Morphometric and molecular characterisation ofHepatozoon bashtarin. sp. in painted saw-scaled viper,Echis coloratus(Ophidia, Viperidae)

Hepatozoonspecies are the most widely known haemogregarines infecting a wide range of vertebrates, although predominately snakes. Herein,Hepatozoon bashtarin. sp., originally infecting the painted saw-scaled viper,Echis coloratus, in Saudi Arabia is described using both morphological features and molecular data from 18S rDNA sequences. The overall prevalence of infection was 60% (9/15) with parasitaemia ranging from 52 to 60%. Gamonts were entirely intraerythrocytic and were observed to cause considerable hypertrophy within the host cell. The mean size of mature gamonts was 15.4 x 3.3 mu m. Merogonic stages were confined to the lung endothelial cells with monomorphic meronts. The average size of mature meronts was 32 x 12 mu m and they were estimated to produce 13-16 merozoites each. The phylogenetic tree generated from SSU rDNA sequences revealed thatHepatozoon bashtarisp. n. clusters with the vast majority of otherHepatozoonspecies infecting snakes, lizards and geckos in various regions of the world, which would appear to support the hypothesis of prey-predator transmission of the genusHepatozoon. Through a combination of morphological comparison with closely relatedHepatozoonspp. and 18S rRNA gene sequence analysis, it is possible to confirmHepatozoon bashtarisp. n. as a new species.