Etiology, Geographic Distribution and Transmission
Diseases caused by Leishmania spp. in cats are far less known than in dogs and humans, and felines had been considered to be less susceptible than dogs to Leishmania infection in the past. However, a high number of investigations confirmed in the last decades the susceptibility of cats to Leishmania infection, and that they are infectious to sand fly vectors. Additionally, case reports have increasingly been reported, but controlled field studies about clinical management and therapy are still lacking.
From the above considerations it follows that feline leishmaniosis (FeL) is a topic of interest for feline medicine and that cats play a role in the One Heath approach of leishmaniosis.
Etiology, Geographic Distribution and Transmission
Cats are potentially infected by the same Leishmania spp. that infect dogs and humans in endemic areas all over the world (Figure 1). Leishmania infantum is the most frequently reported species infecting cats, and this fact sheet is based on published data on L. infantum infection and the associated feline disease, mostly reported in the Mediterranean Basin and Middle East region. However, this species is largely described in cats also in Central and South America.
Leishmania infantum is transmitted to cats by sand flies, as they have been shown to feed on cats and to be infected after feeding on naturally infected cats. Moreover, sand flies infected from cats transmitted the infection to dogs. Considering that infected cats are a source of infection to sand flies and generally suffer from chronic infection, LeishVet postulates that, based on new insights in the epidemiology of leishmaniosis, infected cats can represent an additional domestic reservoir for L. infantum to humans, dogs, and other susceptible hosts, including cats themselves. However, there is some evidence that cats are likely less infectious to sand flies than dogs.
Non-vectorial transmission of L. infantum (blood transfusion, vertical transmission, mating, aggressive interactions) is documented in dogs but not yet in cats. However, Leishmania DNA has been detected by PCR in the blood of some healthy cats (see “Diagnosis” and “Prevention” sections).