Molecular analysis of two local falciparum malaria outbreaks on the French Guiana coast confirms the msp1 B-K1/ varD genotype association with severe malaria

Background Plasmodium falciparum outbreaks can occur in the coastal area of French Guiana, where the population is essentially non-immune. Two sporadic outbreaks were observed, including one with severe malaria cases. To characterize these outbreaks and verify previous observations of specific genotype characteristics in severe malaria in this area, all cases from each outbreak were studied. Methods P. falciparum genotypes for six genetic loci were determined by PCR amplification from peripheral blood parasites. The msp1/ block2 and msp2 genotypes were determined by DNA sequencing. Microsatellite and varD genotyping was based on size polymorphism and locus-specific amplification. Results The outbreak including severe malaria cases was associated with a single genotype. The other mild malaria outbreak was due to at least five distinct genotypes. Conclusion Two distinct types of outbreak occured despite systematic and sustained deployement of malaria control measures, indicating a need for reinforced vigilance. The varD /B-K1 msp1 linkage and its association with severe malaria in this area was confirmed.