falciparum malaria prevalence among adolescents and adults in Malawi, 2015-2016. Sci Rep 2020; 10:18740. [PMID: 33127922 PMCID: PMC7603306 DOI: 10.1038/s41598-020-75261-9] [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] [Received: 07/20/2020] [Accepted: 10/13/2020] [Indexed: 11/25/2022] Open
Abstract
Malaria remains a significant cause of morbidity and mortality in Malawi, with an estimated 18–19% prevalence of Plasmodium falciparum in children 2–10 years in 2015–2016. While children report the highest rates of clinical disease, adults are thought to be an important reservoir to sustained transmission due to persistent asymptomatic infection. The 2015–2016 Malawi Demographic and Health Survey was a nationally representative household survey which collected dried blood spots from 15,125 asymptomatic individuals ages 15–54 between October 2015 and February 2016. We performed quantitative polymerase chain reaction on 7,393 samples, detecting an overall P. falciparum prevalence of 31.1% (SE = 1.1). Most infections (55.6%) had parasitemias ≤ 10 parasites/µL. While 66.2% of individuals lived in a household that owned a bed net, only 36.6% reported sleeping under a long-lasting insecticide-treated net (LLIN) the previous night. Protective factors included urbanicity, greater wealth, higher education, and lower environmental temperatures. Living in a household with a bed net (prevalence difference 0.02, 95% CI − 0.02 to 0.05) and sleeping under an LLIN (0.01; − 0.02 to 0.04) were not protective against infection. Our findings demonstrate a higher parasite prevalence in adults than published estimates among children. Understanding the prevalence and distribution of asymptomatic infection is essential for targeted interventions.
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Affiliation(s)
- Hillary M Topazian
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, 27510, USA.
| | - Austin Gumbo
- National Malaria Control Programme, Malawi Ministry of Health, Lilongwe, Malawi
| | | | - Ruth Njiko
- University of North Carolina Project-Malawi, Lilongwe, Malawi
| | - Alexis Mwanza
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, 27510, USA
| | - Michael Kayange
- National Malaria Control Programme, Malawi Ministry of Health, Lilongwe, Malawi
| | - David Mwalilino
- National HIV Reference Laboratory, Malawi Ministry of Health, Lilongwe, Malawi
| | - Bernard Mvula
- National HIV Reference Laboratory, Malawi Ministry of Health, Lilongwe, Malawi
| | - Gerald Tegha
- University of North Carolina Project-Malawi, Lilongwe, Malawi
| | - Tisungane Mvalo
- University of North Carolina Project-Malawi, Lilongwe, Malawi.,Department of Pediatrics, School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Jessie K Edwards
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, 27510, USA
| | - Michael Emch
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, 27510, USA.,Department of Geography, University of North Carolina, Chapel Hill, NC, USA
| | - Audrey Pettifor
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, 27510, USA.,Carolina Population Center, University of North Carolina, Chapel Hill, NC, USA
| | - Jennifer S Smith
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, 27510, USA
| | - Irving Hoffman
- University of North Carolina Project-Malawi, Lilongwe, Malawi.,Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, NC, USA
| | - Steven R Meshnick
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, 27510, USA
| | - Jonathan J Juliano
- Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, NC, USA
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Bempah S, Curtis A, Awandare G, Ajayakumar J. Appreciating the complexity of localized malaria risk in Ghana: Spatial data challenges and solutions. Health Place 2020; 64:102382. [DOI: 10.1016/j.healthplace.2020.102382] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 06/20/2020] [Accepted: 06/25/2020] [Indexed: 02/06/2023]
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19
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Ipa M, Widawati M, Laksono AD, Kusrini I, Dhewantara PW. Variation of preventive practices and its association with malaria infection in eastern Indonesia: Findings from community-based survey. PLoS One 2020; 15:e0232909. [PMID: 32379812 PMCID: PMC7205284 DOI: 10.1371/journal.pone.0232909] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 04/23/2020] [Indexed: 12/23/2022] Open
Abstract
Background Geographical variation may likely influence the effectiveness of prevention efforts for malaria across Indonesia, in addition to factors at the individual level, household level, and contextual factors. This study aimed to describe preventive practices at individual and a household levels applied by rural communities in five provinces in eastern Indonesia and its association with the incidence of malaria among adult (≥15 years) populations. Methods This study analyzed a subset of data of nationally representative community-based survey 2018 Riset Kesehatan Dasar (Riskesdas). Data for socio-demographic (age, gender, education and occupation) and preventive behaviors (use of mosquito bed nets while slept, insecticide-treated mosquito nets (ITNs), mosquito repellent, mosquito electric rackets, mosquito coil/electric anti-mosquito mats, and mosquito window screen) were collected. Data were analyzed using bivariate and multivariable logistic regression model. Results Total of 56,159 respondents (n = 23,070 households) living in rural areas in Maluku (n = 8044), North Maluku (n = 7356), East Nusa Tenggara (n = 23,254), West Papua (n = 5759) and Papua (n = 11,746) were included in the study. In the multivariable models, using a bed net while slept likely reduced the odds of self-reported malaria among Maluku participants. Reduced odds ratios of self-reported malaria were identified in those participants who used ITNs (North Maluku, ENT, Papua), repellent (Maluku, West Papua, Papua), anti-mosquito racket (ENT), coil (Maluku, North Maluku, Papua) and window screen (West Papua, Papua). Conclusion Our study concluded that the protective effects of preventive practices were varied among localities, suggesting the need for specific intervention programs.
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Affiliation(s)
- Mara Ipa
- Pangandaran Unit for Health Research and Development, National Institute of Health Research and Development, National Ministry of Health of Indonesia, Pangandaran, West Java, Indonesia
- * E-mail:
| | - Mutiara Widawati
- Pangandaran Unit for Health Research and Development, National Institute of Health Research and Development, National Ministry of Health of Indonesia, Pangandaran, West Java, Indonesia
| | - Agung Dwi Laksono
- Center of Research and Development of Humanities and Health Management, National Institute of Health Research and Development, National Ministry of Health of Indonesia, Jakarta, Indonesia
| | - Ina Kusrini
- Magelang Unit for Health Research and Development, National Institute of Health Research and Development, National Ministry of Health of Indonesia, Magelang, Central Java, Indonesia
| | - Pandji Wibawa Dhewantara
- Pangandaran Unit for Health Research and Development, National Institute of Health Research and Development, National Ministry of Health of Indonesia, Pangandaran, West Java, Indonesia
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20
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Manda S, Haushona N, Bergquist R. A Scoping Review of Spatial Analysis Approaches Using Health Survey Data in Sub-Saharan Africa. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E3070. [PMID: 32354095 PMCID: PMC7246597 DOI: 10.3390/ijerph17093070] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/01/2020] [Accepted: 04/03/2020] [Indexed: 01/03/2023]
Abstract
Spatial analysis has become an increasingly used analytic approach to describe and analyze spatial characteristics of disease burden, but the depth and coverage of its usage for health surveys data in Sub-Saharan Africa are not well known. The objective of this scoping review was to conduct an evaluation of studies using spatial statistics approaches for national health survey data in the SSA region. An organized literature search for studies related to spatial statistics and national health surveys was conducted through PMC, PubMed/Medline, Scopus, NLM Catalog, and Science Direct electronic databases. Of the 4,193 unique articles identified, 153 were included in the final review. Spatial smoothing and prediction methods were predominant (n = 108), followed by spatial description aggregation (n = 25), and spatial autocorrelation and clustering (n = 19). Bayesian statistics methods and lattice data modelling were predominant (n = 108). Most studies focused on malaria and fever (n = 47) followed by health services coverage (n = 38). Only fifteen studies employed nonstandard spatial analyses (e.g., spatial model assessment, joint spatial modelling, accounting for survey design). We recommend that for future spatial analysis using health survey data in the SSA region, there must be an improve recognition and awareness of the potential dangers of a naïve application of spatial statistical methods. We also recommend a wide range of applications using big health data and the future of data science for health systems to monitor and evaluate impacts that are not well understood at local levels.
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Affiliation(s)
- Samuel Manda
- Biostatistics Research Unit, South African Medical Research Council, Pretoria 0001, South Africa
- Department of Statistics, University of Pretoria, Pretoria 0002, South Africa
- School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Pietermaritzburg 3209, South Africa
| | - Ndamonaonghenda Haushona
- Biostatistics Research Unit, South African Medical Research Council, Pretoria 0001, South Africa
- Division of Epidemiology and Biostatistics, University of Stellenbosch, Cape Town 8000, South Africa
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21
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Deress T, Girma M. Plasmodium falciparum and Plasmodium vivax Prevalence in Ethiopia: A Systematic Review and Meta-Analysis. Malar Res Treat 2019; 2019:7065064. [PMID: 32089818 PMCID: PMC7024085 DOI: 10.1155/2019/7065064] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 08/10/2019] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Malaria is a protozoan disease caused by the Plasmodium species. Among the five Plasmodium species. Among the five Plasmodium falciparum and Plasmodium vivax malaria are by far the most predominant and widely distributed in Ethiopia. Malaria is one of the leading causes of morbidity and mortality globally, particularly in the sub-Saharan countries including Ethiopia. It is also a major obstacle to socio-economic development in the country. METHODS Articles were searched from PubMed, Google Scholar, and Science Direct databases. The pooled prevalence estimates were analyzed using the DerSimonian-Laird random-effects model and the possible sources of heterogeneity were evaluated through subgroup analysis, metaregression, and sensitivity analysis. Publication bias was analyzed using funnel plots and Egger's test statistics. The data management and analysis were done using STATA 15.1 version software. RESULTS Among 922 studies initially identified, thirty-five full-text articles fulfilled the inclusion criteria and included in the study. The combined, Plasmodium falciparum and Plasmodium vivax malaria are by far the most predominant and widely. CONCLUSIONS This systematic review and meta-analysis showed a high malaria prevalence in Ethiopia. Therefore, previous prevention and control measures should be revised and/or strengthened as appropriate and new strategies should be implemented. In addition, technical, financial and material support, and coordination of the regional capacity building and logistics should be adequately implemented.
