Double gametocyte infections in apicomplexan parasites of birds and reptiles

The simultaneous occurrence of male and female gametocytes inside a single host blood cell has been suggested to enhance apicomplexan transmission ["double gametocyte infection (DGI) hypothesis"]. We did a bibliographic search and a direct screen of blood smears from wild birds and reptiles to answer, for the first time, how common are these infections in the wild. Taking these two approaches together, we report here cases of DGIs in Plasmodium, Haemoproteus, Leucocytozoon and Hepatozoon, and cases of male-female DGIs in Haemoproteus of birds and reptiles and in Leucocytozoon of birds. Thus, we suggest that DGIs and male female DGIs are more widespread than previously thought, opening a new research avenue on apicomplexan transmission.