Three Leishmania species identified in domestic dogs in Tunisia: New insights into canine leishmaniosis

BACKGROUND: Tunisia represents the perfect example of a Mediterranean Country where different Leishmania species may express their infectivity causing Visceral leishmaniasis by Leishmania (L.) infantum, Zoonotic Cutaneous Leishmaniasis by L. major and chronic cutaneous leishmaniasis by L. tropica. The recent detection of L. major in two dogs living in Tunisia confirms how this animal may host both visceral and cutaneous Leishmania species. The present study reports the results of 4 field surveys performed in central and southern districts of Tunisia: Zaghouan (ZA); Kairouan (2 surveys, K1 and K2); Tataouine (TA), to assess the prevalence of Leishmania species in dog. METHODS: One hundred and sixteen dogs were enrolled. Blood, lymph node and skin samples were collected with theowner' consent. Thirty-two were enrolled during 2021 in ZA (n = 32), fifty-four were enrolled in KA during 2022 (K1; n = 22) and 2024 (K2, n = 32) and thirty were enrolled in TA during 2024 (n = 30). All dogs correspond to new surveys other than those investigated in a previous study. In total 218 biological samples were analyzed by qPCR (kDNA), end-point PCR (ITS-1) and nested-PCR (SSUrRNA). The purified positive PCR products were sequenced. All dogs were classified as asymptomatic or with mild clinical signs, not specifically attributable to Canine Leishmaniosis due to the presence of fleas and tick infestation. RESULTS: Thirty-eight dogs tested positive by molecular techniques (32.75%%). Leishmania infantum was the most identified species (31/116, 26.72%). Extremely high prevalence was found in K2 (23/32, 71.87%) compared with the previous study K1 (10/22, 45.45%). One dog (K1) was positive to L. tropica, the first detection of this species in Tunisia, while two dogs (ZA and K2) confirmed the presence of L. major. Interestingly, we found for the first time a dog positive to L. infantum/donovani in TA, an arid area where no VL cases have been previously recorded. CONCLUSIONS: This study pointed out the high circulation of L. infantum in north and central Tunisia and underlines as the dog can host all the 3 Leishmania species present in this country.