COMPUTER SIMULATION OF A MALARIA CONTROL TRIAL IN VANUATU USING A MATHEMATICAL MODEL WITH VARIABLE VECTORIAL CAPACITY

抄録

We have developed a mathematical model to estimate the degree of transmission of Plasmodium falciparum malaria, that is adjusted to an endemic region in Vanuatu, eastern Melanesia, incorporating the factor concerning the loss of immunity in human hosts. Applying this model, we have carried out simulations for more than fifty situations. Our model is based on Dietz et al. (DMT) model which contains epidemiological factors related to malaria transmission. By using field data from an epidemiological study in Vanuatu, we have determined epidemiological parameters and improved the model. Also our model can treat situations with variable vectorial capacity value. The simulations carried out show that it is important to decrease vectorial capacity by taking anti-malarial measures in order to reduce the prevalence of malaria. One or two operations of mass drug administration will reduce Plasmodium falciparum prevalence drastically, but intense reinfection will raise infection rate again within a few years. However, the resurgence of malaria will not occur for a long time if mass drug administration accompanied with possible reduction of vectorial capacity by vector control such as insecticide impregnated bed nets and others.