Molecular Prevalence of Leishmania infantum Infection from Oral Swabs Collected from Dogs in Region of Northwestern Spain

Leishmaniasis is a serious zoonotic parasitic disease caused by the protist <i>Leishmania infantum</i> and transmitted by phlebotomine sandflies in the countries of the Mediterranean basin. Dogs are the species most susceptible to the disease and serve as a reservoir for transmission to humans, making the Iberian Peninsula an endemic region for this infection. Although the regions close to the Mediterranean coast are the most prevalent regions of leishmaniasis in Spain, climatic factors are favouring the expansion of the vectors to more northern latitudes, where the disease was hardly known decades ago. This paper presents a prevalence study of <i>L. infantum</i> infection in the province of Zamora (northwestern Spain) using a non-invasive sample from canine buccal swabs and an innovative qPCR method to determine the etiologic agent. The parasite load of 151 randomly selected dogs from different points of the province was analysed during the period 2021-2022, with an estimated prevalence of 30%. In addition, the most common clinical signs of leishmaniasis in the dogs are described, and intrinsic factors associated with the nature of the dogs-such as sex, size, age as well as other factors related to the habitat in which they live and their geographical location-which could favour the disease, are evaluated.