Relationship between the intensity of exposure to malaria parasites and infection in the Usambara mountains, Tanzania

Bodker, R.; Msangeni, H.A.; Kisinza, W.; Lindsay, S.W.

Abstract

The relationship between exposure to Plasmodium falciparum malaria and parasite density and prevalence was studied in six communities along an altitude transect. Prevalence of parasitemia in children decreased by 5% for every 100 meter increase in altitude from 82% in the lowlands at 300 meters to 12% in the highlands at 1,700 meters. This decrease in prevalence corresponded to a 1,000-fold reduction in transmission intensity. The ability to suppress parasite density and prevalence with age increased proportionally with increasing transmission intensity when transmission rates were higher than 0.1 infective bites per year, but developed after 2–3 years of age, regardless of transmission intensity. However, at transmission rates less than 0.1 infective bites per year, prevalence remained similar in all age groups. We propose that both exposure-dependent acquired immunity and age-dependent acquired immunity regulate parasite prevalence and density and suggest that transmission control will not hinder the development of protective anti-parasite immunity.

Citation

Bodker, R., Msangeni, H., Kisinza, W., & Lindsay, S. (2006). Relationship between the intensity of exposure to malaria parasites and infection in the Usambara mountains, Tanzania. American Journal of Tropical Medicine and Hygiene, 74(5), 716-723. https://doi.org/10.4269/ajtmh.2006.74.716

• Journal Article Type: Article
• Acceptance Date: Sep 21, 2005
• Online Publication Date: Mar 30, 2006
• Publication Date: May 1, 2006
• Deposit Date: May 17, 2007
• Journal: American Journal of Tropical Medicine and Hygiene
• Print ISSN: 0002-9637
• Electronic ISSN: 1476-1645
• Publisher: American Society of Tropical Medicine and Hygiene
• Peer Reviewed: Peer Reviewed
• Volume: 74
• Issue: 5
• Pages: 716-723
• DOI: https://doi.org/10.4269/ajtmh.2006.74.716
• Public URL: https://durham-repository.worktribe.com/output/1556035