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Affiliation(s)
- Teshiwal Deress
- Unit of Quality Assurance and Laboratory Management, School of Biomedical and Laboratory Sciences, College of Medicine and Health Sciences, University of Gondar, P.O. Box 196, Gondar, Ethiopia
| | - Mekonnen Girma
- Unit of Quality Assurance and Laboratory Management, School of Biomedical and Laboratory Sciences, College of Medicine and Health Sciences, University of Gondar, P.O. Box 196, Gondar, Ethiopia
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22
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Janko M, Goel V, Emch M. Extending multilevel spatial models to include spatially varying coefficients. Health Place 2019; 60:102235. [PMID: 31778846 DOI: 10.1016/j.healthplace.2019.102235] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 10/04/2019] [Accepted: 10/08/2019] [Indexed: 11/27/2022]
Abstract
Multilevel models have long been used by health geographers working on questions of space, place, and health. Similarly, health geographers have pursued interests in determining whether or not the effect of an exposure on a health outcome varies spatially. However, relatively little work has sought to use multilevel models to explore spatial variability in the effects of a contextual exposure on a health outcome. Methodologically, extending multilevel models to allow intercepts and slopes to vary spatially is straightforward. The purpose of this paper, therefore, is to show how multilevel spatial models can be extended to include spatially varying covariate effects. We provide an empirical example on the effect of agriculture on malaria risk in children under 5 years of age in the Democratic Republic of Congo.
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Affiliation(s)
- Mark Janko
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA; Duke Global Health Institute, Duke University, Durham, NC, USA.
| | - Varun Goel
- Department of Geography, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA; Carolina Population Center, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA
| | - Michael Emch
- Department of Geography, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA; Carolina Population Center, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA; Department of Epidemiology, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA
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23
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Deutsch-Feldman M, Aydemir O, Carrel M, Brazeau NF, Bhatt S, Bailey JA, Kashamuka M, Tshefu AK, Taylor SM, Juliano JJ, Meshnick SR, Verity R. The changing landscape of Plasmodium falciparum drug resistance in the Democratic Republic of Congo. BMC Infect Dis 2019; 19:872. [PMID: 31640574 PMCID: PMC6805465 DOI: 10.1186/s12879-019-4523-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 09/30/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Drug resistant malaria is a growing concern in the Democratic Republic of the Congo (DRC), where previous studies indicate that parasites resistant to sulfadoxine/pyrimethamine or chloroquine are spatially clustered. This study explores longitudinal changes in spatial patterns to understand how resistant malaria may be spreading within the DRC, using samples from nation-wide population-representative surveys. METHODS We selected 552 children with PCR-detectable Plasmodium falciparum infection and identified known variants in the pfdhps and pfcrt genes associated with resistance. We compared the proportion of mutant parasites in 2013 to those previously reported from adults in 2007, and identified risk factors for carrying a resistant allele using multivariate mixed-effects modeling. Finally, we fit a spatial-temporal model to the observed data, providing smooth allele frequency estimates over space and time. RESULTS The proportion of co-occurring pfdhps K540E/A581G mutations increased by 16% between 2007 and 2013. The spatial-temporal model suggests that the spatial range of the pfdhps double mutants expanded over time, while the prevalence and range of pfcrt mutations remained steady. CONCLUSIONS This study uses population-representative samples to describe the changing landscape of SP resistance within the DRC, and the persistence of chloroquine resistance. Vigilant molecular surveillance is critical for controlling the spread of resistance.
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Affiliation(s)
- Molly Deutsch-Feldman
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, USA.
| | - Ozkan Aydemir
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA
| | - Margaret Carrel
- Department of Geographical & Sustainability Sciences, University of Iowa, Iowa City, IA, USA
| | - Nicholas F Brazeau
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, USA
| | - Samir Bhatt
- Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Jeffrey A Bailey
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA
| | - Melchior Kashamuka
- Ecole de Santé Publique, , Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Antoinette K Tshefu
- Ecole de Santé Publique, , Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Steve M Taylor
- Division of Infectious Diseases and Duke Global Health Institute, Duke University, Durham, NC, USA
| | - Jonathan J Juliano
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, USA.,Division of Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, USA.,Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, USA
| | - Robert Verity
- Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
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Kim S, Kim Y. Spatially Filtered Multilevel Analysis on Spatial Determinants for Malaria Occurrence in Korea. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16071250. [PMID: 30965608 PMCID: PMC6480462 DOI: 10.3390/ijerph16071250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/26/2019] [Accepted: 03/30/2019] [Indexed: 11/16/2022]
Abstract
Since its re-emergence in 1993, the spatial patterns of malaria outbreaks in South Korea have drastically changed. It is well known that complicated interactions between humans, nature, and socio-economic factors lead to a spatial dependency of vivax malaria occurrences. This study investigates the spatial factors determining malaria occurrences in order to understand and control malaria risks in Korea. A multilevel model is applied to simultaneously analyze the variables in different spatial scales, and eigenvector spatial filtering is used to explain the spatial autocorrelation in the malaria occurrence data. The results show that housing costs, average age, rice paddy field ratio, and distance from the demilitarized zone (DMZ) are significant on the level-1 spatial scale; health budget per capita and military base area ratio are significant on the level-2 spatial scale. The results show that the spatially filtered multilevel model provides better analysis results in handling spatial issues.
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Affiliation(s)
- Sehyeong Kim
- Department of Geography, Korea University, 145 Anam-ro, Seoul 02841, Korea.
| | - Youngho Kim
- Department of Geography Education, Korea University, 145 Anam-ro, Seoul 02841, Korea.
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25
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Dhewantara PW, Ipa M, Widawati M. Individual and contextual factors predicting self-reported malaria among adults in eastern Indonesia: findings from Indonesian community-based survey. Malar J 2019; 18:118. [PMID: 30947730 PMCID: PMC6449936 DOI: 10.1186/s12936-019-2758-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 03/30/2019] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Malaria is still an important parasitic infectious disease that affecting poor and vulnerable communities in many developing countries, including Indonesia. During the period of 2010-2017, there have been approximately 2.2 million confirmed malaria cases reported across Indonesia. This study aimed to identify individual, household and village-level factors associated with self-reported malaria among adults more than 15 years of age in Maluku, West Papua and Papua province. METHODS This study analysed a subset of the data from nationally representative population-based Indonesian National Basic Health Research (Riset Kesehatan Dasar) (N = 1,027,763 in 294,959 households in 33 provinces) in 2013. Total of 41,079 individuals (20,326 males and 20,753 females) aged ≥ 15 years in 19,269 households in Maluku, West Papua and Papua provinces were included. Participants were interviewed if they ever had been diagnosed and laboratory confirmed of having malaria by physician in the past 12 months. A mixed effects multilevel logistic regression models were developed to assess the associations between socio-demographical variables at individual, household and village level and self-reported malaria. RESULTS Individuals aged ≥ 15 years in 701 villages in Maluku (n = 11,919), West Papua (n = 8003) and Papua (n = 21,157) were analysed. In all provinces, gender distribution was equally-represented. The prevalence of self-reported malaria was 4.1% (Maluku), 12.4% (West Papua) and 18.8% (Papua). At the individual level, primary industry workers (OR 1.29, 95% CI 1.15-1.46 [Maluku]; OR 1.17, 95% CI 1.09-1.25 [Papua]) and having higher education were associated with self-reporting malaria (OR 0.67, 95% CI 0.53-0.83 [Maluku]; OR 1.27, 95% CI 1.15-1.40 [Papua]). Household level factors include having bed net and better off wealth index were associated with increased self-reporting malaria among West Papua (OR 1.21; 95% CI 1.09-1.34 and OR 1.38; 95% CI 1.17-1.65, respectively) and Papuan (OR 1.12; 95% CI 1.02-1.23 and OR 1.33; 95% CI 1.11-1.57, respectively) adults. Increased odds of self-reporting malaria was associated with time required to reach healthcare facility (OR 1.30, 95% CI 1.01-1.67 [Maluku]). Contextual village-level characteristics such as living in rural (OR 1.31, 95% CI 1.12-1.54 [Maluku]; OR 1.56, 95% CI 1.17-2.07 [West Papua]), higher community education level (OR 1.28, 95% CI 1.02-1.63 [West Papua]; OR 1.45, 95% CI 1.23-1.72 [Papua]), higher community bed net ownerships (OR 0.59 95% CI 0.45-0.77 [West Papua]) were associated with self-reported malaria. CONCLUSIONS Factors associated with self-reported malaria were varied between provinces suggesting locally-specific determinants were exist at individual, household and community-level. This study highlights the need for specific interventions by taking into consideration the contextual factors within the region and involving multi-sectoral collaboration between health authorities and related stakeholders (e.g., bureau of education, bureau of public works and infrastructure) to improve designs in planning and intervention strategies to succesfully eliminate malaria in Maluku and Papua.
