Assessing the impact of preventative measures to limit the spread of Toxoplasma gondii in wild carnivores of Madagascar: A modeling study

Novel multi-host pathogens can threaten endangered wildlife species alongside impacts on human and domestic animals. The zoonotic protozoan parasite Toxoplasma gondii is transmitted by members of the Felidae family and can infect a large number of animal species, including humans. This parasite can cause significant health consequences to infected intermediate hosts and has the potential to further endanger the wild carnivoran populations of Madagascar. Building on an empirical characterization of the prevalence of the pathogen in local mammals, we use mathematical models of pathogen transmission in a multi-host community to compare different preventative measures that aim to limit the spread of this parasite in the wild carnivoran population. Specifically, we study the effect of hypothetical cat vaccination and population control campaigns on reducing the risk of infection by Toxoplasma gondii in wild Eupleridae. Our model predicts that the prevalence of exposure to Toxoplasma gondii in cats would be around 72%; while in rodents and wild carnivores, seroprevalence would reach 2% and 43% respectively. Reducing the rodent population in the landscape by half may only decrease the prevalence of T. gondii in carnivores by 10%. Similarly, cat vaccination and reducing the population of definitive hosts have limited impact on the prevalence of T. gondii in wild carnivorans of Madagascar and a significant reduction in prevalence would require extremely high vaccination and/or low turnover in cat population. Our study provides insights on potential control methods of T. gondii in endangered Eupleridae while highlighting the challenges of eliminating this threat entirely.