Abstract
The dynamics of vector-borne diseases are driven by interactions between factors intrinsic to the parasite, its host, and environmental fluctuations. Understanding these interactions requires a long-term view, especially to predict the consequences of climate change on parasite dynamics. We examined temporal fluctuations in risk of infection, its environmental drivers and consequences for host body condition of three malaria parasites (Plasmodium azurophilum, P. leucocytica, and P. floridense) infecting the lizard, Anolis gundlachi, in the rainforest of Puerto Rico. Our analyses included 13 surveys totaling > 8000 lizards over 26 years. During the early years of the study, prevalence of all three Plasmodium species appeared stable despite disturbances from short droughts and hurricanes. Taking the longer view, we found that the risk of infection and overall prevalence vary significantly over the years, and this fluctuation was driven in non-linear ways by variations in temperature and rainfall. We also found that risk of infection was maximized at intermediate levels of temperature and precipitation; relative proportions of the three Plasmodium species changed over time; and no significant negative effects of parasite infection on the lizard's body condition. Overall, the results emphasize the need for long-term studies to reveal host-parasite dynamics, their drivers and consequences.