The present study aimed to evaluate factors associated with canine visceral leishmaniasis (CVL) in areas with higher seroprevalence of it in Uruguaiana city, Rio Grande do Sul state, Brazil, during the year of 2012. A semi-structured questionnaire with socioeconomic and environmental questions was applied in Leishmania endemic regions of the city. The survey data were analyzed by multivariate statistics and the associations between them were presented as odds ratio within a 95% confidence limit. The relationships between the studied variables showed no statistically significant difference between the dwellings with positive and negative dogs. However, when analyzing the odds ratio, the presence of green areas larger than 10m² turned the house into an area of potential risk for CVL (OR= 2.53). There was no difference among the socioeconomic variables education and income, though the groups with lower education and income showed a higher seroprevalence of CVL. The city of Uruguaiana is already located within the CVL broadcasting area and is taken as an endemic region of the disease, with seropositive dogs in all neighborhoods. Thus, the determinants for an increased Leishmania sp. infection could not be indicated, even so, the maintenance of green areas around the households represented a risk factor for being a potential vector shelter. Key words: Neglected disease. Epidemiology. Environment. Socioeconomic factors. ResumoO objetivo da presente pesquisa foi avaliar potenciais fatores de risco associados à ocorrência de leishmaniose visceral canina (LVC) em áreas de maior prevalência no município de Uruguaiana/RS, no ano de 2012. Foram aplicados questionários semiestruturados com questões socioeconômicas e ambientais em bairros endêmicos para LVC no município de Uruguaiana. Os dados foram analisados por meio de análise multivariada e as associações entre as variáveis foram expressas em odds ratio com intervalos de confiança de 95%. As relações entre as variáveis estudadas não apresentaram diferença estatística significativa quando se comparou residências com cães positivos àquelas com cães negativos. Entretanto, a presença de área verde maior que 10m² apresentou-se como um potencial fator de risco (OR= 2,53) para LVC. Não houve diferença significativa entre as variáveis socioeconômicas, escolaridade e renda embora, nos grupos de menor escolaridade e de menor renda familiar, tenha havido
Leishmaniasis is a neglected zoonotic disease caused by a variety of pathogenic Leishmania species. In the New World, especially in Brazil, visceral leishmaniasis (VL) is caused by Leishmania infantum. The pathogen can infect several animal species including dogs, foxes, rodents, primates, felines, equines and humans. Dogs act as the primary domestic reservoirs. This study aimed to use polymerase chain reaction (PCR) for detecting Leishmania infection in horses living in a canine visceral leishmaniasis (CVL) endemic region. DNA samples from horse peripheral blood were used to perform PCR. Templates were amplified using primers for the kinetoplast DNA (kDNA) minicircles, which were able to detect different species of Leishmania. In addition, primers for internal transcribed spacer (ITS) of ribosomal DNA were used for detection of Trypanosomatidae sp. Amongst the 75 (39%) positive PCR samples from total 192 samples, 21 samples were positive for kDNA and 63 samples were positive for either ITS, ITS1, or ITS2 gene markers. The kDNA PCR and sequencing allowed the detection of L. infantum in horse blood samples. To our knowledge, this is the first report of equine infection with L. infantum in Southern Brazil. These results proved that L. infantum could also infect horses in addition to humans and dogs, as well as in European countries. This conclusion emphasizes the urgent need to follow up investigation of the infection in these animals.
Visceral leishmaniasis is an endemic zoonotic disease identified especially in developing territories. Brazil's northeast, southeast and midwest have been endemic for several years; currently, the infection is spreading to the south. Dogs are the main reservoirs; however, other mammal species have also been infected. Herein, we have identified the infecting Leishmania species in dogs and horses from the south of Brazil, a new outbreak of the infection. Blood samples were collected in the urban area of Uruguaiana city. DNA was extracted from peripheral blood, kinetoplast DNA (kDNA) and ribosomal DNA (rDNA) fragments were obtained by polymerase chain reaction (PCR) and sequenced. Out of 123 samples, 25 of them (14 dogs and 11 horses) were positive for Leishmania spp. Sequence alignment and phylogenetic analysis revealed that the kDNA in positive samples was similar to four species previously reported: L. infantum/L. chagasi, L. donovani, L. major. Despite kDNA minicircles regions are very useful due to high sensitivity to Leishmania spp. DNA detection, the sequence polymorphism among minicircles can be an obstacle to interspecific differentiation. Our results suggest that these strains are circulating in Brazil south region cross‐border and indicate the susceptibility of new outbreak for visceral leishmaniasis infection in horses domiciled in endemic region for canine and human visceral leishmaniasis.
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