Transmission of visceral leishmaniasis in dogs in a risk area of the metropolitan region of Belo Horizonte, Minas Gerais, Brazil / Transmissão da leishmaniose visceral em cães em área de risco da Região Metropolitana de Belo Horizonte, Minas Gerais, Brasil

Visceral leishmaniasis (VL) has spread rapidly across cities in the metropolitan region of Belo Horizonte. The aim of this study was to investigate VL dynamics in a prospective cohort study of dogs in Juatuba, between 2010 and 2011, to confirm the incidence of Leishmania infantum, and to assess possible risk factors associated with infection. An observational and prospective closed cohort study was performed using serology testing in dogs, randomly selected from the whole municipality. All seronegative dogs, or dogs with inconclusive results were monitored using indirect immunofluorescence (IIF) at 6-month intervals. The dog's owners completed a semi-structured questionnaire to assess possible causal factors of seroconversion, and the responses were assessed using logistic regression. The canine incidence coefficient was 206/1,000 dogs per year (CI: 178-238), and a cluster was identified in an area with a high concentration of seropositive dogs, but a low overall canine population. Large dogs were identified as a risk factor and the following variables were identified as protection factors: dogs aged over 4 years, daily peridomicile cleaning, and better socioeconomic conditions. VL is spreading over a large area in Juatuba in a short period of time.(AU)

A leishmaniose visceral (LV) expandiu-se de forma rápida e extensa pelos municípios da Região Metropolitana de Belo Horizonte. Objetivou-se estudar a dinâmica da LV em uma coorte prospectiva de cães em Juatuba, entre 2010 e 2011, para verificar a incidência e fatores de risco associados à infecção por Leishmania infantum. Foi feito um estudo observacional e prospectivo de coorte fechada por meio de análise sorológica em cães selecionados aleatoriamente em todo o município, com acompanhamento semestral dos resultados soronegativos e indeterminados na imunofluorescência indireta (IFI). Usou-se questionário semiestruturado junto aos proprietários de cães para avaliação da soroconversão e dos fatores determinantes a essa, por meio da regressão logística. O coeficiente de incidência canina foi de 206/1000 cães.ano (IC: 178 - 238), e foi identificado cluster em área com elevada concentração de cães soropositivos, mas com baixa densidade populacional canina. A variável cão de porte grande foi identificada como fator de risco, e as variáveis idade do cão superior a quatro anos, limpeza diária do peridomicílio e melhores condições socioeconômicas como fatores de proteção. A infecção por LV está ocorrendo em curto período de tempo e com ampla distribuição em Juatuba.(AU)

Flow cytometric assay in peripheral blood of dogs--reference values for leukocytes from Brazilian beagles.

Use of domestic reference values in the flow cytometry analysis is known to improve its accuracy by integrating local variations as gender, race and age. Up to date application of flow cytometry in veterinary medicine has been limited to describe the percentual values just for peripheral lymphocytes subsets of blood. We now report establishment of reference values for a wide range of proportional and absolute numbers of peripheral blood leukocytes, including T cells subsets, B cells, monocytes and eosinophils, applicable to the healthy population of Beagles in Brazil and other regions with similar demographic characteristics. Normal reference values were also established to estimate the gender-related differences. This information will provide clinical aid in the evaluation of immunologic status as well as standard values for experimental animals of dogs from Brazil and other similar regions.

Impact of canine control on the epidemiology of canine and human visceral leishmaniasis in Brazil.

Brazil is the only country endemic for zoonotic visceral leishmaniasis (ZVL) that regularly conducts epidemiologic and prophylactic control programs that involve the treatment of human cases, insect vector control, and the removal of seropositive infected dogs. This report reviews 60 studies reporting data on the efficacy of these recommended control tools and concludes that in Brazil 1) eradication of the disease in Minas Gerais was achieved by the concomitant use of the three control methods, 2) although seropositivity by an immunofluorescent assay is not completely related to infectiousness, the removal of seropositive dogs leads to a significant reduction of canine and human incidence, 3) improvement of the sensitivity of the diagnostic tool used for canine control should optimize the efficacy of control, and 4) although difficult and expensive, the public health dog control campaigns performed in Brazil reduced the incidence of ZVL and should be maintained since treatment of dogs is an unrealistic intervention, both because of its prohibitive cost and relatively poor effectiveness.

Histopathology and immunocytochemical study of type 3 and type 4 complement receptors in the liver and spleen of dogs naturally and experimentally infected with Leishmania (Leishmania) chagasi.

The objective of this study was to compare the histopathological changes and expression of CR3 and CR4 in the liver and spleen of dogs naturally and experimentally infected with L. chagasi. The basic histopathological lesions observed mainly in naturally infected dogs were: epithelioid hepatic granulomas, hyperplasia and hypertrophy of Kupffer cells, Malpigui follicles and mononucleated cells of the red pulp of the spleen. Sections from the liver and spleen by immunocytochemistry technique showed the presence of CD11b, c/CD 18 antigens in the control and infected animals and no qualitative or quantitative differences in the liver. Nevertheless, CD18 was always increased in the spleen of naturally and experimentally infected dogs. These results indicate that there is a difference in the activation of CD18 in both experimental and natural cases of canine visceral leishmaniasis that should play an important role in the immunological response to Leishmania chagasi infection.