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Affiliation(s)
- Pandji Wibawa Dhewantara
- Pangandaran Unit for Health Research and Development, National Institute of Health Research and Development, Ministry of Health of Indonesia, Pangandaran, West Java, 46396, Indonesia. .,School of Veterinary Science, University of Queensland, Gatton, QLD, 4343, Australia.
| | - Mara Ipa
- Pangandaran Unit for Health Research and Development, National Institute of Health Research and Development, Ministry of Health of Indonesia, Pangandaran, West Java, 46396, Indonesia
| | - Mutiara Widawati
- Pangandaran Unit for Health Research and Development, National Institute of Health Research and Development, Ministry of Health of Indonesia, Pangandaran, West Java, 46396, Indonesia
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Hasyim H, Dhimal M, Bauer J, Montag D, Groneberg DA, Kuch U, Müller R. Does livestock protect from malaria or facilitate malaria prevalence? A cross-sectional study in endemic rural areas of Indonesia. Malar J 2018; 17:302. [PMID: 30126462 PMCID: PMC6102806 DOI: 10.1186/s12936-018-2447-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 08/05/2018] [Indexed: 11/20/2022] Open
Abstract
Background Ever since it was discovered that zoophilic vectors can transmit malaria, zooprophylaxis has been used to prevent the disease. However, zoopotentiation has also been observed. Thus, the presence of livestock has been widely accepted as an important variable for the prevalence and risk of malaria, but the effectiveness of zooprophylaxis remained subject to debate. This study aims to critically analyse the effects of the presence of livestock on malaria prevalence using a large dataset from Indonesia. Methods This study is based on data from the Indonesia Basic Health Research (“Riskesdas”) cross-sectional survey of 2007 organized by the National Institute of Health Research and Development of Indonesia’s Ministry of Health. The subset of data used in the present study included 259,885 research participants who reside in the rural areas of 176 regencies throughout the 15 provinces of Indonesia where the prevalence of malaria is higher than the national average. The variable “existence of livestock” and other independent demographic, social and behavioural variables were tested as potential determinants for malaria prevalence by multivariate logistic regressions. Results Raising medium-sized animals in the house was a significant predictor of malaria prevalence (OR = 2.980; 95% CI 2.348–3.782, P < 0.001) when compared to keeping such animals outside of the house (OR = 1.713; 95% CI 1.515–1.937, P < 0.001). After adjusting for gender, age, access to community health facility, sewage canal condition, use of mosquito nets and insecticide-treated bed nets, the participants who raised medium-sized animals inside their homes were 2.8 times more likely to contract malaria than respondents who did not (adjusted odds ratio = 2.809; 95% CI 2.207–3.575; P < 0.001). Conclusions The results of this study highlight the importance of livestock for malaria transmission, suggesting that keeping livestock in the house contributes to malaria risk rather than prophylaxis in Indonesia. Livestock-based interventions should therefore play a significant role in the implementation of malaria control programmes, and focus on households with a high proportion of medium-sized animals in rural areas. The implementation of a “One Health” strategy to eliminate malaria in Indonesia by 2030 is strongly recommended. Electronic supplementary material The online version of this article (10.1186/s12936-018-2447-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hamzah Hasyim
- Faculty of Medicine, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany. .,Faculty of Public Health, Sriwijaya University, Indralaya, South Sumatra, Indonesia.
| | - Meghnath Dhimal
- Faculty of Medicine, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany.,Nepal Health Research Council, Ramshah Path, Kathmandu, Nepal
| | - Jan Bauer
- Faculty of Medicine, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Doreen Montag
- Centre for Primary Care and Public Health, Barts and the London School of Medicine, Queen Mary University of London, London, UK
| | - David A Groneberg
- Faculty of Medicine, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Ulrich Kuch
- Faculty of Medicine, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Ruth Müller
- Faculty of Medicine, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
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Spatial modelling of malaria cases associated with environmental factors in South Sumatra, Indonesia. Malar J 2018; 17:87. [PMID: 29463239 PMCID: PMC5819714 DOI: 10.1186/s12936-018-2230-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 02/13/2018] [Indexed: 11/12/2022] Open
Abstract
Background Malaria, a parasitic infection, is a life-threatening disease in South Sumatra Province, Indonesia. This study aimed to investigate the spatial association between malaria occurrence and environmental risk factors. Methods The number of confirmed malaria cases was analysed for the year 2013 from the routine reporting of the Provincial Health Office of South Sumatra. The cases were spread over 436 out of 1613 villages. Six potential ecological predictors of malaria cases were analysed in the different regions using ordinary least square (OLS) and geographically weighted regression (GWR). The global pattern and spatial variability of associations between malaria cases and the selected potential ecological predictors was explored. Results The importance of different environmental and geographic parameters for malaria was shown at global and village-level in South Sumatra, Indonesia. The independent variables altitude, distance from forest, and rainfall in global OLS were significantly associated with malaria cases. However, as shown by GWR model and in line with recent reviews, the relationship between malaria and environmental factors in South Sumatra strongly varied spatially in different regions. Conclusions A more in-depth understanding of local ecological factors influencing malaria disease as shown in present study may not only be useful for developing sustainable regional malaria control programmes, but can also benefit malaria elimination efforts at village level.
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Janko MM, Irish SR, Reich BJ, Peterson M, Doctor SM, Mwandagalirwa MK, Likwela JL, Tshefu AK, Meshnick SR, Emch ME. The links between agriculture, Anopheles mosquitoes, and malaria risk in children younger than 5 years in the Democratic Republic of the Congo: a population-based, cross-sectional, spatial study. Lancet Planet Health 2018; 2:e74-e82. [PMID: 29457150 PMCID: PMC5809714 DOI: 10.1016/s2542-5196(18)30009-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
BACKGROUND The relationship between agriculture, Anopheles mosquitoes, and malaria in Africa is not fully understood, but it is important for malaria control as countries consider expanding agricultural projects to address population growth and food demand. Therefore, we aimed to assess the effect of agriculture on Anopheles biting behaviour and malaria risk in children in rural areas of the Democratic Republic of the Congo (DR Congo). METHODS We did a population-based, cross-sectional, spatial study of rural children (<5 years) in the DR Congo. We used information about the presence of malaria parasites in each child, as determined by PCR analysis of dried-blood spots from the 2013-14 DR Congo Demographic and Health Survey (DHS). We also used data from the DHS, a longitudinal entomological study, and available land cover and climate data to evaluate the relationships between agriculture, Anopheles biting behaviour, and malaria prevalence. Satellite imagery was used to measure the percentage of agricultural land cover around DHS villages and Anopheles sites. Anopheles biting behaviour was assessed by Human Landing Catch. We used probit regression to assess the relationship between agriculture and the probability of malaria infection, as well as the relationship between agriculture and the probability that a mosquito was caught biting indoors. FINDINGS Between Aug 13, 2013, and Feb 13, 2014, a total of 9790 dried-blood spots were obtained from the DHS, of which 4612 participants were included in this study. Falciparum malaria infection prevalence in rural children was 38·7% (95% uncertainty interval [UI] 37·3-40·0). Increasing exposure to agriculture was associated with increasing malaria risk with a high posterior probability (estimate 0·07, 95% UI -0·04 to 0·17; posterior probability [estimate >0]=0·89), with the probability of malaria infection increased between 0·2% (95% UI -0·1 to 3·4) and 2·6% (-1·5 to 6·6) given a 15% increase in agricultural cover, depending on other risk factors. The models predicted that large increases in agricultural cover (from 0% to 75%) increase the probability of infection by as much as 13·1% (95% UI -7·3 to 28·9). Increased risk might be due to Anopheles gambiae sensu lato, whose probability of biting indoors increased between 11·3% (95% UI -15·3 to 25·6) and 19·7% (-12·1 to 35·9) with a 15% increase in agriculture. INTERPRETATION Malaria control programmes must consider the possibility of increased risk due to expanding agriculture. Governments considering initiating large-scale agricultural projects should therefore also consider accompanying additional malaria control measures. FUNDING National Institutes of Health, National Science Foundation, Bill & Melinda Gates Foundation, President's Malaria Initiative, and Royster Society of Fellows at the University of North Carolina at Chapel Hill.
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Affiliation(s)
- Mark M Janko
- Duke Global Health Institute, Duke University, Durham, NC, USA; Department of Geography, Chapel Hill, NC, USA; Department of Biostatistics, Chapel Hill, NC, USA; Carolina Population Center, Chapel Hill, NC, USA.
| | - Seth R Irish
- University of North Carolina, Chapel Hill, NC, USA; President's Malaria Initiative and Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Brian J Reich
- Department of Statistics, North Carolina State University, Raleigh, NC, USA
| | | | | | | | - Joris L Likwela
- Programme National de Lutte contre le Paludisme, Kinshasa, Democratic Republic of the Congo
| | - Antoinette K Tshefu
- Department of Community Health, Ecole de Santé Publique, Faculté de Médecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | | | - Michael E Emch
- Department of Geography, Chapel Hill, NC, USA; Carolina Population Center, Chapel Hill, NC, USA; Department of Epidemiology, Chapel Hill, NC, USA
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Levitz L, Janko M, Mwandagalirwa K, Thwai KL, Likwela JL, Tshefu AK, Emch M, Meshnick SR. Effect of individual and community-level bed net usage on malaria prevalence among under-fives in the Democratic Republic of Congo. Malar J 2018; 17:39. [PMID: 29347953 PMCID: PMC5774036 DOI: 10.1186/s12936-018-2183-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 01/10/2018] [Indexed: 11/10/2022] Open
Abstract
Background Understanding the contribution of community-level long-lasting, insecticidal net (LLIN) coverage to malaria control is critical to planning and assessing intervention campaigns. The Democratic Republic of Congo (DRC), which has one of the highest burdens of malaria cases and deaths and has dramatically scaled up LLIN ownership in recent years thus it is an ideal setting to evaluate the effect of individual versus community-level use to prevent malaria among children under the age of 5. Results Data were derived from the 2013–2014 DRC Demographic and Health Survey. Community-level LLIN usage was significantly associated with protection against malaria, even when individual-level LLIN usage was included in the model. In stratified analysis, higher levels of community LLIN coverage enhanced the protective effect of individual LLIN usage, resulting in lower malaria prevalence among individuals who used a LLIN. A sub-analysis of individual LLIN usage by insecticide type revealed deltamethrin-treated nets were more protective than permethrin-treated nets, suggesting that mosquitoes in the DRC are more susceptible to deltamethrin. Conclusions This study examines the effects of individual and community-level LLIN usage in young children in an area of high ITN usage. Individual and community LLIN usage were significantly associated with protection against malaria in children under 5 in the DRC. Importantly, the protective effect of individual LLIN usage against malaria is enhanced when community LLIN coverage is higher, demonstrating the importance of increasing community-level LLIN usage. LLINs treated with deltamethrin were shown to be more protective against malaria than LLINs treated with permethrin. Demographic and Health Surveys are thus a novel and important means of surveillance for insecticide resistance.
