Canine leishmaniosis (CanL) is a chronic, systemic, and often severe disease. The main
causative agent of CanL is a protozoan parasite, Leishmania infantum, with phlebotomine sand flies
acting as vectors. In Europe and other continents, L. infantum is also responsible for leishmaniosis
in other animals, such as cats, horses, and humans. In Portugal, animal and human leishmaniosis
is endemic, and high prevalence levels of infections and disease have been reported in dogs. There
is a prejudice against stray animals and also those housed in shelters, assuming they have higher
levels of infection with vector-borne pathogens, including L. infantum, when compared to domestic
animals. In northeastern Portugal, serum samples were obtained from March to May 2022 in three
shelters (n = 179) and thirteen veterinary clinics (n = 164), resulting in 343 dogs being analyzed for
antibodies to Leishmania spp. by the direct agglutination test (DAT). The overall seroprevalence was
9.9%, with 15.2% seroprevalence in domestic dogs and 5.0% in the shelter ones (p = 0.003). The fact
that shelter dogs had a lower seroprevalence could be explained by more regular veterinary care
provided in shelters regarding preventive measures, including insecticides with an antifeeding effect,
in comparison with domestic dogs.
