Leishmania (Sauroleishmania) tarentolae isolation and sympatric occurrence with Leishmania (Leishmania) infantum in geckoes, dogs and sand flies

Abstract

The trypanosomatid protist Leishmania tarentolae is a saurian-associated parasite vectored by the Sergentomyia minuta sand fly. This study aimed to confirm the circulation of L. infantum and L. tarentolae in sand flies, reptiles and dogs and to isolate new strains of these protists. Reptilian and sheltered dog blood samples were collected, and sand flies were captured. Samples were tested for Leishmania spp. using duplex real-time PCR (dqPCR) and real-time PCR (qPCR); the origin of blood meal was identified in engorged sand flies by conventional PCR. The reptilian blood and intestinal content of sand fly females were cultured. Dog sera were tested by IFAT using both Leishmania species. Four Tarentola mauritanica geckoes were molecularly positive for L. infantum or L. tarentolae, with no co-infections; moreover, amastigote-like forms of L. infantum were observed in the bone marrow. 24/294 sand flies scored positive for Leishmania spp. by dqPCR, 21 S. minuta and two Phlebotomus perniciosus were positive for L. tarentolae, while only a single Ph. perniciosus was positive for L. infantum. Blood meal analysis confirmed reptile and dog in S. minuta, dog and human in Ph. perniciosus and dog in Phlebotomus neglectus. Two axenic strains of L. tarentolae were obtained. Twelve of 19 dogs scored positive for L. infantum and L. tarentolae by IFAT and three of them also for L. infantum by dqPCR, and six by qPCR. These data confirm the sympatric circulation of L. infantum and L. tarentolae in geckoes, sand flies, and dogs, and suggest that geckoes may be infected with L. infantum.

Leishmania tarentolae : A new frontier in the epidemiology and control of the leishmaniases

“…Furthermore, L. infantum was molecularly detected in lizards in areas of canine leishmaniasis in southern Italy, in sympatric occurrence with L. tarentolae (Mendoza‐Roldan et al., 2022). The infection of L. infantum in reptiles was further corroborated through the retrieval of amastigote forms in the bone marrow of geckoes (Mendoza‐Roldan et al., 2022). These molecular findings suggest the interaction between both Leishmania species and ultimately raise the question who was infected first – reptiles by Leishmania or mammals by Sauroleishmania ?…”

“…Furthermore, additional attempts were made to identify and isolate Sauroleishmania from endemic areas of human and canine leishmaniasis. Axenic cultures of L. tarentolae were obtained from France (Gao et al., 2001) and Italy (Mendoza‐Roldan et al., 2022; Pozio, et al., 1983) with reports of L. tarentolae in different species of reptiles (Klatt et al., 2013; Klatt et al., 2019; Mendoza‐Roldan et al., 2022), sand flies (Mendoza‐Roldan et al., 2021) and mammals (Iatta et al., 2021) (Figure 4; Novo et al., 2015; Pombi et al., 2020; Annex 1). In particular, L. tarentolae is widely distributed and can infect saurian reptiles from the Gekkonidae (i.e., Mediodactylus kotschyi , Tarentola annularis , T. mauritanica ) and the Lacertidae (i.e., Podarcis filfolensis , Podarcis siculus ) families in the Mediterranean context (Figure 4; Annex 1) (Elwasila, 1988; Klatt et al., 2013; Mendoza‐Roldan et al., 2022; Pozio et al., 1983).…”

Leishmania tarentolae: a vaccine platform to target dendritic cells and a surrogate pathogen for next generation vaccine research in leishmaniases and viral infections

“…This led to the generation of BCG strains expressing antigens from other microorganisms, that have been assayed as candidate vaccines against a variety of pathogens unrelated with the mycobacteria [10]. Leishmania tarentolae, a parasite infecting reptiles, shares several features with BCG in terms of its potential to be exploited as a surrogate pathogen for use in vaccinations against leishmaniasis [11]. In addition, L. tarentolae has the potential to be developed as a vaccine platform of a wider interest, owing to the suitability of this parasite for genetic manipulation and, therefore, the production of heterologous protein antigens [11,12].…”

“…Although L. tarentolae, the type species of the subgenus Sauroleishmania [13], was described more than one century ago in the gecko Tarentola mauritanica [14], information on its natural history remains limited [11] with respect to other species within the subgenera Leishmania and Viannia. Indeed, the 21 species within the subgenus Sauroleishmania have historically been overlooked in leishmaniasis research, being associated with reptiles (from the families Agamidae, Gekkonidae, Lacertidae, Scincidae and Varanidae) and generally regarded to be non-infectious to mammals.…”

“…Information on transmission and development in mammals is limited canine leishmaniasis, but clinically healthy [48]. Therefore, in regions where L. tarentolae is highly prevalent in reptile and sand fly populations, the presence of this parasite may represent a factor capable of inhibiting the development of clinical forms of canine leishmaniasis, which is associated with antibody-mediated inflammatory reactions [11]. This possibility is further supported by the finding of Sergentomya minuta as the most abundant sand fly species in canine leishmaniasis endemic areas [31].…”