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Affiliation(s)
- Lauren Levitz
- Department of Epidemiology, University of North Carolina, Gillings School of Global Public Health, 135 Dauer Drive, 3113 Michael Hooker Research Building, Chapel Hill, NC, 27599, USA
| | - Mark Janko
- Department of Geography, University of North Carolina Gillings School of Global Public Health, Chapel Hill, NC, 27599, USA
| | | | - Kyaw L Thwai
- Department of Epidemiology, University of North Carolina, Gillings School of Global Public Health, 135 Dauer Drive, 3113 Michael Hooker Research Building, Chapel Hill, NC, 27599, USA
| | - Joris L Likwela
- Programme National de la Lutte contre le Paludisme, Kinshasa, Democratic Republic of Congo
| | - Antoinette K Tshefu
- University of Kinshasa School of Public Health, Kinshasa, Democratic Republic of Congo
| | - Michael Emch
- Department of Geography, University of North Carolina Gillings School of Global Public Health, Chapel Hill, NC, 27599, USA
| | - Steven R Meshnick
- Department of Epidemiology, University of North Carolina, Gillings School of Global Public Health, 135 Dauer Drive, 3113 Michael Hooker Research Building, Chapel Hill, NC, 27599, USA.
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Stebbins RC, Emch M, Meshnick SR. The Effectiveness of Community Bed Net Use on Malaria Parasitemia among Children Less Than 5 Years Old in Liberia. Am J Trop Med Hyg 2018; 98:660-666. [PMID: 29363457 DOI: 10.4269/ajtmh.17-0619] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In 2013, the under-5 mortality rate in Liberia was 71 deaths per 1,000 live births, with malaria responsible for 22% of those deaths. One of the primary existing control tools, long-lasting insecticide-treated bed nets (LLINs), is thought to be dually effective, acting as a physical barrier but also decreasing the mosquito population in communities. However, there has been little investigation into the protective effects of community-wide bed net use above and beyond the individual level. Using data from the population-representative 2011 Liberia Malaria Indicator Survey, we estimated the association between proportion of a community using LLINs and malaria in children using multi-level logistic regression. To investigate the potential effect measure modification of the relationship by urbanicity, we included an interaction term and calculated stratum-specific prevalence odds ratios (PORs) for rural and urban communities. We calculated a POR of malaria for an absolute 10% increase in community bed net use of 1.13 (95% confidence interval [CI]: 0.91, 1.41) and 0.35 (95% CI: 0.13, 0.92) for rural and urban communities, respectively, indicating a strong, though imprecise, protective effect within urban communities only. Our results indicate that bed net use has an indirect protective effect in urban areas, above and beyond individual use. Little or no such effect of community-wide use is seen in rural areas, likely because of population density factors. Therefore, although all control efforts should be multifaceted, promotion of bed net use in urban areas in particular will likely be a highly effective tool for control.
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Affiliation(s)
- Rebecca C Stebbins
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Michael Emch
- Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Miller RH, Hathaway NJ, Kharabora O, Mwandagalirwa K, Tshefu A, Meshnick SR, Taylor SM, Juliano JJ, Stewart VA, Bailey JA. A deep sequencing approach to estimate Plasmodium falciparum complexity of infection (COI) and explore apical membrane antigen 1 diversity. Malar J 2017; 16:490. [PMID: 29246158 PMCID: PMC5732508 DOI: 10.1186/s12936-017-2137-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 12/06/2017] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Humans living in regions with high falciparum malaria transmission intensity harbour multi-strain infections comprised of several genetically distinct malaria haplotypes. The number of distinct malaria parasite haplotypes identified from an infected human host at a given time is referred to as the complexity of infection (COI). In this study, an amplicon-based deep sequencing method targeting the Plasmodium falciparum apical membrane antigen 1 (pfama1) was utilized to (1) investigate the relationship between P. falciparum prevalence and COI, (2) to explore the population genetic structure of P. falciparum parasites from malaria asymptomatic individuals participating in the 2007 Demographic and Health Survey (DHS) in the Democratic Republic of Congo (DRC), and (3) to explore selection pressures on geospatially divergent parasite populations by comparing AMA1 amino acid frequencies in the DRC and Mali. RESULTS A total of 900 P. falciparum infections across 11 DRC provinces were examined. Deep sequencing of both individuals, for COI analysis, and pools of individuals, to examine population structure, identified 77 unique pfama1 haplotypes. The majority of individual infections (64.5%) contained polyclonal (COI > 1) malaria infections based on the presence of genetically distinct pfama1 haplotypes. A minimal correlation between COI and malaria prevalence as determined by sensitive real-time PCR was identified. Population genetic analyses revealed extensive haplotype diversity, the vast majority of which was shared across the sites. AMA1 amino acid frequencies were similar between parasite populations in the DRC and Mali. CONCLUSIONS Amplicon-based deep sequencing is a useful tool for the detection of multi-strain infections that can aid in the understanding of antigen heterogeneity of potential malaria vaccine candidates, population genetics of malaria parasites, and factors that influence complex, polyclonal malaria infections. While AMA1 and other diverse markers under balancing selection may perform well for understanding COI, they may offer little geographic or temporal discrimination between parasite populations.
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Affiliation(s)
- Robin H Miller
- Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD, USA
| | - Nicholas J Hathaway
- Program in Bioinformatics and Integrative Biology, University of Massachusetts School of Medicine, 55 Lake Avenue North, Worcester, MA, USA
| | - Oksana Kharabora
- University of North Carolina School of Medicine, 101 Manning Drive, Chapel Hill, NC, USA
| | - Kashamuka Mwandagalirwa
- Ecole de Santé Publique, Université de Kinshasa, Commune de Lemba, P.O Box 11850, Kinshasa, Democratic Republic of Congo
| | - Antoinette Tshefu
- Ecole de Santé Publique, Université de Kinshasa, Commune de Lemba, P.O Box 11850, Kinshasa, Democratic Republic of Congo
| | - Steven R Meshnick
- University of North Carolina School of Medicine, 101 Manning Drive, Chapel Hill, NC, USA
| | - Steve M Taylor
- Division of Infectious Diseases and Duke Global Health Institute, Duke University Medical Center, 303 Research Drive, Durham, NC, USA
| | - Jonathan J Juliano
- University of North Carolina School of Medicine, 101 Manning Drive, Chapel Hill, NC, USA
| | - V Ann Stewart
- Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD, USA
| | - Jeffrey A Bailey
- Program in Bioinformatics and Integrative Biology, University of Massachusetts School of Medicine, 55 Lake Avenue North, Worcester, MA, USA.
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Individual and household characteristics of persons with Plasmodium falciparum malaria in sites with varying endemicities in Kinshasa Province, Democratic Republic of the Congo. Malar J 2017; 16:456. [PMID: 29121931 PMCID: PMC5680818 DOI: 10.1186/s12936-017-2110-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 11/06/2017] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The Democratic Republic of the Congo (DRC) bears a large share of global malaria burden despite efforts to control and eliminate the disease. More detailed understanding of individual and household level characteristics associated with malaria are needed, as is an understanding of how these characteristics vary spatiotemporally and across different community-level malaria endemicities. An ongoing study in Kinshasa Province is designed to address gaps in prior malaria surveillance in the DRC by monitoring malaria across seasons, age groups and in high and low malaria sites. Across seven sites, 242 households and 1591 individuals are participating in the study. Results of the enrollment questionnaire, rapid diagnostic tests and PCR testing of dried blood spots are presented. RESULTS Overall malaria prevalence in the study cohort is high, 27% by rapid diagnostic test and 31% by polymerase chain reaction, and malaria prevalence is highly varied across very small geographic distances. Malaria prevalence is highest in children aged 6-15. While the majority of households own bed nets, bed net usage is less than 50%. CONCLUSIONS The study cohort will provide an understanding of how malaria persists in populations that have varying environmental exposures, varying community-level malaria, and varying access to malaria control efforts.
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Mfueni Bikundi E, Coppieters Y. Importance of risk factors associated with malaria for Sub-Saharan African children. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2017; 27:394-408. [PMID: 28786293 DOI: 10.1080/09603123.2017.1359241] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 07/16/2017] [Indexed: 06/07/2023]
Abstract
To assess the importance of malaria risk factors for children in sub-Saharan African countries. 61,292 children of 16 countries from DHS and MIS surveys were included in analysis. A regression model with analyse of variance and plots of mean decrease accuracy and mean decrease Gini indices were performed. The most important risk factor was the country and it contributed 52.33 % to the variance of the model. Wealth status of the child's family was the first socio-economic factor which contributed more to the difference of malaria risk among African children. There was no geographic factor among the five most important variables. Quantity of precipitation was the sixth most important factor. Our study has the potential for driving control effort in the fight against malaria in the continent which represent the majority of global malaria cases. The study indicates that, when implementing health policies, community characteristics must be taken into account.
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Affiliation(s)
- Elvire Mfueni Bikundi
- a Epidemiology, Biostatistics and Clinical Research Center, School of Public Health , Université Libre de Bruxelles (ULB) , Brussels , Belgium
| | - Yves Coppieters
- a Epidemiology, Biostatistics and Clinical Research Center, School of Public Health , Université Libre de Bruxelles (ULB) , Brussels , Belgium
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Ajayi IO, Nsungwa-Sabiiti J, Siribié M, Petzold M, Castellani J, Singlovic J, Gomes M. Reply to Brooks et al. Clin Infect Dis 2017; 65:530-531. [PMID: 28838135 DOI: 10.1093/cid/cix383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- IkeOluwapo O Ajayi
- Department of Epidemiology and Medical Statistics, Institute of Advanced Medical Research and Training, College of Medicine, University of Ibadan, Nigeria
| | | | | | - Max Petzold
- Department of Health Services Research, School for Public Health and Primary Care, Maastricht University, The Netherlands
| | - Joëlle Castellani
- Centre for Applied Biostatistics, Occupational and Environmental Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - Jan Singlovic
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Melba Gomes
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland
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Komen K. Could Malaria Control Programmes be Timed to Coincide with Onset of Rainfall? ECOHEALTH 2017; 14:259-271. [PMID: 28378182 DOI: 10.1007/s10393-017-1230-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 11/27/2016] [Accepted: 02/27/2017] [Indexed: 06/07/2023]
Abstract
Malaria cases in South Africa's Northern Province of Limpopo have surpassed known endemic KwaZulu Natal and Mpumalanga Provinces. This paper applies statistical methods: regression analysis and impulse response function to understand the timing of impact and the length that such impacts last. Climate data (rainfall and temperature) are obtained from South African Weather Services (SAWs); global data from the European Centre for Medium-Range Weather Forecasts (ECMWF), while clinical malaria data came from Malaria Control Centre in Tzaneen (Limpopo Province). Data collected span from January 1998 to July 2007. Signs of the coefficients are positive for rainfall and temperature and negative for their exponents. Three out of five independent variables consistently maintain a very high statistical level of significance. The coefficients for climate variables describe an inverted u-shape: parameters for the exponents of rainfall (-0.02, -0.01, -0.02, -0.00) and temperature (-46.61, -47.46, -48.14, -36.04) are both negative. A one standard deviation rise in rainfall (rainfall onset) increases malaria cases, and the effects become sustained for at least 3 months and conclude that onset of rainfall therefore triggers a 'malaria season'. Malaria control programme and early warning system should be intensified in the first 3 months following the onset of rainfall.
