The seroepidemiology of malaria in Middle America. V. Antibody responses in an indicator population from an endemic area with attack phase antimalaria activities
Warren, M.; Collins, W.E.; Jeffery, G.M.; Skinner, J.C.
American Journal of Tropical Medicine and Hygiene 32(6): 1209-1215
1983
ISSN/ISBN: 0002-9637 PMID: 6359903 Document Number: 200432
Serologic assessment was carried out in a sample of the population living in an area endemic for malaria in which control measures were being applied. The study area was in El Salvador, Central America, and antimalarial activities consisted of the residual application of the pesticide, propoxur [for the control of the vector Anopheles albimanus], and drug distribution through a combination of active and passive case detection. Indirect fluorescent antibody (IFA) response to Plasmodium vivax and P. falciparum antigens were determined on 4 occasions, at .apprx. 6 mo. intervals. The study population consisted of 1 resident from each of 268 widely distributed houses. Each person was treated with a curative course of chloroquine and primaquine at the beginning of the investigation. An increase in the proportion of positive IFA responses (.gtoreq. 1:20) and an increasing number of serologic conversions (i.e., from negative to positive or a 2-fold increase in titer) during the course of the 18 mo. study confirmed continued transmission of malaria. The presence of parasites in some individuals without associated serologic changes is discussed.