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Bradley L, Yewhalaw D, Hemming-Schroeder E, Jeang B, Lee MC, Zemene E, Degefa T, Lo E, King C, Kazura J, Yan G. Epidemiology of Plasmodium vivax in Duffy negatives and Duffy positives from community and health centre collections in Ethiopia. Malar J 2024; 23:76. [PMID: 38486245 PMCID: PMC10941426 DOI: 10.1186/s12936-024-04895-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 02/28/2024] [Indexed: 03/17/2024] Open
Abstract
BACKGROUND Malaria remains a significant cause of morbidity and mortality in Ethiopia with an estimated 3.8 million cases in 2021 and 61% of the population living in areas at risk of malaria transmission. Throughout the country Plasmodium vivax and Plasmodium falciparum are co-endemic, and Duffy expression is highly heterogeneous. The public health significance of Duffy negativity in relation to P. vivax malaria in Ethiopia, however, remains unclear. This study seeks to explore the prevalence and rates of P. vivax malaria infection across Duffy phenotypes in clinical and community settings. METHODS A total of 9580 and 4667 subjects from community and health facilities from a malaria endemic site and an epidemic-prone site in western Ethiopia were enrolled and examined for P. vivax infection and Duffy expression from February 2018 to April 2021. Association between Duffy expression, P. vivax and P. falciparum infections were examined for samples collected from asymptomatic community volunteers and symptomatic subjects from health centres. RESULTS Infection rate of P. vivax among Duffy positives was 2-22 fold higher than Duffy negatives in asymptomatic volunteers from the community. Parasite positivity rate was 10-50 fold higher in Duffy positives than Duffy negatives among samples collected from febrile patients attending health centres and mixed P. vivax and P. falciparum infections were significantly more common than P. vivax mono infections among Duffy negative individuals. Plasmodium vivax parasitaemia measured by 18sRNA parasite gene copy number was similar between Duffy positives and Duffy negatives. CONCLUSIONS Duffy negativity does not offer complete protection against infection by P. vivax, and cases of P. vivax in Duffy negatives are widespread in Ethiopia, being found in asymptomatic volunteers from communities and in febrile patients from health centres. These findings offer evidence for consideration when developing control and intervention strategies in areas of endemic P. vivax and Duffy heterogeneity.
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Affiliation(s)
- Lauren Bradley
- Department of Ecology and Evolutionary Biology, School of Biological Sciences, University of California Irvine, Irvine, CA, 92697, USA
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, 5195, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Centre, Jimma University, Jimma, Ethiopia
| | - Elizabeth Hemming-Schroeder
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Brook Jeang
- Department of Ecology and Evolutionary Biology, School of Biological Sciences, University of California Irvine, Irvine, CA, 92697, USA
| | - Ming-Chieh Lee
- Department of Ecology and Evolutionary Biology, School of Biological Sciences, University of California Irvine, Irvine, CA, 92697, USA
| | - Endalew Zemene
- Tropical and Infectious Diseases Research Centre, Jimma University, Jimma, Ethiopia
| | - Teshome Degefa
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Eugenia Lo
- Department of Microbiology and Immunology, Drexel University, Philadelphia, PA, 19104, USA
| | - Christopher King
- Center for Global Health and Disease, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - James Kazura
- Center for Global Health and Disease, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Guiyun Yan
- Department of Ecology and Evolutionary Biology, School of Biological Sciences, University of California Irvine, Irvine, CA, 92697, USA.
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA.
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Zhou G, Githure J, Lee MC, Zhong D, Wang X, Atieli H, Githeko AK, Kazura J, Yan G. Malaria transmission heterogeneity in different eco-epidemiological areas of western Kenya: a region-wide observational and risk classification study for adaptive intervention planning. Malar J 2024; 23:74. [PMID: 38475793 PMCID: PMC10935946 DOI: 10.1186/s12936-024-04903-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 03/05/2024] [Indexed: 03/14/2024] Open
Abstract
BACKGROUND Understanding of malaria ecology is a prerequisite for designing locally adapted control strategies in resource-limited settings. The aim of this study was to utilize the spatial heterogeneity in malaria transmission for the designing of adaptive interventions. METHODS Field collections of clinical malaria incidence, asymptomatic Plasmodium infection, and malaria vector data were conducted from 108 randomly selected clusters which covered different landscape settings including irrigated farming, seasonal flooding area, lowland dryland farming, and highlands in western Kenya. Spatial heterogeneity of malaria was analyzed and classified into different eco-epidemiological zones. RESULTS There was strong heterogeneity and detected hot/cold spots in clinical malaria incidence, Plasmodium prevalence, and vector abundance. The study area was classified into four zones based on clinical malaria incidence, parasite prevalence, vector density, and altitude. The two irrigated zones have either the highest malaria incidence, parasite prevalence, or the highest malaria vector density; the highlands have the lowest vector density and parasite prevalence; and the dryland and flooding area have the average clinical malaria incidence, parasite prevalence and vector density. Different zones have different vector species, species compositions and predominant species. Both indoor and outdoor transmission may have contributed to the malaria transmission in the area. Anopheles gambiae sensu stricto (s.s.), Anopheles arabiensis, Anopheles funestus s.s., and Anopheles leesoni had similar human blood index and malaria parasite sporozoite rate. CONCLUSION The multi-transmission-indicator-based eco-epidemiological zone classifications will be helpful for making decisions on locally adapted malaria interventions.
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Affiliation(s)
- Guofa Zhou
- Program in Public Health, University of California, Irvine, CA, USA.
| | - John Githure
- Sub-Saharan International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, Kenya
| | - Ming-Chieh Lee
- Program in Public Health, University of California, Irvine, CA, USA
| | - Daibin Zhong
- Program in Public Health, University of California, Irvine, CA, USA
| | - Xiaoming Wang
- Program in Public Health, University of California, Irvine, CA, USA
| | - Harrysone Atieli
- Sub-Saharan International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, Kenya
| | - Andrew K Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - James Kazura
- Center for Global Health and Diseases, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA, USA
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Bradley L, Yewhalaw D, Hemming-Schroeder E, Embury P, Lee MC, Zemene E, Degefa T, King C, Kazura J, Yan G, Dent A. Determination of Plasmodium vivax and Plasmodium falciparum Malaria Exposure in Two Ethiopian Communities and Its Relationship to Duffy Expression. Am J Trop Med Hyg 2023; 109:1028-1035. [PMID: 37918005 PMCID: PMC10622468 DOI: 10.4269/ajtmh.22-0644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 07/16/2023] [Indexed: 11/04/2023] Open
Abstract
Despite historical dogma that Duffy blood group negativity of human erythrocytes confers resistance to Plasmodium vivax blood stage infection, cases of P. vivax malaria and asymptomatic blood stage infection (subclinical malaria) have recently been well documented in Duffy-negative individuals throughout Africa. However, the impact of Duffy negativity on the development of naturally acquired immunity to P. vivax remains poorly understood. We examined antibody reactivity to P. vivax and P. falciparum antigens at two field sites in Ethiopia and assessed Duffy gene expression by polymerase chain reaction amplification and sequencing of the GATA-1 transcription factor-binding site of the Duffy antigen receptor for chemokines (DARC) gene promotor region that is associated with silencing of erythroid cell transcription and absent protein expression. Antibodies to three of the four P. vivax blood stage antigens examined, RBP2b, EBP2, and DBPIISal-1, were significantly lower (P < 0.001) in Duffy-negative individuals relative to Duffy-positive individuals. In stark contrast, no clear pattern was found across Duffy-negative and Duffy-positive genotypes for P. falciparum antibodies. We conclude that lack of erythroid Duffy expression is associated with reduced serologic responses, indicative of less naturally acquired immunity and less cumulative exposure to blood stage P. vivax parasites relative to Duffy positive individuals living in the same communities.
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Affiliation(s)
- Lauren Bradley
- Department of Ecology and Evolutionary Biology, School of Biological Sciences, University of California, Irvine, California
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | | | - Paula Embury
- Center for Global Health and Disease, Case Western Reserve University, Cleveland, Ohio
| | - Ming-Chieh Lee
- Program in Public Health, College of Health Sciences, University of California, Irvine, California
| | - Endalew Zemene
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Teshome Degefa
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Christopher King
- Center for Global Health and Disease, Case Western Reserve University, Cleveland, Ohio
| | - James Kazura
- Center for Global Health and Disease, Case Western Reserve University, Cleveland, Ohio
| | - Guiyun Yan
- Department of Ecology and Evolutionary Biology, School of Biological Sciences, University of California, Irvine, California
- Program in Public Health, College of Health Sciences, University of California, Irvine, California
| | - Arlene Dent
- Center for Global Health and Disease, Case Western Reserve University, Cleveland, Ohio
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Bradley L, Yewhalaw D, Hemming-Schroeder E, Jeang B, Lee MC, Zemene E, Degefa T, Lo E, King C, Kazura J, Yan G. Comparison of Plasmodium Vivax Infections in Duffy Negatives From Community and Health Center Collections in Ethiopia. Res Sq 2023:rs.3.rs-3385916. [PMID: 37886593 PMCID: PMC10602065 DOI: 10.21203/rs.3.rs-3385916/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
Background Malaria remains a significant cause of morbidity and mortality in Ethiopia with an estimated 4.2 million annual cases and 61% of the population living in areas at risk of malaria transmission. Throughout the country Plasmodium vivax and P. falciparum are co-endemic, and Duffy expression is highly heterogeneous. The public health significance of Duffy negativity in relation to P. vivax malaria in Ethiopia, however, remains unclear. Methods A total of 9,580 and 4,667 subjects from community and health facilities from a malaria endemic site and an epidemic-prone site in western Ethiopia were enrolled and examined for P. vivax infection and Duffy expression. Association between Duffy expression, P. vivax and P. falciparum infections were examined for samples collected from asymptomatic community volunteers and symptomatic subjects from health centers. Results Among the community-based cross-sectional samples, infection rate of P. vivax among the Duffy positives was 2-22 fold higher than among the Duffy negatives. Parasite positivity rate was 10-50 fold higher in Duffy positive than Duffy negatives among samples collected from the health center settings and mixed P. vivax and P. falciparum infections were significantly more common than P. vivax mono infections among Duffy negative individuals. P. vivax parasitemia measured by 18sRNA parasite gene copy number was similar between Duffy positives and Duffy negatives. Conclusions Duffy negativity does not offer complete protection against infection by P. vivax, and cases of P. vivax in Duffy negatives are widespread in Ethiopia, being found in asymptomatic volunteers from communities and in febrile patients from health centers. These findings offer evidence for consideration when developing control and intervention strategies in areas of endemic P. vivax and Duffy heterogeneity.
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Atieli HE, Zhou G, Zhong D, Wang X, Lee MC, Yaro AS, Diallo M, Githure J, Kazura J, Lehmann T, Yan G. Wind-assisted high-altitude dispersal of mosquitoes and other insects in East Africa. J Med Entomol 2023; 60:698-707. [PMID: 37094808 PMCID: PMC10337859 DOI: 10.1093/jme/tjad033] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 03/12/2023] [Accepted: 03/22/2023] [Indexed: 05/03/2023]
Abstract
Knowledge of insect dispersal is relevant to the control of agricultural pests, vector-borne transmission of human and veterinary pathogens, and insect biodiversity. Previous studies in a malaria endemic area of the Sahel region in West Africa revealed high-altitude, long-distance migration of insects and various mosquito species. The objective of the current study was to assess whether similar behavior is exhibited by mosquitoes and other insects around the Lake Victoria basin region of Kenya in East Africa. Insects were sampled monthly from dusk to dawn over 1 year using sticky nets suspended on a tethered helium-filled balloon. A total of 17,883 insects were caught on nets tethered at 90, 120, and 160 m above ground level; 818 insects were caught in control nets. Small insects (<0.5 cm, n = 15,250) were predominant regardless of height compared with large insects (>0.5 cm, n = 2,334) and mosquitoes (n = 299). Seven orders were identified; dipteran was the most common. Barcoding molecular assays of 184 mosquitoes identified 7 genera, with Culex being the most common (65.8%) and Anopheles being the least common (5.4%). The survival rate of mosquitoes, experimentally exposed to high-altitude overnight, was significantly lower than controls maintained in the laboratory (19% vs. 85%). There were no significant differences in mosquito survival and oviposition rate according to capture height. These data suggest that windborne dispersal activity of mosquito vectors of malaria and other diseases occurs on a broad scale in sub-Saharan Africa.
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Affiliation(s)
- Harrysone E Atieli
- Sub-Saharan International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, Kenya
| | - Guofa Zhou
- Program in Public Health, University of California, Irvine, CA, USA
| | - Daibin Zhong
- Program in Public Health, University of California, Irvine, CA, USA
| | - Xiaoming Wang
- Program in Public Health, University of California, Irvine, CA, USA
| | - Ming-chieh Lee
- Program in Public Health, University of California, Irvine, CA, USA
| | - Alpha S Yaro
- Malaria Research and Training Center (MRTC)/Faculty of Medicine, Pharmacy and Odonto-Stomatology, Bamako, Mali
| | - Moussa Diallo
- Malaria Research and Training Center (MRTC)/Faculty of Medicine, Pharmacy and Odonto-Stomatology, Bamako, Mali
| | - John Githure
- Sub-Saharan International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, Kenya
| | - James Kazura
- Center for Global Health and Diseases, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Tovi Lehmann
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA, USA
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Jeang B, Lee MC, Embury P, Yewhalaw D, Narum D, King C, Tham WH, Kazura J, Yan G, Dent A. Serological Markers of Exposure to Plasmodium falciparum and Plasmodium vivax Infection in Southwestern Ethiopia. Am J Trop Med Hyg 2023; 108:871-881. [PMID: 37037443 PMCID: PMC10160885 DOI: 10.4269/ajtmh.22-0645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 01/22/2023] [Indexed: 04/12/2023] Open
Abstract
As malaria control and elimination efforts ramp up in Ethiopia, more sensitive tools for assessing exposure to coendemic Plasmodium falciparum and Plasmodium vivax are needed to accurately characterize malaria risk and epidemiology. Serological markers have been increasingly explored as cost-effective tools for measuring transmission intensity and evaluating intervention effectiveness. The objectives of this study were to evaluate the efficacy of a panel of 10 serological markers as a proxy for malaria exposure and to determine underlying risk factors of seropositivity. We conducted cross-sectional surveys in two sites of contrasting malaria transmission intensities in southwestern Ethiopia: Arjo in Oromia Region (low transmission) and Gambella in Gambella Regional State (moderate transmission). We measured antibody reactivity against six P. falciparum (AMA-1, CSP, EBA175RIII-V, MSP-142, MSP-3, RH2ab) and four P. vivax (DBPII[Sal1], EBP2, MSP-119, RBP2b) targets. We used mixed effects logistic regressions to assess predictors of seropositivity. Plasmodium spp. infection prevalence by quantitative polymerase chain reaction was 1.36% in Arjo and 10.20% in Gambella. Seroprevalence and antibody levels against all 10 antigens were higher in Gambella than in Arjo. We observed spatial heterogeneities in seroprevalence across Arjo and smaller variations across Gambella. Seroprevalence in both sites was lowest against PfCSP and highest against PfAMA-1, PfMSP-142, and PvMSPS-119. Male sex, age, and agricultural occupation were positively associated with seropositivity in Arjo; associations were less pronounced in Gambella. Our findings demonstrate that seroprevalence and antibody levels to specific Plasmodium antigens can be used to identify high-risk groups and geographical areas where interventions to reduce malaria transmission should be implemented.
