Detection and molecular characterization of Leishmania in dogs from northeastern Brazil

OBJECTIVE: The aim of the present study was to determine the current seroprevalence of canine leishmaniasis (CanL) among domiciled dogs, factors associated with seropositivity, circulating Leishmania species and spatial analysis, in six municipalities in the Sertão and São Francisco mesoregions, which are located in the state of Pernambuco, Brazil. METHODS: Blood samples from 330 dogs were analyzed using serological and molecular assays: dual path platform (DPP®); enzyme-linked immunosorbent assay (ELISA), indirect fluorescent antibody test (IFAT) and polymerase chain reaction (PCR). The nucleotide sequences of four gene markers (kDNA, cathepsin L-like, SSU-rDNA and gGAPDH) were explored to perform a phylogenetic analysis. RESULTS: The overall seroprevalence was 13% (43/330) in dogs that were simultaneously positive according to DPP® ELISA and IFAT, consisting of 13.9% (23/165) in Sertão and 12.1% (20/165) in São Francisco. The factors associated with high prevalence of L. infantum antibodies in dogs comprised living in the municipality of Petrolina (P = 0.045) and presenting ocular lesions (P = 0.049) (P ≤ 0.05). Significant clusters of positive dogs were found in rural areas. The positivity values obtained through PCR based on the genes kDNA and cathepsin L-like were 6.7% (22/330) and 2.4% (8/330), respectively. In the phylogenetic analysis, it was observed that all the isolates obtained showed 100% similarity to Leishmania infantum. CONCLUSION: For the first time, L. infantum was confirmed as the etiological agent of CanL in this region. Thus, assessment of the genetic structure of populations of Leishmania spp. is important for understanding the patterns for transmission of CanL.