Elucidating a wildlife disease: Do lizards get malaria?

Malaria, most people are surprised to learn, was originally a reptile disease: the majority of the Plasmodium species known to science infect reptiles. Early research in the lab investigated the effects of the lizard malaria Plasmodium chiricahuae on its host, the Mountain Spiny Lizard (Sceloporus jarrovi) found in the mountains of SE Arizona. Perhaps surprisingly, this species of malaria is not transmitted by mosquitoes as many mammal malarias but rather through a tiny sand fly that lands and attaches itself to a lizard to obtain a blood meal. A combination of observational studies and experimental manipulations revealed that infected lizards - although superficially appearing to be healthy - experience significant impacts of infection in the form of increased mortality, especially in old age, as well as stunted growth (in females only). Because infected females also lay fewer eggs than healthy ones, occurrence of malaria can result in population-wide declines of host reproduction (see Foufopoulos, 1999).