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Affiliation(s)
- Brook Jeang
- Program in Public Health, University of California Irvine, Irvine, California
| | - Ming-Chieh Lee
- Program in Public Health, University of California Irvine, Irvine, California
| | - Paula Embury
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - David Narum
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Christopher King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Wai-Hong Tham
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - James Kazura
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Guiyun Yan
- Program in Public Health, University of California Irvine, Irvine, California
| | - Arlene Dent
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
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Otambo WO, Ochwedo KO, Omondi CJ, Lee MC, Wang C, Atieli H, Githeko AK, Zhou G, Kazura J, Githure J, Yan G. Community case management of malaria in Western Kenya: performance of community health volunteers in active malaria case surveillance. Malar J 2023; 22:83. [PMID: 36890544 PMCID: PMC9993668 DOI: 10.1186/s12936-023-04523-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/03/2023] [Indexed: 03/10/2023] Open
Abstract
BACKGROUND In western Kenya, not all malaria cases are reported as stipulated in the community case management of malaria (CCMm) strategy. This underreporting affects the equity distribution of malaria commodities and the evaluation of interventions. The current study aimed to evaluate the effectiveness of community health volunteers' active case detection and management of malaria in western Kenya. METHODS Cross-sectional active case detection (ACD) of malaria survey was carried out between May and August 2021 in three eco-epidemiologically distinct zones in Kisumu, western Kenya: Kano Plains, Lowland lakeshore and Highland Plateau. The CHVs conducted biweekly ACD of malaria household visits to interview and examine residents for febrile illness. The Community Health Volunteers (CHVs) performance during the ACD of malaria was observed and interviews done using structured questionnaires. RESULTS Of the total 28,800 surveyed, 2597 (9%) had fever and associated malaria symptoms. Eco-epidemiological zones, gender, age group, axillary body temperature, bed net use, travel history, and survey month all had a significant association with malaria febrile illness (p < 0.05). The qualification of the CHV had a significant influence on the quality of their service. The number of health trainings received by the CHVs was significantly related to the correctness of using job aid (χ2 = 6.261, df = 1, p = 0.012) and safety procedures during the ACD activity (χ2 = 4.114, df = 1, p = 0.043). Male CHVs were more likely than female CHVs to correctly refer RDT-negative febrile residents to a health facility for further treatment (OR = 3.94, 95% CI = 1.85-5.44, p < 0.0001). Most of RDT-negative febrile residents who were correctly referred to the health facility came from the clusters with a CHV having 10 years of experience or more (OR = 1.29, 95% CI = 1.05-1.57, p = 0.016). Febrile residents in clusters managed by CHVs with more than 10 years of experience (OR = 1.82, 95% CI = 1.43-2.31, p < 0.0001), who had a secondary education (OR = 1.53, 95% CI = 1.27-1.85, p < 0.0001), and were over the age of 50 (OR = 1.44, 95% CI = 1.18-1.76, p < 0.0001), were more likely to seek malaria treatment in public hospitals. All RDT positive febrile residents were given anti-malarial by the CHVs, and RDT negatives were referred to the nearest health facility for further treatment. CONCLUSIONS The CHV's years of experience, education level, and age had a significant influence on their service quality. Understanding the qualifications of CHVs can assist healthcare systems and policymakers in designing effective interventions that assist CHVs in providing high-quality services to their communities.
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Affiliation(s)
- Wilfred Ouma Otambo
- International Centre of Excellence for Malaria Research, Tom Mboya University, University of California Irvine Joint Lab, Homa Bay, Kenya
| | - Kevin O. Ochwedo
- International Centre of Excellence for Malaria Research, Tom Mboya University, University of California Irvine Joint Lab, Homa Bay, Kenya
| | - Collince J. Omondi
- International Centre of Excellence for Malaria Research, Tom Mboya University, University of California Irvine Joint Lab, Homa Bay, Kenya
| | - Ming-Chieh Lee
- Program in Public Health, University of California Irvine, Irvine, CA USA
| | - Chloe Wang
- Program in Public Health, University of California Irvine, Irvine, CA USA
| | - Harrysone Atieli
- International Centre of Excellence for Malaria Research, Tom Mboya University, University of California Irvine Joint Lab, Homa Bay, Kenya
| | - Andew K. Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guofa Zhou
- Program in Public Health, University of California Irvine, Irvine, CA USA
| | - James Kazura
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH USA
| | - John Githure
- International Centre of Excellence for Malaria Research, Tom Mboya University, University of California Irvine Joint Lab, Homa Bay, Kenya
| | - Guiyun Yan
- Program in Public Health, University of California Irvine, Irvine, CA USA
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Ondeto BM, Wang X, Atieli H, Zhong D, Zhou G, Lee MC, Orondo PW, Ochwedo KO, Omondi CJ, Muriu SM, Odongo DO, Ochanda H, Kazura J, Githeko AK, Yan G. A prospective cohort study of Plasmodium falciparum malaria in three sites of Western Kenya. Parasit Vectors 2022; 15:416. [PMID: 36352453 PMCID: PMC9647947 DOI: 10.1186/s13071-022-05503-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 09/14/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Malaria in western Kenya is currently characterized by sustained high Plasmodial transmission and infection resurgence, despite positive responses in some areas following intensified malaria control interventions since 2006. This study aimed to evaluate long-term changes in malaria transmission profiles and to assess patterns of asymptomatic malaria infections in school children aged 5-15 years at three sites in western Kenya with heterogeneous malaria transmission and simultaneous malaria control interventions. METHODS The study was conducted from 2018 to 2019 and is based on data taken every third year from 2005 to 2014 during a longitudinal parasitological and mosquito adult surveillance and malaria control programme that was initiated in 2002 in the villages of Kombewa, Iguhu, and Marani. Plasmodium spp. infections were determined using microscopy. Mosquito samples were identified to species and host blood meal source and sporozoite infections were assayed using polymerase chain reaction. RESULTS Plasmodium falciparum was the only malaria parasite evaluated during this study (2018-2019). Asymptomatic malaria parasite prevalence in school children decreased in all sites from 2005 to 2008. However, since 2011, parasite prevalence has resurged by > 40% in Kombewa and Marani. Malaria vector densities showed similar reductions from 2005 to 2008 in all sites, rose steadily until 2014, and decreased again. Overall, Kombewa had a higher risk of infection compared to Iguhu (χ2 = 552.52, df = 1, P < 0.0001) and Marani (χ2 = 1127.99, df = 1, P < 0.0001). There was a significant difference in probability of non-infection during malaria episodes (log-rank test, χ2 = 617.59, df = 2, P < 0.0001) in the study sites, with Kombewa having the least median time of non-infection during malaria episodes. Gender bias toward males in infection was observed (χ2 = 27.17, df = 1, P < 0.0001). The annual entomological inoculation rates were 5.12, 3.65, and 0.50 infective bites/person/year at Kombewa, Iguhu, and Marani, respectively, during 2018 to 2019. CONCLUSIONS Malaria prevalence in western Kenya remains high and has resurged in some sites despite continuous intervention efforts. Targeting malaria interventions to those with asymptomatic infections who serve as human reservoirs might decrease malaria transmission and prevent resurgences. Longitudinal monitoring enables detection of changes in parasitological and entomological profiles and provides core baseline data for the evaluation of vector interventions and guidance for future planning of malaria control.
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Affiliation(s)
- Benyl M. Ondeto
- grid.10604.330000 0001 2019 0495Department of Biology, University of Nairobi, Nairobi, 00100 Kenya ,Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300 Kenya
| | - Xiaoming Wang
- grid.266093.80000 0001 0668 7243Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA 92697 USA
| | - Harrysone Atieli
- Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300 Kenya
| | - Daibin Zhong
- grid.266093.80000 0001 0668 7243Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA 92697 USA
| | - Guofa Zhou
- grid.266093.80000 0001 0668 7243Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA 92697 USA
| | - Ming-Chieh Lee
- grid.266093.80000 0001 0668 7243Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA 92697 USA
| | - Pauline Winnie Orondo
- Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300 Kenya ,grid.411943.a0000 0000 9146 7108Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi, 00200 Kenya
| | - Kevin O. Ochwedo
- grid.10604.330000 0001 2019 0495Department of Biology, University of Nairobi, Nairobi, 00100 Kenya ,Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300 Kenya
| | - Collince J. Omondi
- grid.10604.330000 0001 2019 0495Department of Biology, University of Nairobi, Nairobi, 00100 Kenya ,Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300 Kenya
| | - Simon M. Muriu
- grid.449370.d0000 0004 1780 4347Department of Biological Sciences, Pwani University, Kilifi, 80108 Kenya
| | - David O. Odongo
- grid.10604.330000 0001 2019 0495Department of Biology, University of Nairobi, Nairobi, 00100 Kenya
| | - Horace Ochanda
- grid.10604.330000 0001 2019 0495Department of Biology, University of Nairobi, Nairobi, 00100 Kenya
| | - James Kazura
- grid.67105.350000 0001 2164 3847Center for Global Health and Disease, Case Western Reserve University, Cleveland, OH 44106 USA
| | - Andrew K. Githeko
- Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300 Kenya ,grid.33058.3d0000 0001 0155 5938Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, 40100 Kenya
| | - Guiyun Yan
- grid.266093.80000 0001 0668 7243Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA 92697 USA
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9
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Zhou G, Hemming-Schroeder E, Jeang B, Wang X, Zhong D, Lee MC, Li Y, Bradley L, Gobran SR, David RE, Ondeto BM, Orondo P, Atieli H, Githure JI, Githeko AK, Kazura J, Yan G. Irrigation-Induced Environmental Changes Sustain Malaria Transmission and Compromise Intervention Effectiveness. J Infect Dis 2022; 226:1657-1666. [PMID: 36056912 DOI: 10.1093/infdis/jiac361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 09/01/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Irrigated agriculture enhances food security, but it potentially promotes mosquito-borne disease transmission and affects vector intervention effectiveness. This study was conducted in the irrigated and nonirrigated areas of rural Homa Bay and Kisumu Counties, Kenya. METHODS We performed cross-sectional and longitudinal surveys to determine Plasmodium infection prevalence, clinical malaria incidence, molecular force of infection (molFOI), and multiplicity of infection. We examined the impact of irrigation on the effectiveness of the new interventions. RESULTS We found that irrigation was associated with >2-fold higher Plasmodium infection prevalence and 3-fold higher clinical malaria incidence compared to the nonirrigated area. Residents in the irrigated area experienced persistent, low-density parasite infections and higher molFOI. Addition of indoor residual spraying was effective in reducing malaria burden, but the reduction was more pronounced in the nonirrigated area than in the irrigated area. CONCLUSIONS Our findings collectively suggest that irrigation may sustain and enhance Plasmodium transmission and affects intervention effectiveness.
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Affiliation(s)
- Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, USA
| | - Elizabeth Hemming-Schroeder
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, USA.,Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Brook Jeang
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, USA
| | - Xiaoming Wang
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, USA
| | - Daibin Zhong
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, USA
| | - Ming-Chieh Lee
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, USA
| | - Yiji Li
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, USA.,Department of Pathogen Biology, Hainan Medical University, Haikou, China
| | - Lauren Bradley
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, USA
| | - Sabrina R Gobran
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, USA
| | - Randy E David
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, USA
| | - Benyl M Ondeto
- School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Pauline Orondo
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Harrysone Atieli
- School of Public Health and Community Development, Maseno University, Kisumu, Kenya.,International Center of Excellence for Malaria Research, Tom Mboya University College, Homa Bay, Kenya
| | - John I Githure
- International Center of Excellence for Malaria Research, Tom Mboya University College, Homa Bay, Kenya
| | - Andrew K Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - James Kazura
- Center for Global Health and Disease, Case Western Reserve University, Cleveland, Ohio, USA
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, USA
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10
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Ondeto BM, Wang X, Atieli H, Orondo PW, Ochwedo KO, Omondi CJ, Otambo WO, Zhong D, Zhou G, Lee MC, Muriu SM, Odongo DO, Ochanda H, Kazura J, Githeko AK, Yan G. Malaria vector bionomics and transmission in irrigated and non-irrigated sites in western Kenya. Parasitol Res 2022; 121:3529-3545. [PMID: 36203064 DOI: 10.1007/s00436-022-07678-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 09/20/2022] [Indexed: 10/10/2022]
Abstract
Irrigation not only helps to improve food security but also creates numerous water bodies for mosquito production. This study assessed the effect of irrigation on malaria vector bionomics and transmission in a semi-arid site with ongoing malaria vector control program. The effectiveness of CDC light traps in the surveillance of malaria vectors was also evaluated relative to the human landing catches (HLCs) method. Adult mosquitoes were sampled in two study sites representing irrigated and non-irrigated agroecosystems in western Kenya using a variety of trapping methods. The mosquito samples were identified to species and assayed for host blood meal source and Plasmodium spp. sporozoite infection using polymerase chain reaction. Anopheles arabiensis was the dominant malaria vector in the two study sites and occurred in significantly higher densities in irrigated study site compared to the non-irrigated study site. The difference in indoor resting density of An. arabiensis during the dry and wet seasons was not significant. Other species, including An. funestus, An. coustani, and An. pharoensis, were collected. The An. funestus indoor resting density was 0.23 in irrigated study site while almost none of this species was collected in the non-irrigated study site. The human blood index (HBI) for An. arabiensis in the irrigated study site was 3.44% and significantly higher than 0.00% for the non-irrigated study site. In the irrigated study site, the HBI of An. arabiensis was 3.90% and 5.20% indoor and outdoor, respectively. The HBI of An. funestus was 49.43% and significantly higher compared to 3.44% for An. arabiensis in the irrigated study site. The annual entomologic inoculation rate for An. arabiensis in the irrigated study site was 0.41 and 0.30 infective bites/person/year indoor and outdoor, respectively, whereas no transmission was observed in the non-irrigated study site. The CDC light trap performed consistently with HLC in terms of vector density. These findings demonstrate that irrigated agriculture may increase the risk of malaria transmission in irrigated areas compared to the non-irrigated areas and highlight the need to complement the existing malaria vector interventions with novel tools targeting the larvae and both indoor and outdoor biting vector populations.
