The entomological inoculation rate and Plasmodium falciparum infection in African children

Once bitten...Ronald Ross won the 1902 Nobel prize for discovering the role of the mosquito in the parasite life cycle, but his later work on mathematical models for the study of its epidemiology was perhaps even more impressive. The Ross malaria model, still referred to, assumes that humans have an equal chance of a mosquito bite, and that infection clearance is unaltered by re-infection. We now know that some people are bitten more often than others, and that repeat infections slow parasite clearance. These and other new data have been incorporated in a mathematical framework to update the Ross model for the twenty-first century. Combined with data on over 90 communities infected by malaria, this reveals that variations in biting and/or susceptibility to infection are key factors determining the prevalence of infection: 20% of people receive 80% of all infections. This finding can be used to direct malaria controls at those most likely to benefit.