Variation in exposure to Anopheles gambiae salivary gland peptide (gSG6-P1) across different malaria transmission settings in the western Kenya highlands

Malaria Journal

Research

Andrew K Githeko¹  John Ong’echa¹  Yaw Afrane¹  John Larbi²  Bernard W Lawson²  Kingsley Badu³  Franck Remoue⁴  Guiyun Yan⁵  Guofa Zhou⁵  Joram Siangla⁶ 

[1] Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya;Department of Theoretical and Applied Biology, College of Sciences, Kwame Nkrumah, University of Science & Technology, Kumasi, Ghana;Department of Theoretical and Applied Biology, College of Sciences, Kwame Nkrumah, University of Science & Technology, Kumasi, Ghana;Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya;Institute of Research for Development (IRD), MIVEGEC unit - (IRD224-UM1-UM2-CNRS 5290), Cotonou, Benin;Program in Public Health, College of Health Sciences, University of California at Irvine, 92697, Irvine, CA, USA;Walter Reed Project, United States Army Medical Research Unit-Kenya, Kisumu;

关键词: Malaria;    Malaria Transmission;    Valley Bottom;    Parasite Prevalence;    Entomological Inoculation Rate;   

DOI  :  10.1186/1475-2875-11-318

 received in 2012-06-22, accepted in 2012-09-06,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundThe existing metrics of malaria transmission are limited in sensitivity under low transmission intensity. Robust surveillance systems are needed as interventions to monitor reduced transmission and prevention of rapid reintroduction. Serological tools based on antibody responses to parasite and vector antigens are potential tools for transmission measurements. The current study sought to evaluate antibody responses to Anopheles gambiae salivary gland peptide (gSG6- P1), as a biomarker of human exposure to Anopheles bites, in different transmission settings and seasons. The comparison between anti-MSP-119 IgG immune responders and non-responders allowed exploring the robustness of the gSG6-P1 peptide as a surveillance tool in an area of decreasing malaria transmission.MethodsTotal IgG levels to gSG6-P1 were measured in an age-stratified cohort (< 5, 5–14 and ≥ 15 years) in a total of 1,366 participants from three localities in western Kenya [Kisii (hypoendemic), Kakamega (mesoendemic), and Kombewa (hyperendemic)] including 607 sera that were additionally tested for MSP-119 specific responses during a low and a high malaria transmission seasons. Antibody prevalence and levels were compared between localities with different transmission intensities. Regression analysis was performed to examine the association between gSG6-P1 and MSP-119 seroprevalence and parasite prevalence.ResultSeroprevalence of gSG6-P1 in the uphill population was 36% while it was 50% valley bottom (χ2 = 13.2, df = 1, p < 0.001). Median gSG6-P1 antibody levels in the Valley bottom were twice as high as that observed in the uphill population [4.50 vs. 2.05, p < 0.001] and showed seasonal variation. The odds of gSG6-P1 seropositives having MSP-119 antibodies were almost three times higher than the odds of seronegatives (OR = 2.87, 95% CI [1.977, 4.176]). The observed parasite prevalence for Kisii, Kakamega and Kombewa were 4%, 19.7% and 44.6% whilst the equivalent gSG6-P1 seroprevalence were 28%, 34% and 54%, respectively.ConclusionThe seroprevalence of IgG to gSG6-P1 was sensitive and robust in distinguishing between hypo, meso and hyper transmission settings and seasonal fluctuations.

【 授权许可】

CC BY   
© Badu et al.; licensee BioMed Central Ltd. 2012