Reactivity of sera from dogs living in a leishmaniasis-endemic area to the COOH-terminal region of cysteine proteinase B

ABSTRACT Cysteine proteinases are well-known virulence factors of Leishmania spp. with demonstrated actions in both experimental mouse infection and human infection. However, studies on these enzymes in canine leishmaniasis are scarce. Here, we show, for the first time, the reactivity of sera from dogs living in an endemic area to a recombinant protein from the COOH-terminal region of cysteine B protease. In this work, enzyme-linked immunosorbent assays were performed using a 14 kDa rcyspep protein obtained through a pET28-a expression system in Escherichia coli. First, 96-well plates were coated with rcyspep (500 ng/well) and incubated with sera from dogs (1:100). Subsequently, IgG antibody detection was performed using rabbit anti-dog IgG antibodies conjugated with peroxidase. Sera from dogs (n = 114), including suspect (n = 30) and positive (n = 50) dogs from a leishmaniasis-endemic area and dogs from a nonendemic area, (n = 34), negative for leishmaniasis, were assessed. The results showed that sera from the suspect (42%) and positive (68%) groups responded differently to the antigen titers tested above the cut-off (Optical Density = 0.166). This finding suggests that the immune response detected against cyspep may be related to clinical disorders present in these animals. Collectively, the data gathered here suggest that cyspep can sensitize the immune systems of dogs from a leishmaniasis-endemic area to elicit a humoral response, an immunological parameter indicating the contribution of this protein in host-parasite interaction.

Epidemiological aspects of human and canine visceral leishmaniasis in Montes Claros, State of Minas Gerais, Brazil, between 2007 and 2009 / Aspectos epidemiológicos da leishmaniose visceral humana e canina em Montes Claros, Estado de Minas Gerais, Brasil, entre 2007 e 2009

INTRODUCTION: Visceral leishmaniasis (VL) is an expanding zoonosis in Brazil and is becoming urbanized in several Brazilian regions. This study aims to describe the epidemiological features of human and canine VL in the municipality of Montes Claros, State of Minas Gerais, by focusing on their spatial distribution. METHODS: Data concerning human cases and reactive dogs for VL from 2007 to 2009 were obtained from the Information System for Disease Notification (SINAN) and from reports of the local Centro de Controle de Zoonoses (CCZ), respectively. The addresses of human and canine cases have been georeferenced and localized in thematic maps, allowing their spatial visualization as well as the identification of areas at risk of VL transmission. RESULTS: Ninety-five cases of human VL were reported in the period. The 0-9-year-old age group (48.4 percent) was the most affected, within which the majority consisted of male patients (64 percent). Of the samples collected for the canine serological survey, 2,919 (6.3 percent) were reactive to VL. The spatial localization of these cases shows that the disease was scattered in the urban area of the municipality. Areas showing a higher dissemination risk were concentrated in the central, northwestern, and southern regions of the city. CONCLUSIONS: Identifying the areas most at risk in urban Montes Claros may help guide actions toward local epidemiological vigilance and control.

INTRODUÇÃO: A leishmaniose visceral (LV) é uma zoonose em expansão no Brasil e está se tornando urbana em várias regiões brasileiras. Este estudo descreve aspectos epidemiológicos da LV humana e canina no município de Montes Claros, Minas Gerais, com enfoque na distribuição espacial de sua incidência. MÉTODOS: É um estudo epidemiológico descritivo, que utiliza dados relativos à casos humanos e soro-positividade canina para LV, obtidos do Sistema de Informação de Agravos de Notificação (SINAN) e de relatórios do Centro de Controle de Zoonoses (CCZ) local. Os endereços dos casos estudados foram georreferenciados e localizados em mapas temáticos que permitem sua visualização espacial, bem como a identificação de áreas de risco de transmissão da doença. RESULTADOS: A leishmaniose visceral humana e canina mostrou ampla distribuição espacial em Montes Claros. No período entre 2007 a 2009, foram notificados 95 casos humanos da doença. O grupo etário entre 0 e 9 anos foi o mais afetado (48.4 por cento) com maior prevalência no sexo masculino (64 por cento). Dentre as amostras caninas coletadas para investigação sorológica, 2.919 (6,3 por cento) foram reativas para LV. A localização espacial desses casos mostra que a doença está disseminada na área urbana do município. As áreas com maior risco de disseminação concentraram-se nas regiões central, noroeste e sul da cidade. CONCLUSÕES: A identificação das áreas de maior risco na zona urbana de Montes Claros poderá guiar as ações de vigilância epidemiológica e de controle locais.