High rates of Leishmania infantum and Trypanosoma nabiasi infection in wild rabbits (Oryctolagus cuniculus) in sympatric and syntrophic conditions in an endemic canine leishmaniasis area: epidemiological consequences.

Leishmania infantum infection has been reported in various host species, both domestic and wild, in some cases with high prevalence rates. However, until the recent discovery of infected hares, no studies had provided clear evidence of any significant reservoir other than domestic dogs. Our focus was on another lagomorph, Oryctolagus cuniculus or wild rabbit. This species is native to the Iberian Peninsula and its presence and abundance gave rise to the name of Spain. In an endemic area for canine leishmaniasis in the southeast of Spain, 150 rabbits were captured over a period of three years. Samples of blood, bone marrow, liver, spleen, heart and skin were taken and analysed through parasitological, serological and molecular techniques in order to detect Leishmania and Trypanosoma. 20.7% of the rabbits were infected with L. infantum and 82.4% with Trypanosoma nabiasi, and 14.8% of mixed infections were detected. Both parasites were found in all the animal organs analysed, a factor which, along with the presence of serological cross-reactions, must be taken into account in epidemiological studies on leishmaniasis. O. cuniculus is an abundant and gregarious species, with a long enough average lifespan to ensure L. infantum transmission. The presence of the parasite in the skin and blood of these rabbits with no acute manifestation of disease ensures its contact with the vector, which finds in their warrens a suitable biotope to inhabit. The rabbit therefore seems to meet the most of conditions for being considered a reservoir host of L. infantum.