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Affiliation(s)
- Benyl M Ondeto
- Department of Biology, University of Nairobi, Nairobi, 00100, Kenya. .,Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300, Kenya.
| | - Xiaoming Wang
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Harrysone Atieli
- Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300, Kenya
| | - Pauline Winnie Orondo
- Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300, Kenya.,Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi, 00200, Kenya
| | - Kevin O Ochwedo
- Department of Biology, University of Nairobi, Nairobi, 00100, Kenya.,Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300, Kenya
| | - Collince J Omondi
- Department of Biology, University of Nairobi, Nairobi, 00100, Kenya.,Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300, Kenya
| | - Wilfred O Otambo
- Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300, Kenya.,Department of Zoology, Maseno University, Maseno, Kenya
| | - Daibin Zhong
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Ming-Chieh Lee
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Simon M Muriu
- Department of Biological Sciences, Pwani University, Kilifi, 80108, Kenya
| | - David O Odongo
- Department of Biology, University of Nairobi, Nairobi, 00100, Kenya
| | - Horace Ochanda
- Department of Biology, University of Nairobi, Nairobi, 00100, Kenya
| | - James Kazura
- Center for Global Health and Disease, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Andrew K Githeko
- Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300, Kenya.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, 40100, Kenya
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA.
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11
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Otambo WO, Onyango PO, Ochwedo K, Olumeh J, Onyango SA, Orondo P, Atieli H, Lee MC, Wang C, Zhong D, Githeko A, Zhou G, Githure J, Ouma C, Yan G, Kazura J. Clinical malaria incidence and health seeking pattern in geographically heterogeneous landscape of western Kenya. BMC Infect Dis 2022; 22:768. [PMID: 36192672 PMCID: PMC9528858 DOI: 10.1186/s12879-022-07757-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 09/27/2022] [Indexed: 12/03/2022] Open
Abstract
Background Malaria remains a public health problem in Kenya despite sustained interventions deployed by the government. One of the major impediments to effective malaria control is a lack of accurate diagnosis and effective treatment. This study was conducted to assess clinical malaria incidence and treatment seeking profiles of febrile cases in western Kenya. Methods Active case detection of malaria was carried out in three eco-epidemiologically distinct zones topologically characterized as lakeshore, hillside, and highland plateau in Kisumu County, western Kenya, from March 2020 to March 2021. Community Health Volunteers (CHVs) conducted biweekly visits to residents in their households to interview and examine for febrile illness. A febrile case was defined as an individual having fever (axillary temperature ≥ 37.5 °C) during examination or complaints of fever and other nonspecific malaria related symptoms 1–2 days before examination. Prior to the biweekly malaria testing by the CHVs, the participants' treatment seeking methods were based on their behaviors in response to febrile illness. In suspected malaria cases, finger-prick blood samples were taken and tested for malaria parasites with ultra-sensitive Alere® malaria rapid diagnostic tests (RDT) and subjected to real-time polymerase chain reaction (RT-PCR) for quality control examination. Results Of the total 5838 residents interviewed, 2205 residents had high temperature or reported febrile illness in the previous two days before the visit. Clinical malaria incidence (cases/1000people/month) was highest in the lakeshore zone (24.3), followed by the hillside (18.7) and the highland plateau zone (10.3). Clinical malaria incidence showed significant difference across gender (χ2 = 7.57; df = 2, p = 0.0227) and age group (χ2 = 58.34; df = 4, p < 0.0001). Treatment seeking patterns of malaria febrile cases showed significant difference with doing nothing (48.7%) and purchasing antimalarials from drug shops (38.1%) being the most common health-seeking pattern among the 2205 febrile residents (χ2 = 21.875; df = 4, p < 0.0001). Caregivers of 802 school-aged children aged 5–14 years with fever primarily sought treatment from drug shops (28.9%) and public hospitals (14.0%), with significant lower proportions of children receiving treatment from traditional medication (2.9%) and private hospital (4.4%) (p < 0.0001). There was no significant difference in care givers' treatment seeking patterns for feverish children under the age of five (p = 0.086). Residents with clinical malaria cases in the lakeshore and hillside zones sought treatment primarily from public hospitals (61.9%, 60/97) traditional medication (51.1%, 23/45) respectively (p < 0.0001). However, there was no significant difference in the treatment seeking patterns of highland plateau residents with clinical malaria (p = 0.431).The main factors associated with the decision to seek treatment were the travel distance to the health facility, the severity of the disease, confidence in the treatment, and affordability. Conclusion Clinical malaria incidence remains highest in the Lakeshore (24.3cases/1000 people/month) despite high LLINs coverage (90%). The travel distance to the health facility, severity of disease and affordability were mainly associated with 80% of residents either self-medicating or doing nothing to alleviate their illness. The findings of this study suggest that the Ministry of Health should strengthen community case management of malaria by providing supportive supervision of community health volunteers to advocate for community awareness, early diagnosis, and treatment of malaria. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-022-07757-w.
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Affiliation(s)
- Wilfred Ouma Otambo
- Department of Zoology, Maseno University, Kisumu, Kenya. .,International Centre of Excellence for Malaria Research, Tom Mboya University College-University of California Irvine Joint Lab, Homa Bay, Kenya.
| | | | - Kevin Ochwedo
- International Centre of Excellence for Malaria Research, Tom Mboya University College-University of California Irvine Joint Lab, Homa Bay, Kenya
| | - Julius Olumeh
- School of Natural and Environmental Science, Newcastle University, Newcastle Upon Tyne, UK
| | - Shirley A Onyango
- International Centre of Excellence for Malaria Research, Tom Mboya University College-University of California Irvine Joint Lab, Homa Bay, Kenya
| | - Pauline Orondo
- International Centre of Excellence for Malaria Research, Tom Mboya University College-University of California Irvine Joint Lab, Homa Bay, Kenya
| | - Harrysone Atieli
- International Centre of Excellence for Malaria Research, Tom Mboya University College-University of California Irvine Joint Lab, Homa Bay, Kenya
| | - Ming-Chieh Lee
- Program in Public Health, University of California Irvine, Irvine, CA, USA
| | - Chloe Wang
- Program in Public Health, University of California Irvine, Irvine, CA, USA
| | - Daibin Zhong
- Program in Public Health, University of California Irvine, Irvine, CA, USA
| | - Andrew Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guofa Zhou
- Program in Public Health, University of California Irvine, Irvine, CA, USA
| | - John Githure
- International Centre of Excellence for Malaria Research, Tom Mboya University College-University of California Irvine Joint Lab, Homa Bay, Kenya
| | - Collins Ouma
- Department of Biomedical Sciences and Technology, Maseno University, Kisumu, Kenya
| | - Guiyun Yan
- Program in Public Health, University of California Irvine, Irvine, CA, USA
| | - James Kazura
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
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12
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Otambo WO, Onyango PO, Wang C, Olumeh J, Ondeto BM, Lee MC, Atieli H, Githeko AK, Kazura J, Zhong D, Zhou G, Githure J, Ouma C, Yan G. Influence of landscape heterogeneity on entomological and parasitological indices of malaria in Kisumu, Western Kenya. Parasit Vectors 2022; 15:340. [PMID: 36167549 PMCID: PMC9516797 DOI: 10.1186/s13071-022-05447-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 08/22/2022] [Indexed: 12/04/2022] Open
Abstract
Background Identification and characterization of larval habitats, documentation of Anopheles spp. composition and abundance, and Plasmodium spp. infection burden are critical components of integrated vector management. The present study aimed to investigate the effect of landscape heterogeneity on entomological and parasitological indices of malaria in western Kenya. Methods A cross-sectional entomological and parasitological survey was conducted along an altitudinal transect in three eco-epidemiological zones: lakeshore along the lakeside, hillside, and highland plateau during the wet and dry seasons in 2020 in Kisumu County, Kenya. Larval habitats for Anopheles mosquitoes were identified and characterized. Adult mosquitoes were sampled using pyrethrum spray catches (PSC). Finger prick blood samples were taken from residents and examined for malaria parasites by real-time PCR (RT-PCR). Results Increased risk of Plasmodium falciparum infection was associated with residency in the lakeshore zone, school-age children, rainy season, and no ITNs (χ2 = 41.201, df = 9, P < 0.0001). Similarly, lakeshore zone and the rainy season significantly increased Anopheles spp. abundance. However, house structures such as wall type and whether the eave spaces were closed or open, as well as the use of ITNs, did not affect Anopheles spp. densities in the homes (χ2 = 38.695, df = 7, P < 0.0001). Anopheles funestus (41.8%) and An. arabiensis (29.1%) were the most abundant vectors in all zones. Sporozoite prevalence was 5.6% and 3.2% in the two species respectively. The lakeshore zone had the highest sporozoite prevalence (4.4%, 7/160) and inoculation rates (135.2 infective bites/person/year). High larval densities were significantly associated with lakeshore zone and hillside zones, animal hoof prints and tire truck larval habitats, wetland and pasture land, and the wet season. The larval habitat types differed significantly across the landscape zones and seasonality (χ2 = 1453.044, df = 298, P < 0.0001). Conclusion The empirical evidence on the impact of landscape heterogeneity and seasonality on vector densities, parasite transmission, and Plasmodium infections in humans emphasizes the importance of tailoring specific adaptive environmental management interventions to specific landscape attributes to have a significant impact on transmission reduction. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05447-9.
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Affiliation(s)
- Wilfred Ouma Otambo
- Department of Zoology, Maseno University, Kisumu, Kenya. .,International Centre of Excellence for Malaria Research, Tom Mboya University College-University of California Irvine Joint Lab, Homa Bay, Kenya.
| | | | - Chloe Wang
- Program in Public Health, University of California Irvine, Irvine, CA, USA
| | - Julius Olumeh
- School of Natural and Environmental Science, Newcastle University, Newcastle, UK
| | - Benyl M Ondeto
- International Centre of Excellence for Malaria Research, Tom Mboya University College-University of California Irvine Joint Lab, Homa Bay, Kenya.,Department of Biology, University of Nairobi, Nairobi, Kenya
| | - Ming-Chieh Lee
- Program in Public Health, University of California Irvine, Irvine, CA, USA
| | - Harrysone Atieli
- International Centre of Excellence for Malaria Research, Tom Mboya University College-University of California Irvine Joint Lab, Homa Bay, Kenya
| | - Andrew K Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - James Kazura
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.,Centre for Global Health and Diseases, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Daibin Zhong
- Program in Public Health, University of California Irvine, Irvine, CA, USA
| | - Guofa Zhou
- Program in Public Health, University of California Irvine, Irvine, CA, USA
| | - John Githure
- International Centre of Excellence for Malaria Research, Tom Mboya University College-University of California Irvine Joint Lab, Homa Bay, Kenya
| | - Collins Ouma
- Department of Biomedical Sciences and Technology, Maseno University, Kisumu, Kenya
| | - Guiyun Yan
- Program in Public Health, University of California Irvine, Irvine, CA, USA
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13
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Otambo WO, Omondi CJ, Ochwedo KO, Onyango PO, Atieli H, Lee MC, Wang C, Zhou G, Githeko AK, Githure J, Ouma C, Yan G, Kazura J. Risk associations of submicroscopic malaria infection in lakeshore, plateau and highland areas of Kisumu County in western Kenya. PLoS One 2022; 17:e0268463. [PMID: 35576208 PMCID: PMC9109926 DOI: 10.1371/journal.pone.0268463] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/29/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Persons with submicroscopic malaria infection are a major reservoir of gametocytes that sustain malaria transmission in sub-Saharan Africa. Despite recent decreases in the national malaria burden in Kenya due to vector control interventions, malaria transmission continues to be high in western regions of the country bordering Lake Victoria. The objective of this study was to advance knowledge of the topographical, demographic and behavioral risk factors associated with submicroscopic malaria infection in the Lake Victoria basin in Kisumu County. METHODS Cross-sectional community surveys for malaria infection were undertaken in three eco-epidemiologically distinct zones in Nyakach sub-County, Kisumu. Adjacent regions were topologically characterized as lakeshore, hillside and highland plateau. Surveys were conducted during the 2019 and 2020 wet and dry seasons. Finger prick blood smears and dry blood spots (DBS) on filter paper were collected from 1,777 healthy volunteers for microscopic inspection and real time-PCR (RT-PCR) diagnosis of Plasmodium infection. Persons who were PCR positive but blood smear negative were considered to harbor submicroscopic infections. Topographical, demographic and behavioral risk factors were correlated with community prevalence of submicroscopic infections. RESULTS Out of a total of 1,777 blood samples collected, 14.2% (253/1,777) were diagnosed as submicroscopic infections. Blood smear microscopy and RT-PCR, respectively, detected 3.7% (66/1,777) and 18% (319/1,777) infections. Blood smears results were exclusively positive for P. falciparum, whereas RT-PCR also detected P. malariae and P. ovale mono- and co-infections. Submicroscopic infection prevalence was associated with topographical variation (χ2 = 39.344, df = 2, p<0.0001). The highest prevalence was observed in the lakeshore zone (20.6%, n = 622) followed by the hillside (13.6%, n = 595) and highland plateau zones (7.9%, n = 560). Infection prevalence varied significantly according to season (χ2 = 17.374, df = 3, p<0.0001). The highest prevalence was observed in residents of the lakeshore zone in the 2019 dry season (29.9%, n = 167) and 2020 and 2019 rainy seasons (21.5%, n = 144 and 18.1%, n = 155, respectively). In both the rainy and dry seasons the likelihood of submicroscopic infection was higher in the lakeshore (AOR: 2.71, 95% CI = 1.85-3.95; p<0.0001) and hillside (AOR: 1.74, 95% CI = 1.17-2.61, p = 0.007) than in the highland plateau zones. Residence in the lakeshore zone (p<0.0001), male sex (p = 0.025), school age (p = 0.002), and living in mud houses (p = 0.044) increased the risk of submicroscopic malaria infection. Bed net use (p = 0.112) and occupation (p = 0.116) were not associated with submicroscopic infection prevalence. CONCLUSION Topographic features of the local landscape and seasonality are major correlates of submicroscopic malaria infection in the Lake Victoria area of western Kenya. Diagnostic tests more sensitive than blood smear microscopy will allow for monitoring and targeting geographic sites where additional vector interventions are needed to reduce malaria transmission.
