Canine Leishmaniasis in Rio de Janeiro, Brazil (2000-2015): Taxonomic Characterisation of Etiological Agents and...

Canine Leishmaniasis is a vector-borne zoonotic disease caused by several species of protozoa of the genus Leishmania. In the state of Rio de Janeiro (RJ), Leishmania braziliensis is the most prevalent species causing tegumentary leishmaniasis (TL) and Leishmania infantum is the main causative agent of visceral leishmaniasis (VL). Dogs are the main reservoirs of L. infantum and can be infected with other Leishmania species; however, their role as a reservoir for these species is still poorly understood. There are few epidemiological studies characterising Leishmania at the species level in isolates from dogs in the state of RJ and analysing their geospatial distribution.

This work aimed to perform the taxonomic characterisation of Leishmania isolates, obtained from 565 dogs diagnosed between 2000 and 2015 in a reference centre for infectious diseases in RJ, Brazil. Dogs with a positive parasitological diagnosis by in vitro culture of different biological samples (intact skin, skin lesion, bone marrow, spleen, lymph node and others) were included. The characterisation of Leishmania species was carried out using multilocus enzyme electrophoresis technique. The dogs' home addresses were individually georeferenced. Thematic and heat maps were created in the QGIS software with cases and the distribution of characterised species.

The dogs clinically evaluated (n = 236) were classified as asymptomatic (n = 93; 39.4%), oligosymptomatic (n = 92; 39%), or polysymptomatic (n = 51; 21.6%). A total of 518 Leishmania isolates from dogs were characterised by MLEE as L. infantum (n = 456; 88%) and L. braziliensis (n = 62; 12%), which were obtained by cultivating biological samples from different canine sites. Heat maps identified Barra Mansa as an area of intense VL transmission and Rio de Janeiro and Maricá as municipalities with intense TL transmission.

This study contributed to the knowledge of the taxonomic characterisation and geospatial distribution of Leishmania species responsible for canine leishmaniasis in the state of RJ, considering the case series from a reference centre for the diagnosis of leishmaniasis in the state of RJ, Brazil.