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Affiliation(s)
- Kibii Komen
- , City of Tshwane, City Sustainability Unit, Office of the Executive Mayor, P.O. Box 440, Pretoria, 0001, South Africa.
- Department of geography, Geoinformatics and Meteorology, Center for Environmental Studies, University of Pretoria, Pretoria, 0002, South Africa.
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Sumbele IUN, Nkemnji GB, Kimbi HK. Soil-transmitted helminths and plasmodium falciparum malaria among individuals living in different agroecosystems in two rural communities in the mount Cameroon area: a cross-sectional study. Infect Dis Poverty 2017; 6:67. [PMID: 28302147 PMCID: PMC5353792 DOI: 10.1186/s40249-017-0266-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 02/17/2017] [Indexed: 11/30/2022] Open
Abstract
Background Soil-transmitted helminths (STHs) and Plasmodium falciparum infections remain public health problems in Cameroon. A cross-sectional study was carried out in the Mount Cameroon area to determine the prevalence and intensity of STHs and P. falciparum infections in individuals living in different agroecosystems; to assess the influence of these infections on haematological parameters; and to identify the risk factors associated with STH infections. Methods STH and malaria parasites were detected using the Kato-Katz method and Giemsa staining of blood films, respectively. Complete blood count values were obtained using an automatic haematology analyser. Soil samples were analysed using the sucrose floatation sedimentation method. Categorical and continuous variables were compared as required and logistic regression models were used to assess the risk factors for STH infections and anaemia. Results Of the 450 participants examined, STHs, P. falciparum and mixed co-infections were detected in 14.0, 33.3 and 5.6% of participants, respectively. Significantly higher prevalences of Ascaris (18.8%) and Trichuris (7.9%) infections were observed in participants from tea plantation areas compared to those from banana and palm plantation areas, with similar trends in egg density. P. falciparum prevalence and parasite density were comparable between the different agroecosystems. The overall prevalence of anaemia was 64.2%. The prevalence of haematological manifestations such as moderate (48.0%) and severe (8.0%) anaemia, leucopenia (26.9%) and microcytosis (30.8%) was significantly higher among Plasmodium-STH co-infected participants. Soil samples from plantations showed the highest prevalences of STH eggs compared to soil samples from areas around pit toilets and public water taps. Living in a tea plantation area (OR = 3.07), age (AOR = 1.49) and lack of access to potable water (OR = 2.25) were identified as risk factors for STH infections, while the age groups 15–25 years (OR = 2.928) and 26–35 years (OR = 2.832), and being female (OR = 2.671) were significant risk factors for anaemia. Conclusions STHs, malaria and anaemia are still of public health concern in plantation communities. Co-infections negatively influence haematological parameters. The tea farming agroecosystem, age and lack of access to potable water were identified as significant risk factors for STH infections. Trial registration Not applicable. Electronic supplementary material The online version of this article (doi:10.1186/s40249-017-0266-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | - Helen Kuokuo Kimbi
- Department of Zoology and Animal Physiology, University of Buea, Buea, Cameroon.,Department of Medical Laboratory Sciences, University of Bamenda, Bamenda, Cameroon
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Charchuk R, Paul MKJ, Claude KM, Houston S, Hawkes MT. Burden of malaria is higher among children in an internal displacement camp compared to a neighbouring village in the Democratic Republic of the Congo. Malar J 2016; 15:431. [PMID: 27557931 PMCID: PMC4997722 DOI: 10.1186/s12936-016-1479-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 08/10/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In the Democratic Republic of the Congo (DRC), violent conflict has caused the displacement of millions of people into camps where they are exposed to poor living conditions and high rates of infectious diseases. Malaria, in particular, is a major cause of mortality in children under five; however, the burden of disease in displacement camps has not previously been described. METHODS Two cross-sectional surveys were performed. First, prevalence of Plasmodium falciparum antigenemia was measured in a random sample of 200 children living in a displacement camp and 200 children from a nearby village (control group). Second, the proportion of febrile illness attributable to malaria was measured in a study of 100 children from the displacement camp and 100 children from the control village presenting to the same health clinic with fever. All participants were tested for P. falciparum with a rapid diagnostic test and additional demographic data, clinical characteristics, and malaria risk factors were determined using a parental questionnaire. RESULTS In the community survey, children living in the displacement camp had a higher prevalence of P. falciparum infection (17 %) than controls (7.5 %) (OR 2.6; 95 % CI 1.3-4.1; P = 0.0095). In the clinic-based survey, the proportion of febrile illness attributable to malaria was higher among children from the displacement camp (78 %) than controls (39 %) (OR 5.5; 95 % CI 3.0-10.3; P < 0.001). Household bed net ownership and use was significantly lower in the displacement camp than control village in both surveys. Statistically significant differences in household wealth, maternal education, and exposure to community violence were also found. CONCLUSIONS Population displacement due to violent conflict appears to be a risk factor for malaria, a major cause of child mortality. Children living in displacement camps are a relatively understudied population, but have a high burden of malaria, despite control programmes focused on bed net distribution.
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Affiliation(s)
- Rhianna Charchuk
- School of Public Health, University of Alberta, Edmonton, Canada
| | | | | | - Stan Houston
- School of Public Health, University of Alberta, Edmonton, Canada.,Department of Medicine, University of Alberta, Edmonton, Canada
| | - Michael T Hawkes
- School of Public Health, University of Alberta, Edmonton, Canada. .,Department of Pediatrics, University of Alberta, Edmonton, Canada.
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Sedda L, Qi Q, Tatem AJ. A geostatistical analysis of the association between armed conflicts and Plasmodium falciparum malaria in Africa, 1997-2010. Malar J 2015; 14:500. [PMID: 26670739 PMCID: PMC4681145 DOI: 10.1186/s12936-015-1024-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 11/27/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The absence of conflict in a country has been cited as a crucial factor affecting the operational feasibility of achieving malaria control and elimination, yet mixed evidence exists on the influence that conflicts have had on malaria transmission. Over the past two decades, Africa has seen substantial numbers of armed conflicts of varying length and scale, creating conditions that can disrupt control efforts and impact malaria transmission. However, very few studies have quantitatively assessed the associations between conflicts and malaria transmission, particularly in a consistent way across multiple countries. METHODS In this analysis an explicit geostatistical, autoregressive, mixed model is employed to quantitatively assess the association between conflicts and variations in Plasmodium falciparum parasite prevalence across a 13-year period in sub-Saharan Africa. RESULTS Analyses of geolocated, malaria prevalence survey variations against armed conflict data in general showed a wide, but short-lived impact of conflict events geographically. The number of countries with decreased P. falciparum parasite prevalence (17) is larger than the number of countries with increased transmission (12), and notably, some of the countries with the highest transmission pre-conflict were still found with lower transmission post-conflict. For four countries, there were no significant changes in parasite prevalence. Finally, distance from conflicts, duration of conflicts, violence of conflict, and number of conflicts were significant components in the model explaining the changes in P. falciparum parasite rate. CONCLUSIONS The results suggest that the maintenance of intervention coverage and provision of healthcare in conflict situations to protect vulnerable populations can maintain gains in even the most difficult of circumstances, and that conflict does not represent a substantial barrier to elimination goals.
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Affiliation(s)
- Luigi Sedda
- CHICAS, Lancaster Medical School, Lancaster University, Furness Building, Lancaster, LA1 4YG, UK.
| | - Qiuyin Qi
- Department of Geography, University of Florida, Gainesville, FL, 32611-7315, USA.
| | - Andrew J Tatem
- Fogarty International Center, National Institutes of Health, Bethesda, MD, 20892, USA. .,Flowminder Foundation, Roslagsgatan 17, 113 55, Stockholm, Sweden. .,Geography and Environment, University of Southampton, University Road, Southampton, SO17 1BJ, UK.