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Affiliation(s)
- Wilfred Ouma Otambo
- Department of Zoology, Maseno University, Kisumu, Kenya
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya
| | - Collince J. Omondi
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya
- Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
| | - Kevin O. Ochwedo
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya
- Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
| | | | - Harrysone Atieli
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya
| | - Ming-Chieh Lee
- Department of Population Health and Disease Prevention, University of California, Irvine, CA, United States of America
| | - Chloe Wang
- Department of Population Health and Disease Prevention, University of California, Irvine, CA, United States of America
| | - Guofa Zhou
- Department of Population Health and Disease Prevention, University of California, Irvine, CA, United States of America
| | - Andrew K. Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - John Githure
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya
| | - Collins Ouma
- Department of Biomedical Sciences and Technology, Maseno University, Kisumu, Kenya
| | - Guiyun Yan
- Department of Population Health and Disease Prevention, University of California, Irvine, CA, United States of America
| | - James Kazura
- Centre for Global Health & Diseases, Case Western University Reserve, Cleveland, Ohio, United States of America
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14
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Otambo WO, Olumeh JO, Ochwedo KO, Magomere EO, Debrah I, Ouma C, Onyango P, Atieli H, Mukabana WR, Wang C, Lee MC, Githeko AK, Zhou G, Githure J, Kazura J, Yan G. Health care provider practices in diagnosis and treatment of malaria in rural communities in Kisumu County, Kenya. Malar J 2022; 21:129. [PMID: 35459178 PMCID: PMC9034626 DOI: 10.1186/s12936-022-04156-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 04/07/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Accurate malaria diagnosis and appropriate treatment at local health facilities are critical to reducing morbidity and human reservoir of infectious gametocytes. The current study assessed the accuracy of malaria diagnosis and treatment practices in three health care facilities in rural western Kenya. METHODS The accuracy of malaria detection and treatment recommended compliance was monitored in two public and one private hospital from November 2019 through March 2020. Blood smears from febrile patients were examined by hospital laboratory technicians and re-examined by an expert microscopists thereafter subjected to real-time polymerase chain reaction (RT-PCR) for quality assurance. In addition, blood smears from patients diagnosed with malaria rapid diagnostic tests (RDT) and presumptively treated with anti-malarial were re-examined by an expert microscopist. RESULTS A total of 1131 febrile outpatients were assessed for slide positivity (936), RDT (126) and presumptive diagnosis (69). The overall positivity rate for Plasmodium falciparum was 28% (257/936). The odds of slide positivity was higher in public hospitals, 30% (186/624, OR:1.44, 95% CI = 1.05-1.98, p < 0.05) than the private hospital 23% (71/312, OR:0.69, 95% CI = 0.51-0.95, p < 0.05). Anti-malarial treatment was dispensed more at public hospitals (95.2%, 177/186) than the private hospital (78.9%, 56/71, p < 0.0001). Inappropriate anti-malarial treatment, i.e. artemether-lumefantrine given to blood smear negative patients was higher at public hospitals (14.6%, 64/438) than the private hospital (7.1%, 17/241) (p = 0.004). RDT was the most sensitive (73.8%, 95% CI = 39.5-57.4) and specific (89.2%, 95% CI = 78.5-95.2) followed by hospital microscopy (sensitivity 47.6%, 95% CI = 38.2-57.1) and specificity (86.7%, 95% CI = 80.8-91.0). Presumptive diagnosis had the lowest sensitivity (25.7%, 95% CI = 13.1-43.6) and specificity (75.0%, 95% CI = 50.6-90.4). RDT had the highest non-treatment of negatives [98.3% (57/58)] while hospital microscopy had the lowest [77.3% (116/150)]. Health facilities misdiagnosis was at 27.9% (77/276). PCR confirmed 5.2% (4/23) of the 77 misdiagnosed cases as false positive and 68.5% (37/54) as false negative. CONCLUSIONS The disparity in malaria diagnosis at health facilities with many slide positives reported as negatives and high presumptive treatment of slide negative cases, necessitates augmenting microscopic with RDTs and calls for Ministry of Health strengthening supportive infrastructure to be in compliance with treatment guidelines of Test, Treat, and Track to improve malaria case management.
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Affiliation(s)
- Wilfred Ouma Otambo
- grid.442486.80000 0001 0744 8172Department of Zoology, Maseno University, Kisumu, Kenya ,International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya
| | - Julius O. Olumeh
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya ,grid.10604.330000 0001 2019 0495Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
| | - Kevin O. Ochwedo
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya ,grid.10604.330000 0001 2019 0495Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
| | - Edwin O. Magomere
- grid.8301.a0000 0001 0431 4443Department of Biochemistry and Molecular Biology, Egerton University, Njoro, Kenya
| | - Isaiah Debrah
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya ,grid.8652.90000 0004 1937 1485West Africa Centre for Cell Biology of Infectious Pathogen, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
| | - Collins Ouma
- grid.442486.80000 0001 0744 8172Department of Biomedical Sciences and Technology, Maseno University, Kisumu, Kenya
| | - Patrick Onyango
- grid.442486.80000 0001 0744 8172Department of Zoology, Maseno University, Kisumu, Kenya
| | - Harrysone Atieli
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya
| | - Wolfgang R. Mukabana
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya ,grid.10604.330000 0001 2019 0495Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
| | - Chloe Wang
- grid.266093.80000 0001 0668 7243Depatment of Population Health and Disease Prevention, University of California, Irvine, CA USA
| | - Ming-Chieh Lee
- grid.266093.80000 0001 0668 7243Depatment of Population Health and Disease Prevention, University of California, Irvine, CA USA
| | - Andrew K. Githeko
- grid.33058.3d0000 0001 0155 5938Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guofa Zhou
- grid.266093.80000 0001 0668 7243Depatment of Population Health and Disease Prevention, University of California, Irvine, CA USA
| | - John Githure
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya
| | - James Kazura
- grid.67105.350000 0001 2164 3847Centre for Global Health and Diseases, Case Western University Reserve, Cleveland, OH USA
| | - Guiyun Yan
- grid.266093.80000 0001 0668 7243Depatment of Population Health and Disease Prevention, University of California, Irvine, CA USA
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15
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Koepfli C, Nguitragool W, de Almeida ACG, Kuehn A, Waltmann A, Kattenberg E, Ome-Kaius M, Rarau P, Obadia T, Kazura J, Monteiro W, Darcy AW, Wini L, Bassat Q, Felger I, Sattabongkot J, Robinson LJ, Lacerda M, Mueller I. Identification of the asymptomatic Plasmodium falciparum and Plasmodium vivax gametocyte reservoir under different transmission intensities. PLoS Negl Trop Dis 2021; 15:e0009672. [PMID: 34449764 PMCID: PMC8428688 DOI: 10.1371/journal.pntd.0009672] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 09/09/2021] [Accepted: 07/21/2021] [Indexed: 11/25/2022] Open
Abstract
Background Understanding epidemiological variables affecting gametocyte carriage and density is essential to design interventions that most effectively reduce malaria human-to-mosquito transmission. Methodology/Principal findings Plasmodium falciparum and P. vivax parasites and gametocytes were quantified by qPCR and RT-qPCR assays using the same methodologies in 5 cross-sectional surveys involving 16,493 individuals in Brazil, Thailand, Papua New Guinea, and Solomon Islands. The proportion of infections with detectable gametocytes per survey ranged from 44–94% for P. falciparum and from 23–72% for P. vivax. Blood-stage parasite density was the most important predictor of the probability to detect gametocytes. In moderate transmission settings (prevalence by qPCR>5%), parasite density decreased with age and the majority of gametocyte carriers were children. In low transmission settings (prevalence<5%), >65% of gametocyte carriers were adults. Per survey, 37–100% of all individuals positive for gametocytes by RT-qPCR were positive by light microscopy for asexual stages or gametocytes (overall: P. falciparum 178/348, P. vivax 235/398). Conclusions/Significance Interventions to reduce human-to-mosquito malaria transmission in moderate-high endemicity settings will have the greatest impact when children are targeted. In contrast, all age groups need to be included in control activities in low endemicity settings to achieve elimination. Detection of infections by light microscopy is a valuable tool to identify asymptomatic blood stage infections that likely contribute most to ongoing transmission at the time of sampling. Plasmodium vivax and Plasmodium falciparum cause the vast majority of all human malaria cases. Across all transmission settings, a large proportion of infections of the two species remain asymptomatic. These infections are not diagnosed and treated by control programs focusing on clinical cases. They can carry gametocytes, the sexual stage of the parasite that establishes infections in mosquitos, thus asymptomatic infections contribute to transmission. In order to determine who is likely to contribute to transmission, gametocyte densities were measured by sensitive molecular methods in afebrile individuals in four countries. The proportion of infections with gametocytes varied greatly among surveys, and was higher in regions that had experienced low transmission for extended periods of time. In moderate-high transmission settings, gametocyte densities were particularly high in children below six years, highlighting the importance that interventions to reduce transmission include this age group. The majority of gametocyte carriers was positive by light microscopy. The comprehensive data on gametocyte carriage presented here lays the foundation for the development of more effective screen and treat activities to reduce malaria transmission.
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Affiliation(s)
- Cristian Koepfli
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
- University of Notre Dame, Eck Institute for Global Health, Department of Biological Sciences, Notre Dame, Indiana, United States of America
- * E-mail:
| | - Wang Nguitragool
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Anne Cristine Gomes de Almeida
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil
- Universidade do Estado do Amazonas, Manaus, Brazil
| | - Andrea Kuehn
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
| | - Andreea Waltmann
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Eline Kattenberg
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, Australia
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Maria Ome-Kaius
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Patricia Rarau
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Thomas Obadia
- Hub de Bioinformatique et Biostatistique, Département Biologie Computationnelle, Institut Pasteur, Paris, France
- Unité Malaria: parasites et Hôtes, Département Parasites et Insectes Vecteurs, Institut Pasteur, Paris, France
| | - James Kazura
- Centre for Global Health & Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Wuelton Monteiro
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil
- Universidade do Estado do Amazonas, Manaus, Brazil
| | - Andrew W. Darcy
- National Health Training and Research Institute, Ministry of Health, Honiara, Solomon Islands
| | - Lyndes Wini
- Vector Borne Diseases Program, Ministry of Health, Honiara, Solomon Islands
| | - Quique Bassat
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
- ICREA, Barcelona, Spain
- Pediatric Infectious Diseases Unit, Pediatrics Department, Hospital Sant Joan de Déu (University of Barcelona), Barcelona, Spain
- Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Ingrid Felger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Leanne J. Robinson
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, Australia
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Marcus Lacerda
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil
| | - Ivo Mueller
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
- Unité Malaria: parasites et Hôtes, Département Parasites et Insectes Vecteurs, Institut Pasteur, Paris, France
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16
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Lautu-Gumal D, Razook Z, Koleala T, Nate E, McEwen S, Timbi D, Hetzel MW, Lavu E, Tefuarani N, Makita L, Kazura J, Mueller I, Pomat W, Laman M, Robinson LJ, Barry AE. Surveillance of molecular markers of Plasmodium falciparum artemisinin resistance (kelch13 mutations) in Papua New Guinea between 2016 and 2018. Int J Parasitol Drugs Drug Resist 2021; 16:188-193. [PMID: 34271323 PMCID: PMC8286961 DOI: 10.1016/j.ijpddr.2021.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/22/2021] [Accepted: 06/25/2021] [Indexed: 11/28/2022]
Abstract
Plasmodium falciparum resistance to artemisinin-based combination therapy (ACT) is a global threat to malaria control and elimination efforts. Mutations in the P. falciparum kelch13 gene (Pfk13) that are associated with delayed parasite clearance have emerged on the Thai-Cambodian border since 2008. There is growing evidence of widespread Pfk13 mutations throughout South-East Asia and they have independently emerged in other endemic regions. In Papua New Guinea (PNG), Pfk13 “C580Y” mutant parasites with reduced in vitro sensitivity to artemisinin have been isolated in Wewak, a port town in East Sepik Province. However, the extent of any local spread of these mutant parasites in other parts of PNG is unknown. We investigated the prevalence of Pfk13 mutations in multiple malaria-endemic regions of PNG. P. falciparum isolates (n = 1152) collected between 2016 and 2018 and assessed for Pfk13 variation by sequencing. Of 663 high quality Pfk13 sequences a total of five variants were identified. They included C580Y, a mutation at a previously documented polymorphic locus: N499K, and three previously undescribed mutations: R471C, K586E and Y635C. All variants were found in single isolates, indicating that these Pfk13 mutations were rare in the areas surveyed. Notably, C580Y was absent from Maprik district, which neighbours Wewak where C580Y mutant parasites were previously identified. The single C580Y isolate was found in the port town of Lae, Morobe Province, a potential entry site for the importation of drug resistant parasites into PNG. Although sample size in this location was small (n = 5), our identification of a C580Y mutant in this second location is concerning, highlighting the urgent need for further surveillance in Lae. Other Pfk13 mutants were rare in PNG between 2016 and 2018. Continued surveillance for molecular markers of drug resistance is critically important to inform malaria control in PNG.
