Effects of permethrin-treated bed nets on immunity to malaria in western Kenya II. Antibody responses in young children in an area of intense malaria transmission
Kariuki, S.K.; Lal, A.A.; Terlouw, D.J.; ter Kuile, F.O.; Ong'echa, J.M.O.; Phillips-Howard, P.A.; Orago, A.S.S.; Kolczak, M.S.; Hawley, W.A.; Nahlen, B.L.; Shi, Y.P.
American Journal of Tropical Medicine and Hygiene 68(4 Suppl): 108-114
2003
ISSN/ISBN: 0002-9637 PMID: 12749493 Document Number: 558426
As part of a large community-based trial on the impact of insecticide (permethrin)-treated bed nets (ITNs) on childhood morbidity and mortality in an area of intense perennial malaria transmission in western Kenya, we assessed the effects of ITNs on malaria-specific humoral responses in young children. The IgG responses to Plasmodium falciparum pre-erythrocytic antigens circumsporozoite protein (CSP) and liver stage antigen-1 (LSA-1) and the blood stage antigen merozoite surface protein-1 (MSP-1(19) kD) in children less than three years old were investigated during a series of cross-sectional surveys. At 14 and 22 months after the introduction of ITNs, the frequencies and levels of IgG to CSP and LSA-1 were significantly lower in children from ITN villages than in children from control villages (P < 0.001). In contrast, the prevalence of IgG to MSP-1 was significantly higher in children from ITN villages at 14 months (P = 0.0069), but not at 22 months. Our results show that decreased exposure by ITNs reduces IgG responses to pre-erythrocytic antigens, but there was no evidence that two years of ITN use compromises IgG responses to blood stage antigens in these young children in this malaria holoendemic area.