Allelic frequency of msp2 and glurp genes in Plasmodium falciparum isolates from Awka, Anambra, Nigeria.

Introduction: The genetic diversity of Plasmodium falciparum correlates with its pathogenicity, therefore design of evidence-based intervention strategies to eradicate malaria requires genetic diversity surveillance. This study characterised the allelic frequencies and genetic diversity of P. falciparum parasites isolated from Awka, Nigeria.

Materials and methods: Genomic DNA was extracted from 177 P. falciparum isolates and the polymorphic regions of the msp2 and glurp genes were genotyped by nested polymerase chain reaction (PCR).

Results: Two msp2 alleles (3D7 and FC27) were analysed. The 3D7 (93.55%) msp2 allelic family was predominant in msp2 positivie isolates. Polyclonal msp2 infection was observed in 24 (38.71%) isolates. Twenty-one distinct msp2 alleles were detected, with fragment sizes ranging from 200 bp to 1200 bp. The 300 bp allelic fragment (26.83%) was predominant for the 3D7 allele, while the 400 bp allelic fragment (29.54%) was predominant for the FC27 allele. The multiplicity of infection (MoI) in msp2 was 2.03, and the expected Heterozygosity (He) was 0.34. Sixty-nine isolates (38.98%) were positive for the RII repeat region of the glurp gene. For the glurp gene, nine alleles were detected for fragment sizes ranging from 200 bp to 1150 bp, and the most prevalent allelic fragment was 200 bp (19%). The MoI and He for the glurp gene were 0.45 and 0.98, respectively.

Conclusions: The high level of polyclonal infections with P. falciparum parasites observed in this study indicates extensive genetic diversity in the study area. The data provide important baseline information that can be implemented in developing malaria control strategies and elimination in the study area and Nigeria.