Occurrence of Leishmania spp. in phlebotomine sand flies and dogs in Guelma region, North-eastern Algeria.

Leishmania spp. are sand fly-borne parasitic protozoa of worldwide distribution that may severely affect the health and welfare of dogs as well as of other mammalian species, including humans. Algeria is among the most affected countries, counting several cases of Leishmania infantum infection in humans and dogs. Here, we assessed the occurrence of Leishmania species in both phlebotomine sand fly and dogs in the Guelma region, Northeast of Algeria. Sand flies were collected from July to September 2022, followed by a survey of canine leishmaniasis (CanL) from September 2023 to February 2024. Additionally, to understand the risk of human infection a retrospective data on cases of leishmaniasis recorded in the region from 2012 to 2023 were reported. Sand fly specimens and canine blood samples were tested by quantitative PCR (qPCR) for Leishmania spp., while dog serum samples were processed for anti-L. infantum antibodies detection by immunofluorescent antibody test (IFAT). Of the 1478 sand flies (n = 318 females; n = 1160 males), seven species were identified (i.e., Phlebotomus papatasi, Ph. perfiliewi, Ph. sergenti, Ph. perniciosus, Ph. longicuspis, Ph. ariasi, and Sergentomyia minuta). Leishmania spp. was detected in Ph. perniciosus, Ph. perfiliewi, Ph. papatasi, and Ph. sergenti (i.e., 3.7 %; n = 10). The overall seroprevalence rate was 58.2 %, with 1.6 % of dog blood samples positive for L. infantum at molecular screening. Multivariate analysis of the different risk factors revealed that CanL seropositivity was strongly related to dog age (> 1 year) (OR = 8.35, 95 % CI: 3.43-23.93), the autumn season (OR = 2.95, 95 % CI: 1.33-8.62), and lack of insecticide application (OR = 6.69, 95 % CI: 2.61-22.02). A total of 71 human cases of cutaneous (CL) and visceral (VL) leishmaniasis were recorded. Data presented reveal the occurrence of CanL in Guelma region, advocating for control program measures to be implemented in this part of Algeria.