Section: New Results

Analysis and observer design for a schistosomiasis model

Human schistosomiasis is a behavioral and occupational disease associated with poor human hygiene, insanitary animal husbandry and economic activities. Among human parasitic diseases, schistosomiasis ranks second behind malaria as far as the socio-economic and public health importance in tropical and subtropical areas are concerned. The spread and persistence of schistosomiasis have made of it one of the most complex host-parasite process to model mathematically because of the different steps of growth of larvae assumed by the parasite and the requirement of two host elements (definitive human host and intermediate snail hosts) during their life cycle.

An efficient method to control the schistosomiasis infection that may require relatively little funding is a biological control. Particularly, trematode parasites or competitive snails of the intermediate snail hosts have been proved to be effective in controlling schistosomiasis in the Caribbean area.

We have studied a schistosomiasis infection model that involves human and intermediate snail hosts as well as an additional mammalian host and a competitor snail species. This mathematical analysis of the model gives insight about the epidemiological consequences of the introduction of a competitor resistant snail species [15] .

We have also proposed a solution to the state estimation problem for a schistosomiasis infection dynamical model described by a continuous non linear system when only the infected human population is measured. We have constructed an estimator that is able to give dynamical estimates of the variables that can not be measured [14] .