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Kateera F, Ingabire CM, Hakizimana E, Kalinda P, Mens PF, Grobusch MP, Mutesa L, van Vugt M. Malaria, anaemia and under-nutrition: three frequently co-existing conditions among preschool children in rural Rwanda. Malar J 2015; 14:440. [PMID: 26542672 PMCID: PMC4635556 DOI: 10.1186/s12936-015-0973-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 10/28/2015] [Indexed: 11/23/2022] Open
Abstract
Background Malaria, anaemia and under-nutrition are three highly prevalent and frequently co-existing diseases that cause significant morbidity and mortality particularly among children aged less than 5 years. Currently, there is paucity of conclusive studies on the burden of and associations between malaria, anaemia and under-nutrition in Rwanda and comparable sub-Saharan and thus, this study measured the prevalence of malaria parasitaemia, anaemia and under-nutrition among preschool age children in a rural Rwandan setting and evaluated for interactions between and risk determinants for these three conditions. Methods A cross-sectional household (HH) survey involving children aged 6–59 months was conducted. Data on malaria parasitaemia, haemoglobin densities, anthropometry, demographics, socioeconomic status (SES) and malaria prevention knowledge and practices were collected. Results The prevalences of malaria parasitaemia and anaemia were 5.9 and 7.0 %, respectively, whilst the prevalence of stunting was 41.3 %. Malaria parasitaemia risk differed by age groups with odds ratio (OR) = 2.53; P = 0.04 for age group 24–35 months, OR = 3.5; P = 0.037 for age group 36–47 months, and OR = 3.03; P = 0.014 for age group 48–60 months, whilst a reduced risk was found among children living in high SES HHs (OR = 0.37; P = 0.029). Risk of anaemia was high among children aged ≥12 months, those with malaria parasitaemia (OR = 3.86; P ≤ 0.0001) and children living in HHs of lower SES. Overall, under-nutrition was not associated with malaria parasitaemia. Underweight was higher among males (OR = 1.444; P = 0.019) and children with anaemia (OR = 1.98; P = 0.004). Conclusions In this study group, four in 10 and one in 10 children were found stunted and underweight, respectively, in an area of low malaria transmission. Under-nutrition was not associated with malaria risk. While the high prevalence of stunting requires urgent response, reductions in malaria parasitaemia and anaemia rates may require, in addition to scaled-up use of insecticide-treated bed nets and indoor residual insecticide spraying, improvements in HH SES and better housing to reduce risk of malaria.
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Affiliation(s)
- Fredrick Kateera
- Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Academic Medical Centre, Meibergdreef 9, 1100 DE, Amsterdam, The Netherlands. .,Medical Research Centre Division, Rwanda Biomedical Centre, PO Box 7162, Kigali, Rwanda.
| | - Chantal M Ingabire
- Medical Research Centre Division, Rwanda Biomedical Centre, PO Box 7162, Kigali, Rwanda.
| | - Emmanuel Hakizimana
- Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Centre, Kigali, Rwanda.
| | - Parfait Kalinda
- Medical Research Centre Division, Rwanda Biomedical Centre, PO Box 7162, Kigali, Rwanda.
| | - Petra F Mens
- Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Academic Medical Centre, Meibergdreef 9, 1100 DE, Amsterdam, The Netherlands. .,Royal Tropical Institute, Koninklijk Instituut voor de Tropen, KIT Biomedical Research, Meibergdreef 39, 1105 AZ, Amsterdam, The Netherlands.
| | - Martin P Grobusch
- Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Academic Medical Centre, Meibergdreef 9, 1100 DE, Amsterdam, The Netherlands.
| | - Leon Mutesa
- College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda.
| | - Michèle van Vugt
- Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Academic Medical Centre, Meibergdreef 9, 1100 DE, Amsterdam, The Netherlands.
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Chitunhu S, Musenge E. Direct and indirect determinants of childhood malaria morbidity in Malawi: a survey cross-sectional analysis based on malaria indicator survey data for 2012. Malar J 2015; 14:265. [PMID: 26152223 PMCID: PMC4495946 DOI: 10.1186/s12936-015-0777-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 06/29/2015] [Indexed: 01/06/2023] Open
Abstract
Background Children under the age of five are most vulnerable to malaria (malaria is a major health challenge in sub-Saharan Africa) with a child dying every 30 s from malaria. Hampered socio-economic development, poverty, diseconomies of scale, marginalization, and exploitation are associated with malaria. Therefore establishing determinants of malaria in affected sub-Saharan populations is important in order to come up with informed interventions that will be effective in malaria control. Methods The study was a cross-sectional survey design based on data from the Malawi 2012 Malaria indicator Survey obtained from Demographic and Health Survey (DHS) programme website. The outcome variable was positive laboratory-based blood smear result for malaria in children less than 5 years, after an initial positive rapid malaria diagnostic test done at the homestead. Statistical modelling was done using survey logistic regression as well as generalized structural equation modelling (G-SEM) to analyse direct and indirect effects of malaria. Results The propensity score matched data had 1 325 children with 367 (27.7%) having blood smear positive malaria. Female children made up approximately 53% of the total study participants. Child related variables (age, haemoglobin and position in household) and household wealth index were significant directly and indirectly. Further on G-SEM based multivariable analysis showed socio-economic status (SES) [Odds ratio (OR) = 0.96, 95% Confidence interval (CI) = 0.92, 0.99] and primary level of education [OR = 0.50, 95% CI = 0.32, 0.77] were important direct and indirect determinants of malaria morbidity. Conclusion Socio-economic status and education are important factors that influence malaria control. These factors need to be taken into consideration when planning malaria control programmes in order to have effective programmes. Direct and indirect effect modelling can also provide an alternative modelling technique that incorporates surrogate confounders that may not be significant when modelled directly. This holistic approach is useful and will help in improving malaria control.
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Affiliation(s)
- Simangaliso Chitunhu
- Division of Epidemiology and Biostatistics, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, 27 St Andrews' Road, Parktown, Johannesburg, 2193, South Africa.
| | - Eustasius Musenge
- Division of Epidemiology and Biostatistics, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, 27 St Andrews' Road, Parktown, Johannesburg, 2193, South Africa.
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Memvanga PB, Tona GL, Mesia GK, Lusakibanza MM, Cimanga RK. Antimalarial activity of medicinal plants from the Democratic Republic of Congo: A review. JOURNAL OF ETHNOPHARMACOLOGY 2015; 169:76-98. [PMID: 25862959 DOI: 10.1016/j.jep.2015.03.075] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/11/2015] [Accepted: 03/12/2015] [Indexed: 06/04/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Malaria is the most prevalent parasitic disease and the foremost cause of morbidity and mortality in the Democratic Republic of Congo. For the management of this disease, a large Congolese population recourses to traditional medicinal plants. To date the efficacy and safety of many of these plants have been validated scientifically in rodent malaria models. In order to generate scientific evidence of traditional remedies used in the Democratic Republic of Congo for the management of malaria, and show the potential of Congolese plants as a major source of antimalarial drugs, this review highlights the antiplasmodial and toxicological properties of the Congolese antimalarial plants investigated during the period of 1999-2014. In doing so, a useful resource for further complementary investigations is presented. Furthermore, this review may pave the way for the research and development of several available and affordable antimalarial phytomedicines. MATERIALS AND METHODS In order to get information on the different studies, a Google Scholar and PubMed literature search was performed using keywords (malaria, Congolese, medicinal plants, antiplasmodial/antimalarial activity, and toxicity). Data from non-indexed journals, Master and Doctoral dissertations were also collected. RESULTS Approximately 120 extracts and fractions obtained from Congolese medicinal plants showed pronounced or good antiplasmodial activity. A number of compounds with interesting antiplasmodial properties were also isolated and identified. Some of these compounds constituted new scaffolds for the synthesis of promising antimalarial drugs. Interestingly, most of these extracts and compounds possessed high selective activity against Plasmodium parasites compared to mammalian cells. The efficacy and safety of several plant-derived products was confirmed in mice, and a good correlation was observed between in vitro and in vivo antimalarial activity. The formulation of several plant-derived products also led to some clinical trials and license of three plant-derived drugs (Manalaria(®), Nsansiphos(®), and Quinine Pharmakina(®)). CONCLUSION The obtained results partly justify and support the use of various medicinal plants to treat malaria in folk medicine in the Democratic Republic of Congo. Antimalarial plants used in Congolese traditional medicine represent an important source for the discovery and development of new antimalarial agents. However, in order to ensure the integration of a larger number of plant-derived products in the Congolese healthcare system, some parameters and trends should be considered in further researches, in agreement with the objectives of the "Traditional Medicine Strategy" proposed by the World Health Organization in 2013. These include evaluation of geographical and seasonal variation, investigation of reproductive biology, assessment of prophylactic antimalarial activity, evaluation of natural products as adjuvant antioxidant therapy for malaria, development of plant-based combination therapies and monitoring of herbal medicines in pharmacovigilance systems.
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Affiliation(s)
- Patrick B Memvanga
- University of Kinshasa, Faculty of Pharmaceutical Sciences, Laboratory of Pharmaceutics and Phytopharmaceutical Drugs Development, B.P. 212 Kinshasa XI, Democratic Republic of Congo.
| | - Gaston L Tona
- University of Kinshasa, Faculty of Pharmaceutical Sciences, Laboratory of Pharmacology and Therapeutics, B.P. 212 Kinshasa XI, Democratic Republic of Congo
| | - Gauthier K Mesia
- University of Kinshasa, Faculty of Pharmaceutical Sciences, Laboratory of Pharmacology and Therapeutics, B.P. 212 Kinshasa XI, Democratic Republic of Congo
| | - Mariano M Lusakibanza
- University of Kinshasa, Faculty of Pharmaceutical Sciences, Laboratory of Pharmacology and Therapeutics, B.P. 212 Kinshasa XI, Democratic Republic of Congo
| | - Richard K Cimanga
- University of Kinshasa, Faculty of Pharmaceutical Sciences, Laboratory of Pharmacognosy, B.P. 212 Kinshasa XI, Democratic Republic of Congo; University of Antwerp, Department of Pharmaceutical Sciences, Laboratory of Pharmacognosy and Pharmaceutical Analysis, Universiteitsplein 1, B-2610 Antwerp, Belgium
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Perez-Heydrich C, Warren JL, Burgert CR, Emch ME. Influence of Demographic and Health Survey Point Displacements on Raster-Based Analyses. SPATIAL DEMOGRAPHY 2015; 4:135-153. [PMID: 29888316 DOI: 10.1007/s40980-015-0013-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
With this paper we explore the sensitivity of study results to spatial displacements associated with Demographic and Health Survey (DHS) data in research that integrates ancillary raster data. Through simulation studies, we found that the impact of DHS point displacements on raster-based analyses can be moderated through the generation of covariates representing average values from neighborhood buffers. Additionally, raster surface characteristics (i.e., spatial smoothness) were found to affect the extent of bias introduced through point displacements. Although simple point extraction produced unbiased estimates in analyses involving smooth continuous surfaces, it is not recommended in analyses that involve categorical raster surfaces.
