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Evidence for a reduced effect of chloroquine against Plasmodium falciparum in alpha + ‐thalassaemic children
Author(s) -
Mockenhaupt Frank P.,
May Jürgen,
Bergqvist Yngve,
Meyer Christian G.,
Falusi Adeyinka G.,
Bienzle Ulrich
Publication year - 2001
Publication title -
tropical medicine and international health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.056
H-Index - 114
eISSN - 1365-3156
pISSN - 1360-2276
DOI - 10.1046/j.1365-3156.2001.00688.x
Subject(s) - malaria , plasmodium falciparum , chloroquine , medicine , thalassemia , hemoglobinopathy , alpha thalassemia , immunology , odds ratio , genotype , biology , hemolytic anemia , genetics , gene
Alpha‐thalassaemia is common in malaria‐endemic regions and is considered to confer protection from clinical disease due to infection with Plasmodium falciparum. In vitro , sensitivity to chloroquine (CQ) of P. falciparum infecting alpha‐thalassaemic erythrocytes is reduced. We examined, in a cross‐sectional study of 405 Nigerian children, associations between alpha‐globin genotypes, blood concentrations of CQ, and P. falciparum parasitaemia. Of the children, 44% were alpha + ‐thalassaemic (36.8% heterozygous, 7.6% homozygous). CQ in blood and P. falciparum ‐infection were observed in 52 and 80%, respectively. CQ was more frequently found in homozygous alpha + ‐thalassaemic (71%) than in non‐thalassaemic children (50%; odds ratio, 2.42; 95% confidence interval, 1.01–5.8). Among children with CQ in blood and despite similar drug concentrations, alpha + ‐thalassaemic individuals had fewer infections below the threshold of microscopy which were detectable by PCR only, and they had a higher prevalence of elevated parasitaemia than non‐thalassaemic children. No such differences were discernible among drug‐free children. CQ displays a lowered efficacy in the suppression of P. falciparum parasitaemia in alpha + ‐thalassaemic children; hence protection against malaria due to alpha + ‐thalassaemia may be obscured in areas of intense CQ usage. Moreover, alpha + ‐thalassaemia may contribute to the expansion of CQ resistance.