title: Drug resistant Plasmodium falciparum in an area of seasonal transmission.
abstract: Eastern Sudan lies at the edge of the malaria endemicity stratum, where transmission intensity is low and seasonal. The main malaria parasite in the region, Plasmodium falciparum, survives the long dry and transmission-free season as asymptomatic sub-patent infections, and resurges following annual rains. The short-lived annual transmission in this area precipitates cyclical malaria epidemics among the semi-immune inhabitants who resort to excessive anti-malarial drugs usage at this time of the year. Chloroquine resistance (CQR) first emerged in this area in the mid 1980s; however, subsequent surveys demonstrated that the rate of parasitological failure to CQ remained stable over a period of 8 years (1986-1993). Nevertheless, the CQR level varied between years in association with the amount of annual rain. Detailed molecular surveys revealed significant temporal fluctuations in the frequency of resistant P. falciparum genotypes, increasing during the dry season but dwindling at the start of the next transmission season. The pattern of spread of drug resistance in the area is discussed in the context of parasite biology and malaria epidemiology of this region.
authors.affiliation: School of Biological Sciences, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JT, Scotland, UK. H.Babiker@ed.ac.uk
authors.forename: Hamza A
authors.initials: HA
authors.lastname: Babiker
authors.forename: Gwiria
authors.initials: G
authors.lastname: Satti
authors.forename: Heather
authors.initials: H
authors.lastname: Ferguson
authors.forename: Riad
authors.initials: R
authors.lastname: Bayoumi
authors.forename: David
authors.initials: D
authors.lastname: Walliker
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000494:pharmacology / Q000627:therapeutic use*; D002738:Chloroquine / Q000494:pharmacology / Q000627:therapeutic use; D018562:Disease Transmission, Infectious; D018432:Drug Resistance, Multiple; D006801:Humans; D016778:Malaria, Falciparum / Q000188:drug therapy* / Q000469:parasitology / Q000635:transmission; D010963:Plasmodium falciparum / Q000187:drug effects / Q000235:genetics*; D012621:Seasons
chemical_list: D000962:Antimalarials; D002738:Chloroquine