Pathogenic Leishmania spp. detected in lizards from Northwest China using molecular methods.

Background: Leishmaniosis, a disease caused by pathogenic Leishmania parasites, remains an unresolved health problem in the New World and the Old World. It is well known that lizards can be infected by a subgenus of Leishmania parasites, i.e. Sauroleishmania, which is non-pathogenic to humans. However, evidence suggests that lizards may also harbor pathogenic Leishmania species including the undetermined Leishmania sp., discovered in our previous work. Leishmania DNA in lizard blood can be detected by using molecular methods, such as the polymerase chain reaction (PCR).

Results: Three hundred and sixteen lizards, representing 13 species of four genera, were captured for blood samples collection in Northwest China. Two reliable molecular markers (cytochrome b and heat shock protein 70 genes) were used for detection in the lizard blood samples, to confirm a widespread presence of pathogenic Leishmania parasites and the distribution pattern of Leishmania spp. in lizards from Northwest China. The PCR data indicated positive detection rate for Leishmania in all the tested lizards with an overall prevalence of 57.91% (183/316). Apart from lizard parasites like Leishmania tarentolae and Leishmania sp., several pathogenic Leishmania including L. turanica, L. tropica and L. donovani complex were identified by using phylogenetic analysis. Co-existence of different haplotypes was observed in most Leishmania DNA-positive lizards with an overall rate of 77.6% (142/183). Even mixed infections with different Leishmania species appeared to occur in the lizards with an overall rate of 37.7% (69/183).

Conclusions: Lizards can harbor pathogenic Leishmania spp. Co-existence of different haplotypes or even species of Leishmania indicates mixed infections in natural lizard host. Lizards may contribute to the spread of Leishmania parasites. The pathogenic Leishmania species detected in lizards from Northwest China may be of great eco-epidemiological importance.