Dr Julia Mwesigwa, a clinical Epidemiologist at the MRC Unit the Gambia, led the nationwide survey and is the first-author of the paper entitled “On-going malaria transmission in The Gambia despite high coverage of control interventions: a nationwide cross-sectional survey”. The findings of a nationwide cross-sectional survey aimed at determining the prevalence of Plasmodium falciparum infection and describing its heterogeneity in The Gambia has been accepted for publication in the MALARIA JOURNAL.
The study was conducted in 36 villages across 5 regions of The Gambia, namely; West Coast Region (WCR), North Bank Region (NBR), Lower River Region (LRR), Central River Region (CRR) and Upper River Region (URR). This survey is part of an on-going prospective cohort study “Malaria transmission dynamics study” of Prof Umberto D’Alessandro, the Principal Investigator . The Malaria transmission dynamics study is jointly funded by The UK Medical Research Council (MRC) and the UK Department for International Development (DFID) under the MRC/DFID Concordat agreement.

The cross-sectional survey identified two main strata of the distribution of malaria infection across the country, using PCR-based molecular diagnostic method. The results show low transmission areas in the west, central and lower river regions of the country and relatively high transmission in URR, which is in the eastern part of the country, where a third to a half of the population in the villages were infected. In addition, within each stratum, there is considerable heterogeneity observed between villages. The authors also reported interesting trends in the differential burden of asymptomatic and submicroscopic parasitemia, across the country varying by transmission intensity in the different regions. Notably the highest burden of disease, was among the older children (5-15 years) and participants with moderate and severe anaemia. However, sleeping under an Insecticide-Treated Mosquito Net (ITN) and being female reduced the odds of having parasitemia.

As indicators of the burden of malaria have substantially decreased in The Gambia, it is important to identify areas of on-going transmission across the country. These results suggest that despite a relatively high coverage of malaria control interventions in the country, they are not sufficient to interrupt transmission in the current context of modified human and vector behaviour and therefore, new approaches need to be urgently evaluated in order achieve elimination. These findings are relevant for malaria endemic countries that have been able to achieve significant reductions in malaria burden, as they provide information on the spectrum of residual disease that may persist in such settings.

Dr Mwesigwa said, “A better understanding of the dynamics of the human reservoir of malaria is key in providing information for development of new innovative tools aimed at eliminating malaria.”