Plasmodium mexicanum is, without a doubt, the best-studied species of lizard malaria parasite, and that is thanks to decades of work by Dr. Joseph Schall and his students. This parasite infects western fence lizards (Sceloporus occidentalis), in northern California and Oregon, but unlike most other Plasmodium species, it doesn't use a mosquito as its vector; it uses a phlebotomine sandfly. Work by Schall and others demonstrated that this parasite does have fitness consequences for its hosts - females lay fewer eggs and males have trouble defending a territory from other males. The parasite also seems to affect the bright coloring on the bellies of these lizards.
Photo by Schall himself.
Happy birthday, Joe.