Leishmania spp. infection in horses in an endemic area of canine leishmaniosis (north-western Algeria).

Leishmaniosis is a parasitic disease caused by obligate intracellular protozoa of the genus Leishmania. It affects humans, canids, and rodents in endemic areas and is transmitted through the bites of infected sand flies. This study aimed to estimate the prevalence of equine leishmaniosis in horses from Tiaret Province, northwestern Algeria, an area endemic for canine leishmaniosis, and to identify the main risk factors associated with infection. The study included 75 local Barb horses and employed molecular and serological techniques for the detection of Leishmania infection. Among the sampled animals, 71 tested positive by at least one diagnostic method, corresponding to an overall prevalence of 94.6%. Horses from the southern part of the province were 75% less likely to be infected than those from other areas (odds ratio [OR]: 0.259, 95% confidence interval [CI]: 0.067-1.004, p < 0.05). These findings provide the first evidence of equine leishmaniosis in northwestern Algeria. Furthermore, the exceptionally high prevalence observed in Tiaret Province suggests intense Leishmania transmission in the area, potentially posing a substantial risk of infection to other susceptible hosts, including humans and dogs. Consequently, the implementation of effective surveillance and control measures is essential to reduce the risk of transmission.