Interventions can shift the thermal optimum for parasitic disease transmission

Temperature influences the transmission of many pathogens, but the effects of temperature variability on parasite and host traits and their interactive effects on transmission are poorly understood. We integrated an epidemiological model of schistosomiasis, an infectious disease that affects over 200 million people, with temperature-dependent traits of the causative parasite and its intermediate snail host. We show that simulated interventions targeting snails and parasite larvae increased the optimum temperature for transmission because intervention-related mortality overrode natural thermal constraints. We show that interventions are more effective at lower temperatures, climate change will increase schistosomiasis risk in regions where surface water temperatures move closer to the thermal optimum, and considering local climate conditions for disease control can maximize human health outcomes.