When should a trophically and vertically transmitted parasite manipulate its intermediate host? The case of Toxoplasma gondii

摘要: Parasites with complex life cycles are expected to manipulate the behaviour of their intermediate hosts (IHs), which increase predation rate and facilitate transmission definitive (DHs). This ability, however, is a double-edged sword when parasite can also be transmitted vertically in IH. In this situation, as manipulation IH increases death rate, it conflicts vertical transmission, requires healthy reproducing IHs. The protozoan Toxoplasma gondii, widespread pathogen, combines both trophic strategies. Is host still adaptive situation? We model evolution by T. gondii study conflict between these two routes under different epidemiological situations. Model outputs show that particularly advantageous for virulent strains epidemic situations, levels may evolve depending on sex considered. These results help understand variability strain characteristics encountered extend other trophically parasites.