Abstract:
Background: Diversity in Plasmodium falciparum poses a major threat to malaria control and
elimination interventions. This study utilized 12 polymorphic microsatellite (MS) markers and the
Msp2 marker to examine diversity, multiplicity of infection (MOI) as well as the population structure
of parasites circulating in two sites separated by about 92 km and with varying malaria transmission
intensities within the Greater Accra Region of Ghana. Methods: The diversity and MOI of P. falciparum
parasites in 160 non-symptomatic volunteers living in Obom (high malaria transmission intensity)
and Asutsuare (low malaria transmission intensity) aged between 8 and 60 years was determined
using Msp2 genotyping and microsatellite analysis. Results: The prevalence of asymptomatic
P. falciparum carriers as well as the parasite density of infections was significantly higher in Obom
than in Asutsuare. Samples from Asutsuare and Obom were 100% and 65% clonal, respectively,
by Msp2 genotyping but decreased to 50% and 5%, respectively, when determined by MS analysis.
The genetic composition of parasites from Obom and Asutsuare were highly distinct, with parasites
from Obom being more diverse than those from Asutsuare. Conclusion: Plasmodium falciparum
parasites circulating in Obom are genetically more diverse and distinct from those circulating in
Asutsuare. The MOI in samples from both Obom and Asutsuare increased when assessed by MS
analysis relative to MSP2 genotyping. The TA40 and TA87 loci are useful markers for estimating MOI
in high and low parasite prevalence settings.