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Affiliation(s)
- Dulcie Lautu-Gumal
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia; Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Madang Province, Papua New Guinea; Life Sciences Discipline, Burnet Institute, Melbourne, Victoria, Australia.
| | - Zahra Razook
- Life Sciences Discipline, Burnet Institute, Melbourne, Victoria, Australia; Institute for Mental and Physical Health and Clinical Translation (IMPACT), School of Medicine, Deakin University, Geelong, Victoria, Australia
| | - Tamarah Koleala
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Madang Province, Papua New Guinea
| | - Elma Nate
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Madang Province, Papua New Guinea
| | - Samuel McEwen
- Life Sciences Discipline, Burnet Institute, Melbourne, Victoria, Australia
| | - Diana Timbi
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Madang Province, Papua New Guinea
| | - Manuel W Hetzel
- Health Interventions Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Evelyn Lavu
- Papua New Guinea Central Public Health Laboratories, Port Moresby, National Capital District, Papua New Guinea
| | - Nakapi Tefuarani
- School of Medicine & Health Sciences, University of Papua New Guinea, Port Moresby, National Capital District, Papua New Guinea
| | - Leo Makita
- Papua New Guinea National Department of Health, Port Moresby, National Capital District, Papua New Guinea
| | - James Kazura
- Centre for Global Health Diseases, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Ivo Mueller
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia; Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - William Pomat
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Madang Province, Papua New Guinea
| | - Moses Laman
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Madang Province, Papua New Guinea
| | - Leanne J Robinson
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia; Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Madang Province, Papua New Guinea; Life Sciences Discipline, Burnet Institute, Melbourne, Victoria, Australia; School of Preventative Medicine and Public Health, Monash University, Melbourne, Victoria, Australia
| | - Alyssa E Barry
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia; Life Sciences Discipline, Burnet Institute, Melbourne, Victoria, Australia; Institute for Mental and Physical Health and Clinical Translation (IMPACT), School of Medicine, Deakin University, Geelong, Victoria, Australia
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17
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Zhou G, Zhong D, Lee MC, Wang X, Atieli HE, Githure JI, Githeko AK, Kazura J, Yan G. Multi-Indicator and Multistep Assessment of Malaria Transmission Risks in Western Kenya. Am J Trop Med Hyg 2021; 104:1359-1370. [PMID: 33556042 DOI: 10.4269/ajtmh.20-1211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 12/24/2020] [Indexed: 11/07/2022] Open
Abstract
Malaria risk factor assessment is a critical step in determining cost-effective intervention strategies and operational plans in a regional setting. We develop a multi-indicator multistep approach to model the malaria risks at the population level in western Kenya. We used a combination of cross-sectional seasonal malaria infection prevalence, vector density, and cohort surveillance of malaria incidence at the village level to classify villages into malaria risk groups through unsupervised classification. Generalized boosted multinomial logistics regression analysis was performed to determine village-level risk factors using environmental, biological, socioeconomic, and climatic features. Thirty-six villages in western Kenya were first classified into two to five operational groups based on different combinations of malaria risk indicators. Risk assessment indicated that altitude accounted for 45-65% of all importance value relative to all other factors; all other variable importance values were < 6% in all models. After adjusting by altitude, villages were classified into three groups within distinct geographic areas regardless of the combination of risk indicators. Risk analysis based on altitude-adjusted classification indicated that factors related to larval habitat abundance accounted for 63% of all importance value, followed by geographic features related to the ponding effect (17%), vegetation cover or greenness (15%), and the number of bed nets combined with February temperature (5%). These results suggest that altitude is the intrinsic factor in determining malaria transmission risk in western Kenya. Malaria vector larval habitat management, such as habitat reduction and larviciding, may be an important supplement to the current first-line vector control tools in the study area.
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Affiliation(s)
- Guofa Zhou
- 1Program in Public Health, University of California, Irvine, California
| | - Daibin Zhong
- 1Program in Public Health, University of California, Irvine, California
| | - Ming-Chieh Lee
- 1Program in Public Health, University of California, Irvine, California
| | - Xiaoming Wang
- 1Program in Public Health, University of California, Irvine, California
| | - Harrysone E Atieli
- 2School of Public Health and Community Development, Maseno University, Kisumu, Kenya
| | - John I Githure
- 3International Center of Excellence in Malaria Research, Tom Mboya University College, Homabay, Kenya
| | - Andrew K Githeko
- 4Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - James Kazura
- 5Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Guiyun Yan
- 1Program in Public Health, University of California, Irvine, California
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18
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Mazhari R, Brewster J, Fong R, Bourke C, Liu ZSJ, Takashima E, Tsuboi T, Tham WH, Harbers M, Chitnis C, Healer J, Ome-Kaius M, Sattabongkot J, Kazura J, Robinson LJ, King C, Mueller I, Longley RJ. A comparison of non-magnetic and magnetic beads for measuring IgG antibodies against Plasmodium vivax antigens in a multiplexed bead-based assay using Luminex technology (Bio-Plex 200 or MAGPIX). PLoS One 2020; 15:e0238010. [PMID: 33275613 PMCID: PMC7717507 DOI: 10.1371/journal.pone.0238010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 11/17/2020] [Indexed: 11/19/2022] Open
Abstract
Multiplexed bead-based assays that use Luminex® xMAP® technology have become popular for measuring antibodies against proteins of interest in many fields, including malaria and more recently SARS-CoV-2/COVID-19. There are currently two formats that are widely used: non-magnetic beads or magnetic beads. Data are lacking regarding the comparability of results obtained using these two types of beads, and for assays run on different instruments. Whilst non-magnetic beads can only be run on flow-based instruments (such as the Luminex® 100/200™ or Bio-Plex® 200), magnetic beads can be run on both these and the newer MAGPIX® instruments. In this study we utilized a panel of purified recombinant Plasmodium vivax proteins and samples from malaria-endemic areas to measure P. vivax-specific IgG responses using different combinations of beads and instruments. We directly compared: i) non-magnetic versus magnetic beads run on a Bio-Plex® 200, ii) magnetic beads run on the Bio-Plex® 200 versus MAGPIX® and iii) non-magnetic beads run on a Bio-Plex® 200 versus magnetic beads run on the MAGPIX®. We also performed an external comparison of our optimized assay. We observed that IgG antibody responses, measured against our panel of P. vivax proteins, were moderately-strongly correlated in all three of our comparisons (pearson r>0.5 for 18/19 proteins), however higher amounts of protein were required for coupling to magnetic beads. Our external comparison indicated that results generated in different laboratories using the same coupled beads are also highly comparable (pearson r>0.7), particularly if a reference standard curve is used.
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Affiliation(s)
- Ramin Mazhari
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Jessica Brewster
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Rich Fong
- Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Caitlin Bourke
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Zoe S. J. Liu
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Wai-Hong Tham
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Matthias Harbers
- CellFree Sciences Co., Ltd., Yokohama, Japan
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Chetan Chitnis
- Department of Parasites & Insect Vectors, Malaria Parasite Biology and Vaccines, Institut Pasteur, Paris, France
| | - Julie Healer
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Maria Ome-Kaius
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Vector Borne Diseases Unit, PNG Institute of Medical Research, Madang, Papua New Guinea
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - James Kazura
- Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Leanne J. Robinson
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
- Vector Borne Diseases Unit, PNG Institute of Medical Research, Madang, Papua New Guinea
- Burnet Institute, Melbourne, Australia
| | - Christopher King
- Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Ivo Mueller
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
- Department of Parasites & Insect Vectors, Malaria Parasites & Hosts Unit, Institut Pasteur, Paris, France
| | - Rhea J. Longley
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
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19
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Kattenberg JH, Razook Z, Keo R, Koepfli C, Jennison C, Lautu-Gumal D, Fola AA, Ome-Kaius M, Barnadas C, Siba P, Felger I, Kazura J, Mueller I, Robinson LJ, Barry AE. Monitoring Plasmodium falciparum and Plasmodium vivax using microsatellite markers indicates limited changes in population structure after substantial transmission decline in Papua New Guinea. Mol Ecol 2020; 29:4525-4541. [PMID: 32985031 PMCID: PMC10008436 DOI: 10.1111/mec.15654] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 07/27/2020] [Indexed: 02/01/2023]
Abstract
Monitoring the genetic structure of pathogen populations may be an economical and sensitive approach to quantify the impact of control on transmission dynamics, highlighting the need for a better understanding of changes in population genetic parameters as transmission declines. Here we describe the first population genetic analysis of two major human malaria parasites, Plasmodium falciparum (Pf) and Plasmodium vivax (Pv), following nationwide distribution of long-lasting insecticide-treated nets (LLINs) in Papua New Guinea (PNG). Parasite isolates from pre- (2005-2006) and post-LLIN (2010-2014) were genotyped using microsatellite markers. Despite parasite prevalence declining substantially (East Sepik Province: Pf = 54.9%-8.5%, Pv = 35.7%-5.6%, Madang Province: Pf = 38.0%-9.0%, Pv: 31.8%-19.7%), genetically diverse and intermixing parasite populations remained. Pf diversity declined modestly post-LLIN relative to pre-LLIN (East Sepik: Rs = 7.1-6.4, HE = 0.77-0.71; Madang: Rs = 8.2-6.1, HE = 0.79-0.71). Unexpectedly, population structure present in pre-LLIN populations was lost post-LLIN, suggesting that more frequent human movement between provinces may have contributed to higher gene flow. Pv prevalence initially declined but increased again in one province, yet diversity remained high throughout the study period (East Sepik: Rs = 11.4-9.3, HE = 0.83-0.80; Madang: Rs = 12.2-14.5, HE = 0.85-0.88). Although genetic differentiation values increased between provinces over time, no significant population structure was observed at any time point. For both species, a decline in multiple infections and increasing clonal transmission and significant multilocus linkage disequilibrium post-LLIN were positive indicators of impact on the parasite population using microsatellite markers. These parameters may be useful adjuncts to traditional epidemiological tools in the early stages of transmission reduction.
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Affiliation(s)
- Johanna Helena Kattenberg
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Yagaum, Papua New Guinea
| | - Zahra Razook
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
| | - Raksmei Keo
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
| | - Cristian Koepfli
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Charlie Jennison
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Dulcie Lautu-Gumal
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Yagaum, Papua New Guinea.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Abebe A Fola
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Maria Ome-Kaius
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Yagaum, Papua New Guinea.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Céline Barnadas
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Yagaum, Papua New Guinea.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Peter Siba
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Ingrid Felger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - James Kazura
- Centre for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - Ivo Mueller
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia.,Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - Leanne J Robinson
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Yagaum, Papua New Guinea.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia.,Disease Elimination, Burnet Institute, Melbourne, VIC, Australia
| | - Alyssa E Barry
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
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20
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Fola AA, Kattenberg E, Razook Z, Lautu-Gumal D, Lee S, Mehra S, Bahlo M, Kazura J, Robinson LJ, Laman M, Mueller I, Barry AE. SNP barcodes provide higher resolution than microsatellite markers to measure Plasmodium vivax population genetics. Malar J 2020; 19:375. [PMID: 33081815 PMCID: PMC7576724 DOI: 10.1186/s12936-020-03440-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 10/03/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Genomic surveillance of malaria parasite populations has the potential to inform control strategies and to monitor the impact of interventions. Barcodes comprising large numbers of single nucleotide polymorphism (SNP) markers are accurate and efficient genotyping tools, however may need to be tailored to specific malaria transmission settings, since 'universal' barcodes can lack resolution at the local scale. A SNP barcode was developed that captures the diversity and structure of Plasmodium vivax populations of Papua New Guinea (PNG) for research and surveillance. METHODS Using 20 high-quality P. vivax genome sequences from PNG, a total of 178 evenly spaced neutral SNPs were selected for development of an amplicon sequencing assay combining a series of multiplex PCRs and sequencing on the Illumina MiSeq platform. For initial testing, 20 SNPs were amplified in a small number of mono- and polyclonal P. vivax infections. The full barcode was then validated by genotyping and population genetic analyses of 94 P. vivax isolates collected between 2012 and 2014 from four distinct catchment areas on the highly endemic north coast of PNG. Diversity and population structure determined from the SNP barcode data was then benchmarked against that of ten microsatellite markers used in previous population genetics studies. RESULTS From a total of 28,934,460 reads generated from the MiSeq Illumina run, 87% mapped to the PvSalI reference genome with deep coverage (median = 563, range 56-7586) per locus across genotyped samples. Of 178 SNPs assayed, 146 produced high-quality genotypes (minimum coverage = 56X) in more than 85% of P. vivax isolates. No amplification bias was introduced due to either polyclonal infection or whole genome amplification (WGA) of samples before genotyping. Compared to the microsatellite panels, the SNP barcode revealed greater variability in genetic diversity between populations and geographical population structure. The SNP barcode also enabled assignment of genotypes according to their geographic origins with a significant association between genetic distance and geographic distance at the sub-provincial level. CONCLUSIONS High-throughput SNP barcoding can be used to map variation of malaria transmission dynamics at sub-national resolution. The low cost per sample and genotyping strategy makes the transfer of this technology to field settings highly feasible.
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Affiliation(s)
- Abebe A Fola
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Eline Kattenberg
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
- Malariology Unit, Institute of Tropical Medicine, Antwerp, Belgium
| | - Zahra Razook
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
- IMPACT Institute for Innovation in Mental and Physical Health and Clinical Translation, Deakin University, 75 Pigdons Road, Waurn Ponds, Geelong, VIC, 3216, Australia
| | - Dulcie Lautu-Gumal
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
- Disease Elimination Program, Burnet Institute, Melbourne, VIC, Australia
- IMPACT Institute for Innovation in Mental and Physical Health and Clinical Translation, Deakin University, 75 Pigdons Road, Waurn Ponds, Geelong, VIC, 3216, Australia
| | - Stuart Lee
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
| | - Somya Mehra
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
- Disease Elimination Program, Burnet Institute, Melbourne, VIC, Australia
- IMPACT Institute for Innovation in Mental and Physical Health and Clinical Translation, Deakin University, 75 Pigdons Road, Waurn Ponds, Geelong, VIC, 3216, Australia
| | - Melanie Bahlo
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - James Kazura
- Disease Elimination Program, Burnet Institute, Melbourne, VIC, Australia
- Centre for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, USA
| | - Leanne J Robinson
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
- Disease Elimination Program, Burnet Institute, Melbourne, VIC, Australia
| | - Moses Laman
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Ivo Mueller
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
- Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - Alyssa E Barry
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia.
- Disease Elimination Program, Burnet Institute, Melbourne, VIC, Australia.
- IMPACT Institute for Innovation in Mental and Physical Health and Clinical Translation, Deakin University, 75 Pigdons Road, Waurn Ponds, Geelong, VIC, 3216, Australia.