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Affiliation(s)
| | - Joshua L Warren
- Department of Biostatistics, Yale School of Public Health, Yale University, New Haven, CT, USA
| | | | - Michael E Emch
- Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Komen K, Olwoch J, Rautenbach H, Botai J, Adebayo A. Long-run relative importance of temperature as the main driver to malaria transmission in Limpopo Province, South Africa: a simple econometric approach. ECOHEALTH 2015; 12:131-43. [PMID: 25515074 DOI: 10.1007/s10393-014-0992-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 10/10/2014] [Accepted: 10/13/2014] [Indexed: 05/15/2023]
Abstract
Malaria in Limpopo Province of South Africa is shifting and now observed in originally non-malaria districts, and it is unclear whether climate change drives this shift. This study examines the distribution of malaria at district level in the province, determines direction and strength of the linear relationship and causality between malaria with the meteorological variables (rainfall and temperature) and ascertains their short- and long-run variations. Spatio-temporal method, Correlation analysis and econometric methods are applied. Time series monthly meteorological data (1998-2007) were obtained from South Africa Weather Services, while clinical malaria data came from Malaria Control Centre in Tzaneen (Limpopo Province) and South African Department of Health. We find that malaria changes and pressures vary in different districts with a strong positive correlation between temperature with malaria, r = 0.5212, and a weak positive relationship for rainfall, r = 0.2810. Strong unidirectional causality runs from rainfall and temperature to malaria cases (and not vice versa): F (1, 117) = 3.89, ρ = 0.0232 and F (1, 117) = 20.08, P < 0.001 and between rainfall and temperature, a bi-directional causality exists: F (1, 117) = 19.80; F (1,117) = 17.14, P < 0.001, respectively, meaning that rainfall affects temperature and vice versa. Results show evidence of strong existence of a long-run relationship between climate variables and malaria, with temperature maintaining very high level of significance than rainfall. Temperature, therefore, is more important in influencing malaria transmission in Limpopo Province.
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Affiliation(s)
- Kibii Komen
- Geoinformatics and Meteorology - Center for Environmental Studies, Department of Geography, University of Pretoria, Pretoria, 0002, South Africa,
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Wumba RD, Zanga J, Aloni MN, Mbanzulu K, Kahindo A, Mandina MN, Ekila MB, Mouri O, Kendjo E. Interactions between malaria and HIV infections in pregnant women: a first report of the magnitude, clinical and laboratory features, and predictive factors in Kinshasa, the Democratic Republic of Congo. Malar J 2015; 14:82. [PMID: 25884992 PMCID: PMC4336768 DOI: 10.1186/s12936-015-0598-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Accepted: 01/30/2015] [Indexed: 11/12/2022] Open
Abstract
Background HIV and malaria are among the leading causes of morbidity and mortality during pregnancy in Africa. However, data from Congolese pregnant women are lacking. The aim of the study was to determine the magnitude, predictive factors, clinical, biologic and anthropometric consequences of malaria infection, HIV infection, and interactions between malaria and HIV infections in pregnant women. Methods A cross-sectional study was conducted among pregnant women admitted and followed up at Camp Kokolo Military Hospital from 2009 to 2012 in Kinshasa, the Democratic Republic of Congo. Differences in means between malaria-positive and malaria-negative cases or between HIV-positive and HIV-negative cases were compared using the Student’s t-test or a non-parametric test, if appropriate. Categorical variables were compared using the Chi-square or Fisher’s exact test, if appropriate. Backward multivariable analysis was used to evaluate the potential risk factors of malaria and HIV infections. The odds ratios with their 95% confidence interval (95% CI) were estimated to measure the strengths of the associations. Analyses resulting in values of P < 0.05 were considered significant. Results A malaria infection was detected in 246/332 (74.1%) pregnant women, and 31.9% were anaemic. Overall, 7.5% (25/332) of mothers were infected by HIV, with a median CD4 count of 375 (191; 669) cells/μL. The mean (±SD) birth weight was 2,613 ± 227 g, with 35.7% of newborns weighing less than 2,500 g (low birth weight). Low birth weight, parity and occupation were significantly different between malaria-infected and uninfected women in adjusted models. However, fever, anemia, placenta previa, marital status and district of residence were significantly associated to HIV infection. Conclusion The prevalence of malaria infection was high in pregnant women attending the antenatal facilities or hospitalized and increased when associated with HIV infection.
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Affiliation(s)
- Roger D Wumba
- Department of Tropical Medicine, Infectious and Parasitic Diseases, Department of Parasitology, University Clinic of Kinshasa, Faculty of Medicine, University of Kinshasa, Kinshasa, Congo.
| | - Josué Zanga
- Department of Tropical Medicine, Infectious and Parasitic Diseases, Department of Parasitology, University Clinic of Kinshasa, Faculty of Medicine, University of Kinshasa, Kinshasa, Congo.
| | - Michel N Aloni
- Department of Pediatrics, University Hospital of Kinshasa, Faculty of Medicine, University of Kinshas, Kinshasa, the Democratic Republic of Congo.
| | - Kennedy Mbanzulu
- Department of Tropical Medicine, Infectious and Parasitic Diseases, Department of Parasitology, University Clinic of Kinshasa, Faculty of Medicine, University of Kinshasa, Kinshasa, Congo.
| | - Aimé Kahindo
- Department of Tropical Medicine, Infectious and Parasitic Diseases, Department of Parasitology, University Clinic of Kinshasa, Faculty of Medicine, University of Kinshasa, Kinshasa, Congo.
| | - Madone N Mandina
- Department of Internal Medicine, University Hospital of Kinshasa, Faculty of Medicine, University of Kinshasa, Kinshasa, the Democratic Republic of Congo.
| | - Mathilde B Ekila
- Department of Internal Medicine, University Hospital of Kinshasa, Faculty of Medicine, University of Kinshasa, Kinshasa, the Democratic Republic of Congo.
| | - Oussama Mouri
- Centre Nationale de Référence du Paludisme, AP-HP, CHU Pitie Salpêtrière-Charles Foix, 47, boulevard de l'Hôpital, 75651, Paris, Cedex 13, France. .,Laboratory of Parasitology and Mycology, Pitié Salpêtrière Hospital, Public Assistance-Hospitals of Paris, Pierre and Marie Curie University, Paris, France.
| | - Eric Kendjo
- Centre Nationale de Référence du Paludisme, AP-HP, CHU Pitie Salpêtrière-Charles Foix, 47, boulevard de l'Hôpital, 75651, Paris, Cedex 13, France. .,Laboratory of Parasitology and Mycology, Pitié Salpêtrière Hospital, Public Assistance-Hospitals of Paris, Pierre and Marie Curie University, Paris, France. .,Department of Parasitology, Mycology and Tropical Medicine, Faculty of Medicine, University of Health Sciences, Libreville, Gabon. .,Institute of Tropical Medicine, University of Tubingen, Tubingen, Germany.
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Kateera F, Mens PF, Hakizimana E, Ingabire CM, Muragijemariya L, Karinda P, Grobusch MP, Mutesa L, van Vugt M. Malaria parasite carriage and risk determinants in a rural population: a malariometric survey in Rwanda. Malar J 2015; 14:16. [PMID: 25604040 PMCID: PMC4308829 DOI: 10.1186/s12936-014-0534-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Accepted: 12/27/2014] [Indexed: 01/05/2023] Open
Abstract
Background Based on routine health facility case data, Rwanda has achieved a significant malaria burden reduction in the past ten years. However, community-based malaria parasitaemia burden and reasons for continued residual infections, despite a high coverage of control interventions, have yet to be characterized. Measurement of malaria parasitaemia rates and evaluation of associated risk factors among asymptomatic household members in a rural community in Rwanda were conducted. Methods A malariometric household survey was conducted between June and November 2013, involving 12,965 persons living in 3,989 households located in 35 villages in a sector in eastern Rwanda. Screening for malaria parasite carriage and collection of demographic, socio-economic, house structural features, and prior fever management data, were performed. Logistic regression models with adjustment for within- and between-households clustering were used to assess malaria parasitaemia risk determinants. Results Overall, malaria parasitaemia was found in 652 (5%) individuals, with 518 (13%) of households having at least one parasitaemic member. High malaria parasite carriage risk was associated with being male, child or adolescent (age group 4–15), reported history of fever and living in a household with multiple occupants. A malaria parasite carriage risk-protective effect was associated with living in households of, higher socio-economic status, where the head of household was educated and where the house floor or walls were made of cement/bricks rather than mud/earth/wood materials. Parasitaemia cases were found to significantly cluster in the Gikundamvura area that neighbours marshlands. Conclusion Overall, Ruhuha Sector can be classified as hypo-endemic, albeit with a particular ‘cell of villages’ posing a higher risk for malaria parasitaemia than others. Efforts to further reduce transmission and eventually eliminate malaria locally should focus on investments in programmes that improve house structure features (that limit indoor malaria transmission), making insecticide-treated bed nets and indoor residual spraying implementation more effective.
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Affiliation(s)
- Fredrick Kateera
- Centre of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Centre, Meibergdreef 9, Amsterdam, 1100 DE, The Netherlands.
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Patel JC, Taylor SM, Juliao PC, Parobek CM, Janko M, Gonzalez LD, Ortiz L, Padilla N, Tshefu AK, Emch M, Udhayakumar V, Lindblade K, Meshnick SR. Genetic Evidence of Importation of Drug-Resistant Plasmodium falciparum to Guatemala from the Democratic Republic of the Congo. Emerg Infect Dis 2015; 20:932-40. [PMID: 24856348 PMCID: PMC4036788 DOI: 10.3201/eid2006.131204] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Molecular markers and population genetics were effective tracking tools. Imported malaria threatens control and elimination efforts in countries that have low rates of transmission. In 2010, an outbreak of Plasmodium falciparum malaria was reported among United Nations peacekeeping soldiers from Guatemala who had recently returned from the Democratic Republic of the Congo (DRC). Epidemiologic evidence suggested that the soldiers were infected in the DRC, but local transmission could not be ruled out in all cases. We used population genetic analyses of neutral microsatellites to determine the outbreak source. Genetic relatedness was compared among parasites found in samples from the soldiers and parasite populations collected in the DRC and Guatemala; parasites identified in the soldiers were more closely related to those from the DRC. A phylogenetic clustering analysis confirms this identification with >99.9% confidence. Thus, results support the hypothesis that the soldiers likely imported malaria from the DRC. This study demonstrates the utility of molecular genotyping in outbreak investigations.
