Genetic diversity in merozoite surface protein 1 of Plasmodium falciparum isolates from Igbogbo-bayeku, Lagos, Nigeria

Abstract

Mutations in merozoite surface protein 1 (MSP1) serve as indicators of genetic diversity in Plasmodium falciparum population in a given area. Diversity in MSP1 gene of P. falciparum isolates in Igbogbo-Bayeku, a periurban settlement of Lagos, Nigeria was assessed. Malaria was diagnosed by microscopy and polymerase chain reaction (PCR). MSP1 gene polymorphisms were analyzed in P. falciparum-positive samples using allele-specific primers of the three families of MSP1 block 2. Of the 63 malaria cases, 34 (54%) were microscopic while 29 (46%) were sub-microscopic cases. The three MSP1 families were present in the P. falciparum isolates with RO33 being the most abundant (55; 87.3%). Thirteen distinct genotypes of MSP1 were observed. There were more polyclonal infections (40; 63.5%) than monoclonal infections (23; 36.5%). The multiplicity of infection (MOI) was 1.98 and the expected heterozygosity (He) was 0.64. Participants aged >8 years had significantly higher MOI (2.26±0.98) than those aged £ 8 years (1.78±0.83) (P=0.04). Polyclonal infections were similar in microscopic (23/39; 67.6%) and sub-microscopic infections (17/29; 58.6%) (P=0.46). However, polyinfections were more in microscopic (26/34; 76.5%) than in submicroscopic infections (15/29; 51.7%) (P=0.04). A high level of genetic diversity was observed in the P. falciparum isolates in this community-based study which is an indication of intense malaria transmission.