The blood parasites from the genus Hepatozoon Miller, 1908 (Apicomplexa: Adeleida: Hepatozoidae) represent the most common intracellular protozoan parasites found in snakes. In the present study, we examined 209 individuals of snakes, from different zoogeographical regions (Africa, America, Asia and Europe), for the occurrence of blood parasites using both molecular and microscopic examination methods, and assess phylogenetic relationships of all Hepatozoon parasites from snakes for the first time. In total, 178 blood smears obtained from 209 individuals, representing 40 species, were examined, from which Hepatozoon unicellular parasites were found in 26 samples (14·6% prevalence). Out of 180 samples tested by molecular method polymerase chain reaction (PCR), the presence of parasites was observed in 21 individuals (prevalence 11·6%): 14 snakes from Africa belonging to six genera (Dendroaspis, Dispholidus, Mehelya, Naja, Philothamnus and Python), five snakes from Asia from the genus Morelia and two snakes from America, from two genera (Coluber and Corallus). The intensity of infection varied from one to 1433 infected cells per 10 000 erythrocytes. Results of phylogenetic analyses (Bayesian and Maximum Likelihood) revealed the existence of five haplotypes divided into four main lineages. The present data also indicate neither geographical pattern of studied Hepatozoon sp., nor congruency in the host association.

We investigated the occurrence of blood parasites of two lizard species: the common or viviparous lizard (Zootoca vivipara) and the sand lizard (Lacerta agilis) in western Poland. Selected traits of lizard body morphology were studied with respect to the presence and intensity of haematozoan infection in blood samples collected from 218 adult lizards; 88 of the common lizard and 130 of the sand lizard. Haemogregarinid blood parasites were found to be the common parasite of both lizard species in studied locality with prevalence 39.8 (95% CL, 29.5-50.8) for Z. vivipara and 22.3 (95% CL, 15.5-30.4) for L. agilis. Incidence of parasitemia did not differ between sexes and was not correlated with morphological traits or presence of ectoparasites--Ixodes ricinus ticks. However, a significant difference between the two species of lizards was a greater frequency of haemogregarinid parasitism in Z. vivipara.