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Okebe J, Affara M, Correa S, Muhammad AK, Nwakanma D, Drakeley C, D’Alessandro U. School-based countrywide seroprevalence survey reveals spatial heterogeneity in malaria transmission in the Gambia. PLoS One 2014; 9:e110926. [PMID: 25338083 PMCID: PMC4206471 DOI: 10.1371/journal.pone.0110926] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 09/25/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND As the geographical distribution of malaria transmission becomes progressively clustered, identifying residual pockets of transmission is important for research and for targeting interventions. Malarial antibody-based surveillance is increasingly recognised as a valuable complement to classic methods for the detection of infection foci especially at low transmission levels. The study presents serological evidence for transmission heterogeneity among school children in The Gambia measured during the dry, non-transmission season. METHODS Healthy primary school children were randomly selected from 30 schools across the country and screened for malaria infection (microscopy) and antimalarial antibodies (MSP119). Antibody distribution was modelled using 2-component finite mixture model with cut-off for positivity from pooled sera set at 2-standard deviation from the mean of the first component. Factors associated with a positive serological status were identified in a univariate model and then combined in a multilevel mixed-effects logistic regression model, simultaneously adjusting for variations between individuals and school. RESULTS A total of 4140 children, 1897 (46%) boys, were enrolled with mean age of 10.2 years (SD 2.6, range 4-20 years). Microscopy results available for 3640 (87.9%) children showed that 1.9% (69) were positive for Plasmodium falciparum infections, most of them (97.1%, 67/69) asymptomatic. The overall seroprevalence was 12.7% (527/4140) with values for the schools ranging from 0.6% to 43.8%. Age (OR 1.12, 95% CI 1.07-1.16,) and parasite carriage (OR 3.36, 95% CI 1.95-5.79) were strongly associated with seropositivity. CONCLUSION Serological responses to malaria parasites could identify individuals who were or had been infected, and clusters of residual transmission. Field-adapted antibody tests able to guide mass screening and treatment campaigns would be extremely useful.
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Affiliation(s)
- Joseph Okebe
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
- * E-mail:
| | - Muna Affara
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
| | - Simon Correa
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
| | - Abdul Khalie Muhammad
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
| | - Davis Nwakanma
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
| | - Chris Drakeley
- Department of Immunology and Infection, London school of Hygiene and Tropical Medicine, London, United Kingdom
| | - Umberto D’Alessandro
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
- Department of Disease Control, Faculty of infectious and Tropical Diseases, London school of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Public health, Institute of Tropical Medicine, Antwerp, Belgium
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Aloni MN, Tshimanga BK, Ekulu PM, Ehungu JLG, Ngiyulu RM. Malaria, clinical features and acute crisis in children suffering from sickle cell disease in resource-limited settings: a retrospective description of 90 cases. Pathog Glob Health 2014; 107:198-201. [PMID: 23816320 DOI: 10.1179/2047773213y.0000000089] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
BACKGROUND The prevalence of sickle cell disease (SCD) is extremely high in the Democratic Republic of Congo (DRC). Despite the high prevalence of this disease in our midst, there has been no report on the clinical features in the sickle cell pediatric population suffering from malaria in our midst. METHODS A retrospective survey of records from the Department of Paediatrics of the University Hospital of Kinshasa, Kinshasa, Democratic Republic of Congo, was done for the period 1998–2008. For the 10 years studied, 108 children with SCD were reviewed and the data of those who developed malaria during admission were retrieved and analyzed. RESULTS Of the 90 homozygous sickle cell children with malaria, fever, pallor, and jaundice were the commonly-found symptoms. Lethargy, severe anemia, respiratory distress, splenomegaly, hepatomegaly,digestive disorders, and prostration were common in children under 5 years, with significant difference (P, 0.05) to the older children. Transfusion because of to severe anemia was found necessary in 54.4% of cases. No case of cerebral malaria was found. Blackwater fever was a rare event. Hand–foot syndrome was present in 12.8% of patients, exclusively in those less than 5 years old. Pain crisis was associated in 46 cases (51.1%). Pain crisis was particularly present in SCD children less than 5 years of age (74.5% vs 25.6%, P , 0.001). No death was observed in this series. CONCLUSION We conclude that the acute crisis related to SCD is more common in children less than 5 years of age. High risk of a requirement for blood transfusion was found in young children. Anti-malarial prophylaxis is advocated in Kinshasa.
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Affiliation(s)
- Michel Ntetani Aloni
- Division of Hemato-oncology and Nephrology, Department of Paediatrics, University Hospital of Kinshasa, School of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo.
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Kumar DS, Andimuthu R, Rajan R, Venkatesan MS. Spatial trend, environmental and socioeconomic factors associated with malaria prevalence in Chennai. Malar J 2014; 13:14. [PMID: 24400592 PMCID: PMC3893554 DOI: 10.1186/1475-2875-13-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 01/05/2014] [Indexed: 11/28/2022] Open
Abstract
Background Urban malaria is considered to be one of the most significant infectious diseases due to varied socioeconomic problems especially in tropical countries like India. Among the south Indian cities, Chennai is endemic for malaria. The present study aimed to identify the hot spots of malaria prevalence and the relationship with other factors in Chennai during 2005-2011. Methods Data on zone-wise and ward-wise monthly malaria positive cases were collected from the Vector Control Office, Chennai Corporation, for the year 2005 to 2011 and verified using field data. This data was used to calculate the prevalence among thousand people. Hotspot analysis for all the years in the study period was done to observe the spatial trend. Association of environmental factors like altitude, population density and climatic variables was assessed using ArcGIS 9.3 version and SPSS 11.5. Pearson’s correlation of climate parameters at 95% and 99% was considered to be the most significant. Social parameters of the highly malaria prone region were evaluated through a structured random questionnaire field survey. Results Among the ten zones of Chennai Corporation, Basin Bridge zone showed high malaria prevalence during the study period. The ‘hotspot’ analysis of malaria prevalence showed the emergence of newer hotspots in the Adyar zone. These hotspots of high prevalence are places of moderately populated and moderately elevated areas. The prevalence of malaria in Chennai could be due to rainfall and temperature, as there is a significant correlation with monthly rainfall and one month lag of monthly mean temperature. Further it has been observed that the socioeconomic status of people in the malaria hotspot regions and unhygienic living conditions were likely to aggravate the malaria problem. Conclusion Malaria hotspots will be the best method to use for targeting malaria control activities. Proper awareness and periodical monitoring of malaria is one of the quintessential steps to control this infectious disease. It has been argued that identifying the key environmental conditions favourable for the occurrence and spread of malaria must be integrated and documented to aid future predictions of malaria in Chennai.
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Affiliation(s)
- Divya Subash Kumar
- Centre for Climate Change and Adaptation Research, Anna University, Chennai, Sardar Patel Road, Guindy 600 025, Chennai, Tamil Nadu, India.
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Mapping amyotrophic lateral sclerosis lake risk factors across northern New England. Int J Health Geogr 2014; 13:1. [PMID: 24383521 PMCID: PMC3922844 DOI: 10.1186/1476-072x-13-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 12/16/2013] [Indexed: 12/11/2022] Open
Abstract
Background Amyotrophic lateral sclerosis (ALS) is a progressive, fatal neurodegenerative disease with a lifetime risk of developing as 1 in 700. Despite many recent discoveries about the genetics of ALS, the etiology of sporadic ALS remains largely unknown with gene-environment interaction suspected as a driver. Water quality and the toxin beta methyl-amino-alanine produced by cyanobacteria are suspected environmental triggers. Our objective was to develop an eco-epidemiological modeling approach to characterize the spatial relationships between areas of higher than expected ALS incidence and lake water quality risk factors derived from satellite remote sensing as a surrogate marker of exposure. Methods Our eco-epidemiological modeling approach began with implementing a spatial clustering analysis that was informed by local indicators of spatial autocorrelation to identify locations of normalized excess ALS counts at the census tract level across northern New England. Next, water quality data for all lakes over 6 hectares (n = 4,453) were generated using Landsat TM band ratio regression techniques calibrated with in situ lake sampling. Derived lake water quality risk maps included chlorophyll-a (Chl-a), Secchi depth (SD), and total nitrogen (TN). Finally, a spatially-aware logistic regression modeling approach was executed characterizing relationships between the derived lake water quality metrics and ALS hot spots. Results Several distinct ALS hot spots were identified across the region. Remotely sensed lake water quality indicators were successfully derived; adjusted R2 values ranged between 0.62-0.88 for these indicators based on out-of-sample validation. Map products derived from these indicators represent the first wall-to-wall metrics of lake water quality across the region. Logistic regression modeling of ALS case membership in localized hot spots across the region, i.e., census tracts with higher than expected ALS counts, showed the following: increasing average SD within a radius of 30 km corresponds with a decrease in the odds of belonging to an ALS hot spot by 59%; increasing average TN within a radius of 30 km and average Chl-a concentration within a radius of 10 km correspond with increased odds of belonging to an ALS hot spot by 167% and 4%, respectively. Conclusions The strengths of satellite remote sensing information can help overcome traditional field limitations and spatiotemporal data gaps to provide the public health community valuable exposure data. Geographic scale needs to be diligently considered when evaluating relationships among ecological processes, risk factors, and human health outcomes. Broadly, we found that poorer lake water quality was significantly associated with increased odds of belonging to an ALS cluster in the region. These findings support the hypothesis that sporadic ALS (sALS) can, in part, be triggered by environmental water-quality indicators and lake conditions that promote harmful algal blooms.
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