Epidemiology of malaria and helminth interaction: a review from 2001 to 2011

Purpose of review Malaria and helminthiasis are endemic in the same geographic areas, and may coinfect the same host. In the literature there is some controversy about the effect of helminth infection on malaria. Recent findings Large studies have been undertaken to clarify this interaction at the molecular and immunological level, we undertake a review of the epidemiology of the interaction between helminths and malaria in areas where both are endemic. A search of the literature from 2001 to 2011 showed that several studies have been conducted on the interaction of helminths and malaria. Most of the studies had a cross-sectional or longitudinal design, whereas few were interventional studies of school children and pregnant women. The main finding is that there is a trend toward a protective effect of Ascaris lumbricoides and Schistosoma hematobium, and worsening effect of hookworm and S. mansoni on the pathogenesis and incidence of malaria, respectively. It is important also to put emphasis on the general protective effect of helminth infection against severe malaria. Summary Hookworm, A. lumbricoides and Schistosoma species were found to associate differently with malaria, which might explain the conflicting reports on interaction between helminths and malaria. It is therefore important to further investigate these three major helminths in relation to malaria, using universally accepted 'gold standard' study designs, which would be able to clearly define the nature of the interaction between malaria and helminth species. A better understanding of helminths and malaria coinfection may strengthen malaria control programmes in coendemic areas.