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Longley RJ, White MT, Takashima E, Brewster J, Morita M, Harbers M, Obadia T, Robinson LJ, Matsuura F, Liu ZSJ, Li-Wai-Suen CSN, Tham WH, Healer J, Huon C, Chitnis CE, Nguitragool W, Monteiro W, Proietti C, Doolan DL, Siqueira AM, Ding XC, Gonzalez IJ, Kazura J, Lacerda M, Sattabongkot J, Tsuboi T, Mueller I. Development and validation of serological markers for detecting recent Plasmodium vivax infection. Nat Med 2020; 26:741-749. [DOI: 10.1038/s41591-020-0841-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 03/18/2020] [Indexed: 11/09/2022]
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Affiliation(s)
- Rosemary Rochford
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - James Kazura
- Center for Global Health & Diseases, Case Western Reserve University, Cleveland, Ohio
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Quah YW, Waltmann A, Karl S, White MT, Vahi V, Darcy A, Pitakaka F, Whittaker M, Tisch DJ, Barry A, Barnadas C, Kazura J, Mueller I. Molecular epidemiology of residual Plasmodium vivax transmission in a paediatric cohort in Solomon Islands. Malar J 2019; 18:106. [PMID: 30922304 PMCID: PMC6437916 DOI: 10.1186/s12936-019-2727-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 03/14/2019] [Indexed: 01/03/2023] Open
Abstract
Background Following the scale-up of intervention efforts, malaria burden has decreased dramatically in Solomon Islands (SI). Submicroscopic and asymptomatic Plasmodium vivax infections are now the major challenge for malaria elimination in this country. Since children have higher risk of contracting malaria, this study investigated the dynamics of Plasmodium spp. infections among children including the associated risk factors of residual P. vivax burden. Methods An observational cohort study was conducted among 860 children aged 0.5–12 years in Ngella (Central Islands Province, SI). Children were monitored by active and passive surveillances for Plasmodium spp. infections and illness. Parasites were detected by quantitative real-time PCR (qPCR) and genotyped. Comprehensive statistical analyses of P. vivax infection prevalence, molecular force of blood stage infection (molFOB) and infection density were conducted. Results Plasmodium vivax infections were common (overall prevalence: 11.9%), whereas Plasmodium falciparum infections were rare (0.3%) but persistent. Although children acquire an average of 1.1 genetically distinct P. vivax blood-stage infections per year, there was significant geographic heterogeneity in the risks of P. vivax infections across Ngella (prevalence: 1.2–47.4%, p < 0.01; molFOB: 0.05–4.6/year, p < 0.01). Malaria incidence was low (IR: 0.05 episodes/year-at-risk). Age and measures of high exposure were the key risk factors for P. vivax infections and disease. Malaria incidence and infection density decreased with age, indicating significant acquisition of immunity. G6PD deficient children (10.8%) that did not receive primaquine treatment had a significantly higher prevalence (aOR: 1.77, p = 0.01) and increased risk of acquiring new bloodstage infections (molFOB aIRR: 1.51, p = 0.03), underscoring the importance of anti-relapse treatment. Conclusion Residual malaria transmission in Ngella exhibits strong heterogeneity and is characterized by a high proportion of submicroscopic and asymptomatic P. vivax infections, alongside sporadic P. falciparum infections. Implementing an appropriate primaquine treatment policy to prevent P. vivax relapses and specific targeting of control interventions to high risk areas will be required to accelerate ongoing control and elimination activities. Electronic supplementary material The online version of this article (10.1186/s12936-019-2727-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yi Wan Quah
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Andreea Waltmann
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Stephan Karl
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Michael T White
- Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - Ventis Vahi
- National Health Training & Research Institute, Ministry of Health, Honiara, Solomon Islands
| | - Andrew Darcy
- National Health Training & Research Institute, Ministry of Health, Honiara, Solomon Islands
| | - Freda Pitakaka
- National Health Training & Research Institute, Ministry of Health, Honiara, Solomon Islands
| | - Maxine Whittaker
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | | | - Alyssa Barry
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Celine Barnadas
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - James Kazura
- Case Western Reserve University, Cleveland, OH, USA
| | - Ivo Mueller
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia. .,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia. .,Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France.
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Yeo KT, Embury P, Anderson T, Mungai P, Malhotra I, King C, Kazura J, Dent A. HIV, Cytomegalovirus, and Malaria Infections during Pregnancy Lead to Inflammation and Shifts in Memory B Cell Subsets in Kenyan Neonates. J Immunol 2019; 202:1465-1478. [PMID: 30674575 PMCID: PMC6379806 DOI: 10.4049/jimmunol.1801024] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 12/17/2018] [Indexed: 11/19/2022]
Abstract
Infections during pregnancy can expose the fetus to microbial Ags, leading to inflammation that affects B cell development. Prenatal fetal immune priming may have an important role in infant acquisition of pathogen-specific immunity. We examined plasma proinflammatory biomarkers, the proportions of various B cell subsets, and fetal priming to tetanus vaccination in cord blood from human United States and Kenyan neonates. United States neonates had no identified prenatal infectious exposures, whereas Kenyan neonates examined had congenital CMV or mothers with prenatal HIV or Plasmodium falciparum or no identified infectious exposures. Kenyan neonates had higher levels of IP-10, TNF-α, CRP, sCD14, and BAFF than United States neonates. Among the Kenyan groups, neonates with prenatal infections/infectious exposures had higher levels of cord blood IFN-γ, IL-7, sTNFR1, and sTNFR2 compared with neonates with no infectious exposures. Kenyan neonates had greater proportions of activated memory B cells (MBC) compared with United States neonates. Among the Kenyan groups, HIV-exposed neonates had greater proportions of atypical MBC compared with the other groups. Although HIV-exposed neonates had altered MBC subset distributions, detection of tetanus-specific MBC from cord blood, indicative of fetal priming with tetanus vaccine given to pregnant women, was comparable in HIV-exposed and non-HIV-exposed neonates. These results indicate that the presence of infections during pregnancy induces fetal immune activation with inflammation and increased activated MBC frequencies in neonates. The immunologic significance and long-term health consequences of these differences warrant further investigation.
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Affiliation(s)
- Kee Thai Yeo
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH 44106
- Department of Pediatrics, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, OH 44106; and
| | - Paula Embury
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH 44106
| | - Timothy Anderson
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH 44106
| | - Peter Mungai
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH 44106
- Division of Vector Borne and Neglected Tropical Diseases, Ministry of Public Health and Sanitation, Nairobi 00200, Kenya
| | - Indu Malhotra
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH 44106
| | - Christopher King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH 44106
| | - James Kazura
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH 44106
| | - Arlene Dent
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH 44106;
- Department of Pediatrics, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, OH 44106; and
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Taffese HS, Hemming-Schroeder E, Koepfli C, Tesfaye G, Lee MC, Kazura J, Yan GY, Zhou GF. Malaria epidemiology and interventions in Ethiopia from 2001 to 2016. Infect Dis Poverty 2018; 7:103. [PMID: 30392470 PMCID: PMC6217769 DOI: 10.1186/s40249-018-0487-3] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 09/27/2018] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Ethiopia is one of the African countries where Plasmodium falciparum and P. vivax co-exist. Monitoring and evaluation of current malaria transmission status is an important component of malaria control as it is a measure of the success of ongoing interventions and guides the planning of future control and elimination efforts. MAIN TEXT We evaluated changes in malaria control policy in Ethiopia, and reviewed dynamics of country-wide confirmed and clinical malaria cases by Plasmodium species and reported deaths for all ages and less than five years from 2001 to 2016. Districts level annual parasite incidence was analysed to characterize the malaria transmission stratification as implemented by the Ministry of Health. We found that Ethiopia has experienced major changes from 2003 to 2005 and subsequent adjustment in malaria diagnosis, treatment and vector control policy. Malaria interventions have been intensified represented by the increased insecticide treated net (ITN) and indoor residual spraying (IRS) coverage, improved health services and improved malaria diagnosis. However, countrywide ITN and IRS coverages were low, with 64% ITN coverage in 2016 and IRS coverage of 92.5% in 2016 and only implemented in epidemic-prone areas of > 2500 m elevation. Clinical malaria incidence rate dropped from an average of 43.1 cases per 1000 population annually between 2001 and 2010 to 29.0 cases per 1000 population annually between 2011 and 2016. Malaria deaths decreased from 2.1 deaths per 100 000 people annually between 2001 and 2010 to 1.1 deaths per 100 000 people annually between 2011 to 2016. There was shrinkage in the malaria transmission map and high transmission is limited mainly to the western international border area. Proportion of P. falciparum malaria remained nearly unchanged from 2000 to 2016 indicating further efforts are needed to suppress transmission. CONCLUSIONS Malaria morbidity and mortality have been significantly reduced in Ethiopia since 2001, however, malaria case incidence is still high, and there were major gaps between ITN ownership and compliance in malarious areas. Additional efforts are needed to target the high transmission area of western Ethiopia to sustain the achievements made to date.
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Affiliation(s)
- Hiwot S Taffese
- National Malaria Program, Federal Ministry of Health, Addis Ababa, Ethiopia
| | | | - Cristian Koepfli
- Program in Public Health, University of California, Irvine, CA, 92697, USA
| | - Gezahegn Tesfaye
- National Malaria Program, Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Ming-Chieh Lee
- Program in Public Health, University of California, Irvine, CA, 92697, USA
| | - James Kazura
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - Gui-Yun Yan
- Program in Public Health, University of California, Irvine, CA, 92697, USA
| | - Guo-Fa Zhou
- Program in Public Health, University of California, Irvine, CA, 92697, USA.
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Dobbs K, Embury P, Vulule J, Odada P, Rosa B, Mitreva M, Kazura J, Dent A. Primed Innate Immune Responses in Monocytes from Kenyan Children with Uncomplicated Falciparum Malaria. Open Forum Infect Dis 2017. [DOI: 10.1093/ofid/ofx163.461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Guo S, He L, Tisch DJ, Kazura J, Mharakurwa S, Mahanta J, Herrera S, Wang B, Cui L. Pilot testing of dipsticks as point-of-care assays for rapid diagnosis of poor-quality artemisinin drugs in endemic settings. Trop Med Health 2016; 44:15. [PMID: 27433134 PMCID: PMC4940968 DOI: 10.1186/s41182-016-0015-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 04/15/2016] [Indexed: 12/03/2022] Open
Abstract
Background Good-quality artemisinin drugs are essential for malaria treatment, but increasing prevalence of poor-quality artemisinin drugs in many endemic countries hinders effective management of malaria cases. Methods To develop a point-of-care assay for rapid identification of counterfeit and substandard artemisinin drugs for resource-limited areas, we used specific monoclonal antibodies against artesunate and artemether, and developed prototypes of lateral flow dipstick assays. In this pilot test, we evaluated the feasibility of these dipsticks under different endemic settings and their performance in the hands of untrained personnel. Results The results showed that the dipstick tests can be successfully performed by different investigators with the included instruction sheet. None of the artemether and artesunate drugs collected from public pharmacies in different endemic countries failed the test. Conclusion It is possible that the simple dipstick assays, with future optimization of test conditions and sensitivity, can be used as a qualitative and semi-quantitative assay for rapid screening of counterfeit artemisinin drugs in endemic settings.
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Affiliation(s)
- Suqin Guo
- College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| | - Lishan He
- College of Agronomy and Biotechnology, China Agricultural University, Beijing, China.,Present address: College of Agronomy, Guangxi University, 530004 Nanning, China
| | - Daniel J Tisch
- Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH USA
| | - James Kazura
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH USA
| | - Sungano Mharakurwa
- Malaria Research Department, Macha Research Trust, Johns Hopkins Malaria Research Institute, Choma, Zambia
| | - Jagadish Mahanta
- Regional Medical Research Centre (NE), Dibrugarh, 786001 Assam India
| | - Sócrates Herrera
- Caucaseco Scientific Research Center and Malaria Vaccine and Drug Development Center, Cali, Colombia
| | - Baomin Wang
- College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, PA 16802 USA
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Babakhanyan A, Ekali GL, Dent A, Kazura J, Nguasong JT, Fodjo BAY, Yuosembom EK, Esemu LF, Taylor DW, Leke RGF. Maternal Human Immunodeficiency Virus-Associated Hypergammaglobulinemia Reduces Transplacental Transfer of Immunoglobulin G to Plasmodium falciparum Antigens in Cameroonian Neonates. Open Forum Infect Dis 2016; 3:ofw092. [PMID: 28487863 PMCID: PMC4943556 DOI: 10.1093/ofid/ofw092] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 05/06/2016] [Indexed: 11/14/2022] Open
Abstract
Background. Human immunodeficiency virus (HIV) infection reduces placental transfer of antibodies from mother to the fetus for many antigens; however, conflicting data exist for transfer of immunoglobulin G (IgG) to malarial antigens. The mechanism(s) underlying reduced placental transfer is unknown. Methods. Levels of maternal and cord total IgG, IgG subclasses, and cord-to-mother ratios (CMRs) were measured in 107 mother-cord pairs to 3 malarial antigens: circumsporozoite protein (CSP), apical membrane antigen 1 (AMA-1), merozoite surface protein 1 (MSP-1), and tetanus toxoid C-fragment (TTc). Results. Immunoglobulin G levels to CSP and TTc were lower in HIV+ mothers, and cord IgG to CSP, MSP-1, and TTc were significantly lower in neonates born to HIV+ mothers (all P values <.05). The prevalence of mothers with hypergammaglobulinemia was significantly higher among HIV+ women (68%) compared with HIV− mothers (8%) (P < .0001). Maternal hypergammaglobulinemia was associated with reduction in transplacental transfer of antibodies to CSP (P = .03), MSP-1 (P = .004), and TTc (P = .012), and CMRs <1 were found for MSP-1 (odds ratio [OR] = 6.5), TTc (OR = 4.95), and IgG1 to CSP (OR = 3.75, P = .025) in statistical models adjusted for maternal IgG. Conclusions. Data confirmed that HIV infections are associated with lower cord antibody levels to malarial antigens and that hypergammaglobulinemia may contribute to reduced antibody transfer.
