Erythrocytic viral infections of lizards and frogs: new hosts, geographical locations and description of the infection process

Pirhemocyton infections are reported from erythrocytes of six species of gecko from Australia, one each from France and Cisjordan, and from two Agama spp. and one skink from Africa. Toddia is reported from a Thai and a South African frog. Infection in all geckoes involved the formation of a vacuole in the erythrocyte. This vacuole was lacking in infections of agamids and skinks. In was also lacking in Toddia infections, but in these, there was a formation of a crystalloid body. Viral inclusions were largest in immature erythrocytes, and were larger in Toddia than in Pirhemocyton. Pathological changes in the infected erythrocytes and the course of infection in lizards and frogs are reported and discussed. Infected cells gradually degenerate either by shrinkage or through vacuolation. Loss of the infected cell was compensated for by proliferative hematopoiesis. Critical hematological conditions develop when many or all erythrocytes became infected. Accelerated hematopoiesis led to recovery, whereby the infection regressed and infected erythrocytes were replaced by new, uninfected ones. Infection was either eliminated, or latent at a low level, with the potential to cause later relapse.