A computer simulation model for Strongyloides infection

Abstract

Despite high success rate in treating human Strongyloides infection with ivermectin, there is no consensus about the treatment of hyperinfection by helminths of the genus Strongyloides in immunocompromised people. Chances of survival of patients suffering from strongyloidiasis hyperinfection near 50%, with the toxicity of ivermectin in nervous system aggravating the puzzle. Creation of computer models capable of faithfully reproduce established knowledge about Strongyloides infection may be useful to understand the dynamics of infection and possible treatment. A computer model was developed in COPASI using ordinary differential equations representing dynamics of helminth life cycle in a hyperinfection. A combination of Boolean variables representing an 'immunosuppressed' host and 'treated' with four doses of ivermectin (200 µkg −1 ) raises four scenarios for time course simulations. Humoral and cellular immune responses were modeled using previous experiments whose data were approximated by ordinary functions. Three experiments, associated to strongyloidiasis hyperinfection, were successfully reproduced. A fourth scenario (immunosuppressed ∧ treated) yielded similar results compared to literature: four doses of ivermectin (200 µkg −1 ) were sufficient to restrain an infection, without a need for prolonged treatment. However, the smallest dosage does not suffice. A computational model for Strongyloides infection is available in SBML file format. The computational model here proposed for simulation of a hyperinfection by Strongyloides achieved similar results to previous experiments with hosts. It could allow us an in silico understanding of several aspects of infections caused by parasites of the genus Strongyloides.