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Affiliation(s)
- Anna Babakhanyan
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, University of Hawaii at Manoa, John A. Burns School of Medicine, Honolulu
| | - Gabriel Loni Ekali
- Biotechnology Center, Faculty of Medicine and Biomedical Research, University of Yaoundé 1, Cameroon
| | - Arlene Dent
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - James Kazura
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - John Tamo Nguasong
- Biotechnology Center, Faculty of Medicine and Biomedical Research, University of Yaoundé 1, Cameroon
| | | | - Emile Keming Yuosembom
- Biotechnology Center, Faculty of Medicine and Biomedical Research, University of Yaoundé 1, Cameroon
| | - Livo Forgu Esemu
- Biotechnology Center, Faculty of Medicine and Biomedical Research, University of Yaoundé 1, Cameroon
| | - Diane Wallace Taylor
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, University of Hawaii at Manoa, John A. Burns School of Medicine, Honolulu
| | - Rose Gana Fomban Leke
- Biotechnology Center, Faculty of Medicine and Biomedical Research, University of Yaoundé 1, Cameroon
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Dent A, Yeo KT, Embury P, Anderson T, Mungai P, Holding P, Malhotra I, King C, Kazura J. Chronic infectious exposures during pregnancy shift the distribution of cord blood fetal memory B cell subpopulations in a Kenyan cohort (HUM8P.332). The Journal of Immunology 2014. [DOI: 10.4049/jimmunol.192.supp.185.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Chronic infections during pregnancy can expose the fetus to foreign antigens leading to cytokine responses that affect fetal B cell development. We hypothesize that this exposure shifts the distribution of B cell subpopulations. Using flow cytometry, we examined the proportions of various B cell subpopulations in cord blood from North American (Nam) and Kenyan neonates. NAm neonates had no prenatal infectious exposures whereas Kenyan neonates examined had prenatal HIV, CMV, or P falciparum exposure, or no infectious exposures. We also measured the plasma levels of pro-inflammatory biomarkers and BAFF in NAm and Kenyan cord plasma. We found that Kenyan neonates exposed to prenatal infections had greater proportions of memory B cells (CD19+CD27+), especially the activated (CD19+CD27+CD21-IgD-) memory B cells compared to NAm neonates. HIV exposed neonates had greater proportions of atypical MBC compared to the other Kenyan infectious exposed groups. Kenyan neonates had higher levels of IP-10, TNFa, CRP, sCD14 and BAFF than NAm neonates. Among the Kenyan groups, those with prenatal infectious exposures had higher levels of INFg, IL-7, sTNFR1 and sTNFR2 compared to Kenyan neonates with no infectious exposures. These results suggest that the presence of chronic infections during pregnancy affects B cell development including activated memory B cells, some pro-inflammatory biomarkers, and BAFF levels. The functional significance of these differences needs to be further investigated.
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Affiliation(s)
- Arlene Dent
- 1Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH
- 2Pediatrics, Rainbow Babies and Children, Cleveland, OH
| | - Kee Thai Yeo
- 2Pediatrics, Rainbow Babies and Children, Cleveland, OH
| | - Paula Embury
- 1Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH
| | - Timothy Anderson
- 1Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH
| | - Peter Mungai
- 1Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH
| | - Penny Holding
- 3Mental Health, International Centre for Behavioural Studies, Mombasa, Kenya
| | - Indu Malhotra
- 1Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH
| | - Christopher King
- 1Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH
| | - James Kazura
- 1Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH
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Newman-Gerhardt S, Muiruri S, Muchiri E, Peters CJ, Morrill J, Lucas AH, King CH, Kazura J, LaBeaud AD. Potential for autoimmune pathogenesis of Rift Valley Fever virus retinitis. Am J Trop Med Hyg 2013; 89:495-7. [PMID: 23918215 DOI: 10.4269/ajtmh.12-0562] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Rift Valley Fever (RVF) is a significant threat to human health because it can progress to retinitis, encephalitis, and hemorrhagic fever. The timing of onset of Rift Valley Fever virus (RVFV) retinitis suggests an autoimmune origin. To determine whether RVFV retinitis is associated with increased levels of IgG against retinal tissue, we measured and compared levels of IgG against healthy human eye tissue by immunohistochemical analysis. We found that serum samples from RVFV-exposed Kenyans with retinitis (n = 8) were slightly more likely to have antibodies against retinal tissue than control populations, but the correlation was not statistically significant. Further investigation into the possible immune pathogenesis of RVFV retinitis could lead to improved therapies to prevent or treat this severe complication.
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Affiliation(s)
- Shoshana Newman-Gerhardt
- National Institutes of Health, Building 29B, Room 2c17, 29 Lincoln Way, Bethesda, MD 20892, USA.
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Singh BK, Bockarie MJ, Gambhir M, Siba PM, Tisch DJ, Kazura J, Michael E. Sequential modelling of the effects of mass drug treatments on anopheline-mediated lymphatic filariasis infection in Papua New Guinea. PLoS One 2013; 8:e67004. [PMID: 23826185 PMCID: PMC3691263 DOI: 10.1371/journal.pone.0067004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 05/16/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Lymphatic filariasis (LF) has been targeted by the WHO for global eradication leading to the implementation of large scale intervention programs based on annual mass drug administrations (MDA) worldwide. Recent work has indicated that locality-specific bio-ecological complexities affecting parasite transmission may complicate the prediction of LF extinction endpoints, casting uncertainty on the achievement of this initiative. One source of difficulty is the limited quantity and quality of data used to parameterize models of parasite transmission, implying the important need to update initially-derived parameter values. Sequential analysis of longitudinal data following annual MDAs will also be important to gaining new understanding of the persistence dynamics of LF. Here, we apply a Bayesian statistical-dynamical modelling framework that enables assimilation of information in human infection data recorded from communities in Papua New Guinea that underwent annual MDAs, into our previously developed model of parasite transmission, in order to examine these questions in LF ecology and control. RESULTS Biological parameters underlying transmission obtained by fitting the model to longitudinal data remained stable throughout the study period. This enabled us to reliably reconstruct the observed baseline data in each community. Endpoint estimates also showed little variation. However, the updating procedure showed a shift towards higher and less variable values for worm kill but not for any other drug-related parameters. An intriguing finding is that the stability in key biological parameters could be disrupted by a significant reduction in the vector biting rate prevailing in a locality. CONCLUSIONS Temporal invariance of biological parameters in the face of intervention perturbations indicates a robust adaptation of LF transmission to local ecological conditions. The results imply that understanding the mechanisms that underlie locally adapted transmission dynamics will be integral to identifying points of system fragility, and thus countermeasures to reliably facilitate LF extinction both locally and globally.
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Affiliation(s)
- Brajendra K Singh
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America.
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Affiliation(s)
- Clive Brown
- *Address correspondence to Clive Brown, Centers for Disease Control and Prevention, 1600 Clifton Rd., MS-E03, Atlanta, GA 30329. E-mail:
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Gambhir M, Bockarie M, Tisch D, Kazura J, Remais J, Spear R, Michael E. Geographic and ecologic heterogeneity in elimination thresholds for the major vector-borne helminthic disease, lymphatic filariasis. BMC Biol 2010; 8:22. [PMID: 20236528 PMCID: PMC2848205 DOI: 10.1186/1741-7007-8-22] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Accepted: 03/17/2010] [Indexed: 11/25/2022] Open
Abstract
Background Large-scale intervention programmes to control or eliminate several infectious diseases are currently underway worldwide. However, a major unresolved question remains: what are reasonable stopping points for these programmes? Recent theoretical work has highlighted how the ecological complexity and heterogeneity inherent in the transmission dynamics of macroparasites can result in elimination thresholds that vary between local communities. Here, we examine the empirical evidence for this hypothesis and its implications for the global elimination of the major macroparasitic disease, lymphatic filariasis, by applying a novel Bayesian computer simulation procedure to fit a dynamic model of the transmission of this parasitic disease to field data from nine villages with different ecological and geographical characteristics. Baseline lymphatic filariasis microfilarial age-prevalence data from three geographically distinct endemic regions, across which the major vector populations implicated in parasite transmission also differed, were used to fit and calibrate the relevant vector-specific filariasis transmission models. Ensembles of parasite elimination thresholds, generated using the Bayesian fitting procedure, were then examined in order to evaluate site-specific heterogeneity in the values of these thresholds and investigate the ecological factors that may underlie such variability Results We show that parameters of density-dependent functions relating to immunity, parasite establishment, as well as parasite aggregation, varied significantly between the nine different settings, contributing to locally varying filarial elimination thresholds. Parasite elimination thresholds predicted for the settings in which the mosquito vector is anopheline were, however, found to be higher than those in which the mosquito is culicine, substantiating our previous theoretical findings. The results also indicate that the probability that the parasite will be eliminated following six rounds of Mass Drug Administration with diethylcarbamazine and albendazole decreases markedly but non-linearly as the annual biting rate and parasite reproduction number increases. Conclusions This paper shows that specific ecological conditions in a community can lead to significant local differences in population dynamics and, consequently, elimination threshold estimates for lymphatic filariasis. These findings, and the difficulty of measuring the key local parameters (infection aggregation and acquired immunity) governing differences in transmission thresholds between communities, mean that it is necessary for us to rethink the utility of the current anticipatory approaches for achieving the elimination of filariasis both locally and globally.
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Affiliation(s)
- Manoj Gambhir
- Department of Infectious Disease Epidemiology, Imperial College London, UK.
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Müller I, Genton B, Rare L, Kiniboro B, Kastens W, Zimmerman P, Kazura J, Alpers M, Smith TA. Three different Plasmodium species show similar patterns of clinical tolerance of malaria infection. Malar J 2009; 8:158. [PMID: 19602275 PMCID: PMC2719654 DOI: 10.1186/1475-2875-8-158] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Accepted: 07/14/2009] [Indexed: 11/11/2022] Open
Abstract
Background In areas where malaria endemicity is high, many people harbour blood stage parasites without acute febrile illness, complicating the estimation of disease burden from infection data. For Plasmodium falciparum the density of parasitaemia that can be tolerated is low in the youngest children, but reaches a maximum in the age groups at highest risk of infection. There is little data on the age dependence of tolerance in other species of human malaria. Methods Parasite densities measured in 24,386 presumptive malaria cases at two local health centres in the Wosera area of Papua New Guinea were compared with the distributions of parasite densities recorded in community surveys in the same area. We then analyse the proportions of cases attributable to each of Plasmodium falciparum, P. vivax, and P. malariae as functions of parasite density and age using a latent class model. These attributable fractions are then used to compute the incidence of attributable disease. Results Overall 33.3%, 6.1%, and 0.1% of the presumptive cases were attributable to P. falciparum, P. vivax, and P. malariae respectively. The incidence of attributable disease and parasite density broadly follow similar age patterns. The logarithm of the incidence of acute illness is approximately proportion to the logarithm of the parasite density for all three malaria species, with little age variation in the relationship for P. vivax or P. malariae. P. falciparum shows more age variation in disease incidence at given levels of parasitaemia than the other species. Conclusion The similarities between Plasmodium species in the relationships between parasite density and risk of attributable disease are compatible with the hypothesis that pan-specific mechanisms may regulate tolerance to different human Plasmodia. A straightforward mathematical expression might be used to project disease burden from parasite density distributions assessed in community-based parasitological surveys.
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Affiliation(s)
- Ivo Müller
- Department of Public Health & Epidemiology, Swiss Tropical Institute, Basel, Switzerland.
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Ostrout ND, McHugh MM, Brustoski K, Kazura J. Phenotype and functional properties of Vaccinia specific CD8+ T cells (43.12). The Journal of Immunology 2007. [DOI: 10.4049/jimmunol.178.supp.43.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Abstract
Memory CD8+ T cells play a significant role in mediating protective immunity from pathogens, particularly viruses and intracellular bacteria. Inducing the optimal response, from both a quantitative and qualitative perspective, has been a research priority for determining the effectiveness of new vaccines. Depending on the pathogen, central memory (TCM) or effector memory (TEM) may be more important in providing adequate protection. Therefore, when developing new vaccines, it is important to realize which memory CD8+ T cell subset is vital and potentially ‘drive’ the response to elicit a protective level ratio in favor of one subset. Here we describe the phenotype of vaccinia specific memory CD8+ T cells. TEMRA+ memory T cells produce the most IFN-γ of any memory subset and are present in individuals last vaccinated over 30 years ago. Concurrently, we address the development of memory CD8+ T cells upon administration of Dryvax, as well as new smallpox vaccines such as Modified Vaccinia Ankara (MVA) in a murine model. Previous studies have indicated that TEM appear to provide better secondary protection than TCM and the data presented here indicate that these cells are maintained long term (>30 years). Therefore, we propose that new smallpox vaccines, such as MVA, should elicit a memory cell population in favor of TEM similar to that induced by Dryvax or other traditional smallpox vaccines.
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Affiliation(s)
- Nicholas D Ostrout
- Pathology-Immunology, Case Western Reserve University, 2103 Cornell Rd., Room 4104, Cleveland, OH, 44106
| | - Marilyn M McHugh
- Pathology-Immunology, Case Western Reserve University, 2103 Cornell Rd., Room 4104, Cleveland, OH, 44106
| | - Kim Brustoski
- Pathology-Immunology, Case Western Reserve University, 2103 Cornell Rd., Room 4104, Cleveland, OH, 44106
| | - James Kazura
- Pathology-Immunology, Case Western Reserve University, 2103 Cornell Rd., Room 4104, Cleveland, OH, 44106
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Moormann AM, Chelimo K, Sumba OP, Lutzke ML, Ploutz-Snyder R, Newton D, Kazura J, Rochford R. Exposure to holoendemic malaria results in elevated Epstein-Barr virus loads in children. J Infect Dis 2005; 191:1233-8. [PMID: 15776368 DOI: 10.1086/428910] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2004] [Accepted: 11/12/2004] [Indexed: 11/03/2022] Open
Abstract
Perennial and intense malaria transmission (holoendemic malaria) and Epstein-Barr virus (EBV) infection are 2 cofactors in the pathogenesis of endemic Burkitt lymphoma (eBL). In the present study, we compared EBV loads in children living in 2 regions of Kenya with differing malaria transmission intensities: Kisumu District, where malaria transmission is holoendemic, and Nandi District, where malaria transmission is sporadic. For comparison, blood samples were also obtained from US adults, Kenyan adults, and patients with eBL. Extraction of DNA from blood and quantification by polymerase chain reaction give an EBV load estimate that reflects the number of EBV-infected B cells. We observed a significant linear trend in mean EBV load, with the lowest EBV load detected in US adults and increasing EBV loads detected in Kenyan adults, Nandi children, Kisumu children, and patients with eBL, respectively. In addition, EBV loads were significantly higher in Kisumu children 1-4 years of age than in Nandi children of the same age. Our results support the hypothesis that repeated malaria infections in very young children modulate the persistence of EBV and increase the risk for the development of eBL.
