Unveiling Sauroleishmania in southern Africa: An investigation and supplementary description of Leishmania (Sauroleishmania) zuckermani from the gecko host Chondrodactylus bibronii.

Parasites of the genus Leishmania (Kinetoplastida: Trypanosomatidae) are the etiological agents of leishmaniases, neglected tropical diseases that affect both humans and animals worldwide, ranking second only to malaria in terms of parasite-related human fatalities. In southern Africa, few cases have been reported, and data on the epidemiology and etiology of leishmaniases remain scarce. Moreover, almost nothing is known about the circulation of reptile-infecting Leishmania parasites of the subgenus Sauroleishmania in the region. These parasites are generally regarded as non-pathogenic to mammals, and one species, Leishmania (Sauroleishmania) tarentolae, is reported to elicit a protective immune response against pathogenic Leishmania species in mammals upon exposure. Nevertheless, Leishmania (Sauroleishmania) adleri is known to have caused infections in rodents and humans. Another significant knowledge gap in southern Africa concerns sand flies, vectors of Leishmania parasites, recorded only from occasional, small-scale surveys conducted primarily in South Africa. In the present study, to address this gap, sand flies and Bibron's thick-toed geckos (Chondrodactylus bibronii) were sampled and investigated within Bankfontein in the Free State province. We provide the first report of sand flies in the Free State, and, for the first time in South Africa, we molecularly characterized a species of Sauroleishmania with the supplementary description of Leishmania (Sauroleishmania) zuckermani, which has not been reported since its original description in 2001. The present study found an apparently low prevalence of the parasite, with two infected individuals of 40 geckoes screened over a three-year timeframe. One infected host was captively monitored and remained infected with the parasite for at least 415 days. Phylogenetic analysis recovered L. (S.) zuckermani as the sister clade of L. (S.) adleri. These findings highlight the need for further investigations into the diversity, distribution, and potential zoonotic risk of Sauroleishmania in southern Africa, alongside the need for more comprehensive sand flies' surveys.