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|Title: ||Marked variation in MSP-119 antibody responses to malaria in western Kenyan highlands|
|Authors: ||Badu, Kingsley|
Afrane, Yaw Asare
Larbi, John Asiedu
Stewart, Virginia Ann
|Issue Date: ||1-Dec-2012|
|Publisher: ||BioMed Central Ltd.|
|Citation: ||Badu et al. BMC Infectious Diseases 2012, 12:50 http://www.biomedcentral.com/1471-2334/12/50|
|Abstract: ||Background: Assessment of malaria endemicity at different altitudes and transmission intensities, in the era of
dwindling vector densities in the highlands, will provide valuable information for malaria control and surveillance.
Measurement of serum anti-malarial antibodies is a useful marker of malaria exposure that indicates long-term
transmission potential. We studied the serologic evidence of malaria endemicity at two highland sites along a
transmission intensity cline. An improved understanding of the micro-geographic variation in malaria exposure in
the highland ecosystems will be relevant in planning effective malaria control.
Methods: Total IgG levels to Plasmodium falciparum MSP-119 were measured in an age-stratified cohort (< 5, 5-14
and ≥ 15 years) in 795 participants from an uphill and valley bottom residents during low and high malaria
transmission seasons. Antibody prevalence and level was compared between different localities. Regression analysis
was performed to examine the association between antibody prevalence and parasite prevalence. Age-specific
MSP-119 seroprevalence data was fitted to a simple reversible catalytic model to investigate the relationship
between parasite exposure and age.
Results: Higher MSP-119 seroprevalence and density were observed in the valley residents than in the uphill
dwellers. Adults (> 15 years) recorded high and stable immune response in spite of changing seasons. Lower
responses were observed in children (≤ 15 years), which, fluctuated with changing seasons particularly in the valley
residents. In the uphill population, annual seroconversion rate (SCR) was 8.3% and reversion rate was 3.0%, with
seroprevalence reaching a plateau of 73.3% by age of 20. Contrary, in the valley bottom population, the annual
SCR was 35.8% and the annual seroreversion rate was 3.5%, and seroprevalence in the population had reached
91.2% by age 10.
Conclusion: The study reveals the micro-geographic variation in malaria endemicity in the highland eco-system;
this validates the usefulness of sero-epidemiological tools in assessing malaria endemicity in the era of decreasing
sensitivity of conventional tools.|
|Description: ||An article published by BioMed Central Ltd. and also available at http://www.biomedcentral.com/1471-2334/12/50|
|Appears in Collections:||College of Science|
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