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Affiliation(s)
- Ann M Moormann
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, USA
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Moormann A, Cao K, Masaberg C, Sumba O, Koech D, Ng J, Hartzman R, Kazura J, Fernández-Viña M. HLA-A, -B and -Cw allele frequencies in a Nandi population from Kenya. Hum Immunol 2004. [DOI: 10.1016/j.humimm.2004.08.075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Moormann A, Cao K, Masaberg C, Sumba O, Koech D, Ng J, Hartzman R, Kazura J, Fernández-Viña M. HLA-A, -B and -Cw allele frequencies in a Luo population from Kenya. Hum Immunol 2004. [DOI: 10.1016/j.humimm.2004.08.074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Cao K, Moormann AM, Lyke KE, Masaberg C, Sumba OP, Doumbo OK, Koech D, Lancaster A, Nelson M, Meyer D, Single R, Hartzman RJ, Plowe CV, Kazura J, Mann DL, Sztein MB, Thomson G, Fernández-Viña MA. Differentiation between African populations is evidenced by the diversity of alleles and haplotypes of HLA class I loci. ACTA ACUST UNITED AC 2004; 63:293-325. [PMID: 15009803 DOI: 10.1111/j.0001-2815.2004.00192.x] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The allelic and haplotypic diversity of the HLA-A, HLA-B, and HLA-C loci was investigated in 852 subjects from five sub-Saharan populations from Kenya (Nandi and Luo), Mali (Dogon), Uganda, and Zambia. Distributions of genotypes at all loci and in all populations fit Hardy-Weinberg equilibrium expectations. There was not a single allele predominant at any of the loci in these populations, with the exception of A*3002 [allele frequency (AF) = 0.233] in Zambians and Cw*1601 (AF = 0.283) in Malians. This distribution was consistent with balancing selection for all class I loci in all populations, which was evidenced by the homozygosity F statistic that was less than that expected under neutrality. Only in the A locus in Zambians and the C locus in Malians, the AF distribution was very close to neutrality expectations. There were six instances in which there were significant deviations of allele distributions from neutrality in the direction of balancing selection. All allelic lineages from each of the class I loci were found in all the African populations. Several alleles of these loci have intermediate frequencies (AF = 0.020-0.150) and seem to appear only in the African populations. Most of these alleles are widely distributed in the African continent and their origin may predate the separation of linguistic groups. In contrast to native American and other populations, the African populations do not seem to show extensive allelic diversification within lineages, with the exception of the groups of alleles A*02, A*30, B*57, and B*58. The alleles of human leukocyte antigen (HLA)-B are in strong linkage disequilibrium (LD) with alleles of the C locus, and the sets of B/C haplotypes are found in several populations. The associations between A alleles with C-blocks are weaker, and only a few A/B/C haplotypes (A*0201-B*4501-Cw*1601; A*2301-B*1503-Cw*0202; A*7401-B* 1503-Cw*0202; A*2902-B*4201-Cw*1701; A*3001-B*4201-Cw*1701; and A*3601-B*5301-Cw*0401) are found in multiple populations with intermediate frequencies [haplotype frequency (HF) = 0.010-0.100]. The strength of the LD associations between alleles of HLA-A and HLA-B loci and those of HLA-B and HLA-C loci was on average of the same or higher magnitude as those observed in other non-African populations for the same pairs of loci. Comparison of the genetic distances measured by the distribution of alleles at the HLA class I loci in the sub-Saharan populations included in this and other studies indicate that the Luo population from western Kenya has the closest distance with virtually all sub-Saharan population so far studied for HLA-A, a finding consistent with the putative origin of modern humans in East Africa. In all African populations, the genetic distances between each other are greater than those observed between European populations. The remarkable current allelic and haplotypic diversity in the HLA system as well as their variable distribution in different sub-Saharan populations is probably the result of evolutionary forces and environments that have acted on each individual population or in their ancestors. In this regard, the genetic diversity of the HLA system in African populations poses practical challenges for the design of T-cell vaccines and for the transplantation medical community to find HLA-matched unrelated donors for patients in need of an allogeneic transplant.
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Affiliation(s)
- K Cao
- Department of Oncology, Georgetown University, Washington, DC, USA
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Bockarie M, Kazura J, Alexander N, Dagoro H, Bockarie F, Perry R, Alpers M. Transmission dynamics of Wuchereria bancrofti in East Sepik Province, Papua New Guinea. Am J Trop Med Hyg 1996; 54:577-81. [PMID: 8686774 DOI: 10.4269/ajtmh.1996.54.577] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Bancroftian filariasis is endemic in many areas of Papua New Guinea. This study describes the entomologic indices of transmission near Dreikikir in East Sepik Province, Papua New Guinea. A total of 1,735 culicine mosquitoes, including Culex and Mansonia species, were dissected, but none were infected with filarial larvae. In contrast, Anopheles punctulatus and An. koliensis were found to be potential vectors: 7.3% of Anopheles were infected and the mean number of first- to third-stage larvae per infected mosquito was 2.7. Transmission indices varied significantly in five villages located within a 50-km radius of each other. Annual biting rates ranged from 4,789 to 48,020 bites/person/year; annual infective biting rates from 15 to 836/person/year; and annual transmission potential from 31 to 2,340 third-stage larvae/person/year. Monthly transmission potential and monthly infective biting rate varied significantly in each village, with the highest indices of transmission observed in villages nearest sites where puddles formed in river beds during the dry season. These data indicate that there is small area variation in the intensity and temporal pattern of filariasis transmission and that culicine mosquitoes are not important vectors of W. bancrofti in this area.
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Affiliation(s)
- M Bockarie
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
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Kazura J, Greenberg J, Perry R, Weil G, Day K, Alpers M. Comparison of single-dose diethylcarbamazine and ivermectin for treatment of bancroftian filariasis in Papua New Guinea. Am J Trop Med Hyg 1993; 49:804-11. [PMID: 8279647 DOI: 10.4269/ajtmh.1993.49.804] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
This double-blind study compared the clinical safety and parasitologic efficacy of single-dose regimens of diethylcarbamazine (DEC) and ivermectin for treatment of bancroftian filariasis in Papua New Guinea. Five groups of 10 men each with mean levels of parasitemia ranging from 2,985 to 5,185 microfilariae (mf)/ml were given DEC (6 mg/kg of body weight one time or 1 mg/kg, then 6 mg/kg four days later) or ivermectin (220 micrograms/kg; 20 micrograms/kg, then 200 micrograms/kg four days later or 20 micrograms/kg, then 400 micrograms/kg four days later). No significant side effects (e.g., acute adenolymphangitis, fever lasting more than eight hours, hypotension) were observed in any of the five treatment groups. The magnitude of reduction in microfilaremia was greater (P < 0.01) for the three ivermectin groups versus the two DEC groups in the first 30 days after drug administration (mf levels < 1% of pretreatment values versus 22.6-41.5%, respectively). At 90 and 180 days, mf levels continued to decrease in the DEC groups whereas they increased in the ivermectin groups given a total dose of 220 micrograms/kg. Eighteen months after drug administration, individuals given DEC or 420 micrograms/kg of ivermectin had the greatest degree of reduction in microfilaremia (86-90% compared with the pretreatment values). Decreases in parasite antigenemia measured by enzyme-linked immunosorbent assay for a secreted 200-kD adult worm antigen were greatest for the single-dose DEC group (39.7% decrease relative to the pretreatment level versus 7.8-15.7% for the ivermectin groups). These results indicate that single-dose DEC and ivermectin are well-tolerated by Wuchereria bancrofti-infected individuals with high levels of microfilaremia.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Kazura
- Division of Geographic Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio
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Ratnoff OD, Gleich GJ, Shurin SB, Kazura J, Everson B, Embury P. Inhibition of the activation of hageman factor (factor XII) by eosinophils and eosinophilic constituents. Am J Hematol 1993; 42:138-45. [PMID: 8416290 DOI: 10.1002/ajh.2830420127] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Several syndromes characterized by striking eosinophilia may be complicated by thrombosis. The experiments described indicate that, paradoxically, eosinophils and certain of their constituents inhibit the activation of Hageman factor (HF, factor XII). In earlier studies, suspensions of mixed types of granulocytes, other nucleated peripheral blood cells, and platelets inhibited activation of Hageman factor by ellagic acid, glass, and sulfatides. After these cells were sedimented by centrifugation, the supernatant fluids were also inhibitory. No attempt had been made earlier to distinguish among different granulocytic species. In the present study, suspensions of eosinophils and the supernatant fluid after eosinophils had been separated by centrifugation inhibited activation of Hageman factor by ellagic acid. The protein concentration of that amount of supernatant fluid that inhibited activation by about half was 16 micrograms/ml, approximately the same as had been described for suspensions of peripheral blood mononuclear cells. Activation of Hageman factor by ellagic acid was also inhibited by certain constituents of eosinophils, including eosinophil peroxidase, eosinophil major basic protein and eosinophil cationic protein. Inhibition was not specific for ellagic acid-induced activation of Hageman factor, as inhibition was also observed with sulfatide-induced activation. Inhibition was presumably related to neutralization of the negative charge of activators of Hageman factor. Thus, bismuth subgallate, a particulate activator of Hageman factor, was no longer effective after it had been exposed to eosinophil cationic protein. The observations reported here raise the question of whether in vivo eosinophils modulate certain of the defense reactions ascribed to Hageman factor.
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Affiliation(s)
- O D Ratnoff
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio
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Lal RB, Brodine S, Kazura J, Mbidde-Katonga E, Yanagihara R, Roberts C. Sensitivity and specificity of a recombinant transmembrane glycoprotein (rgp21)-spiked western immunoblot for serological confirmation of human T-cell lymphotropic virus type I and type II infections. J Clin Microbiol 1992; 30:296-9. [PMID: 1347047 PMCID: PMC265049 DOI: 10.1128/jcm.30.2.296-299.1992] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Serum specimens (n = 2,712) obtained from individuals residing in diverse geographic regions and categorized as seropositive (n = 122), seroindeterminate (n = 523), or seronegative (n = 2,067) for human T-cell lymphotropic virus (HTLV) infection in accordance with U.S. Public Health Service guidelines were retested by recombinant transmembrane protein (rgp21)-spiked Western immunoblotting. Of the 122 HTLV-positive specimens, those from 85 of 85 (100%) U.S. blood donors, 2 of 2 (100%) Brazilians, 1 of 2 (50%) Indonesians, 14 of 14 (100%) Solomon Islanders, and 18 of 19 (95%) Papua New Guineans reacted with rgp21, yielding an overall sensitivity of 98% (120 of 122). Specimens from individuals whose infections were confirmed to be HTLV type I or HTLV type II by the polymerase chain reaction assay reacted equally well with rgp21. Of the 523 HTLV-indeterminate specimens, those from 21 of 379 (5.5%) U.S. blood donors, 3 of 6 (50%) Brazilians, 10 of 23 (44%) Ugandans, 8 of 49 (16%) Indonesians, 4 of 36 (11%) Solomon Islanders, and 5 of 30 (17%) Papua New Guineans reacted with rgp21. None of these 51 specimens reacted with native gp46 and/or gp61/68 in a radioimmunoprecipitation assay, suggesting a false-positive reaction (9.75%). Of the 2,067 HTLV-negative specimens, 12 reacted with rgp21, yielding a false-positivity rate of 0.6%. These data indicate that while detection of rgp21 is highly sensitive, it can yield false-positive results. Thus, specimens exhibiting reactivity with rgp21 in the absence of reactivity with native gp46 and/or gp61/68 by Western blot should be tested further by a radioimmunoprecipitation assay to verify HTLV type I or type II infection.
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Affiliation(s)
- R B Lal
- Retrovirus Diseases Branch, Center for Disease Control, Atlanta, Georgia 30333
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Abstract
Placement of Broviac catheters for venous access resulted in metastatic tumor implantation along the catheter tracts in an adult with multiple myeloma and in a child with Burkitt's lymphoma. Both complications occurred in the setting of advanced malignancy. The tissue injury produced during the creation of the catheter tunnel may create an environment favorable for metastatic tumor growth. Swelling along catheter tunnel tracts will most frequently result from hematoma or infection, but the rare occurrence of tumor implantation should be considered. Biopsy is diagnostic.
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Forsyth KP, Spark R, Kazura J, Brown GV, Peters P, Heywood P, Dissanayake S, Mitchell GF. A monoclonal antibody-based immunoradiometric assay for detection of circulating antigen in Bancroftian filariasis. The Journal of Immunology 1985. [DOI: 10.4049/jimmunol.134.2.1172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
A monoclonal antibody designated Gib 13 has been used in an immunoradiometric assay (IRMA) to detect circulating antigen in the sera of Wuchereria bancrofti-infected subjects from an endemic area of Papua New Guinea. A clear association between the presence of patent infection and the Gib 13 target epitope in serum was established because 93% of microfilaremic individuals were antigen-positive. Moreover, there was a significant correlation between levels of serum antigen and blood microfilarial counts. Detection of circulating antigen in amicrofilaremic subjects with acute symptoms of lymphatic filariasis, and 53% of asymptomatic amicrofilaremic subjects, but not in nonendemic controls, suggests that the Gib 13 IRMA will also be of value in the diagnosis of occult filariasis. However, as in all IRMA based on detection of potentially immunogenic molecules in man, antibodies can be expected to be the major contributor to reduced sensitivity of the assay.
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Forsyth KP, Spark R, Kazura J, Brown GV, Peters P, Heywood P, Dissanayake S, Mitchell GF. A monoclonal antibody-based immunoradiometric assay for detection of circulating antigen in Bancroftian filariasis. J Immunol 1985; 134:1172-7. [PMID: 2578153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A monoclonal antibody designated Gib 13 has been used in an immunoradiometric assay (IRMA) to detect circulating antigen in the sera of Wuchereria bancrofti-infected subjects from an endemic area of Papua New Guinea. A clear association between the presence of patent infection and the Gib 13 target epitope in serum was established because 93% of microfilaremic individuals were antigen-positive. Moreover, there was a significant correlation between levels of serum antigen and blood microfilarial counts. Detection of circulating antigen in amicrofilaremic subjects with acute symptoms of lymphatic filariasis, and 53% of asymptomatic amicrofilaremic subjects, but not in nonendemic controls, suggests that the Gib 13 IRMA will also be of value in the diagnosis of occult filariasis. However, as in all IRMA based on detection of potentially immunogenic molecules in man, antibodies can be expected to be the major contributor to reduced sensitivity of the assay.
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