BACKGROUND Dogs are the main peridomiciliary reservoir of Leishmania infantum thus the correct diagnosis of infection is essential for the control of the transmission and treatment as well. However, the diagnosis is based on serological assays that are not fully effective. OBJECTIVE We aimed to establish an effective serological assay for the diagnosis of L. infantum infected dogs using Leishmania-derived recombinant antigens. METHODS Leishmania derived rK39-, rK28-, rKR95-based enzyme-linked immunosorbent assay (ELISA) was standardized using symptomatic and asymptomatic L. infantum-infected dogs. Then 2,530 samples from inquiry in endemic areas for VL were evaluated and the results compared with recommended assays by the Brazilian Ministry of Health (MH algorithm). Further samples from a cohort of 30 dogs were searched. FINDINGS For rK39-, rK28- and rKR95-ELISA the sensitivity was around 97% and specificity 100%. The positivity of these three ELISA in the inquiry samples was 27-28%, around 10% higher than the assays currently in use. When cohort samples were searched, we observed likely false-negative results (> 65%) with supposedly negative samples that turned positive six months later with the assays in use (MH algorithm). MAIN CONCLUSIONS For the diagnosis of L. infantum-infected dogs, rK39-based ELISA showed better diagnostic performance than other assays in use in Brazil and worldwide.

Resumo O sucesso dos esforços para controlar uma doença zoonótica como a leishmaniose visceral (LV), causada por Leishmania infantum, depende de dados abrangentes sobre a infecção animal. Na Bahia, Brasil, embora a LV humana seja endêmica, diversos municípios, como Muritiba, ainda não dispõem de dados epidemiológicos sobre infecção por L. infantum e leishmaniose canina (LCan). Objetivou-se realizar um estudo epidemiológico para descrever a distribuição espacial e caracterizar a infecção canina por L. infantum em dois distritos de Muritiba, onde notificam-se casos humanos. Foi aplicado o protocolo sorodiagnóstico oficial brasileiro (ELISA e imunocromatografia), PCR e exame clínico em 351 cães domiciliados. Encontrou-se uma soroprevalência de 15,7% (55/351) e positividade de 88,8% (32/36) na PCR para L. infantum. A distribuição espacial dos cães positivos indicou infecção em ambos os distritos, urbano e rural. Não houve associação entre soropositividade e sexo ou raça, mas cães com idade acima de 2 anos foram 3,8 vezes mais soropositivos (IC 95% 1,57 - 9,18). Dentre os cães soropositivos, 80% (44/55) apresentavam manifestações clínicas de LCan: 75% (33/44) apresentavam dermatopatia; 50% (22/44) emagrecimento e 29,5% (13/44) oftalmopatia. Este é o primeiro estudo a determinar a soroprevalência e confirmar a circulação natural de L. infantum e LCan em cães de Muritiba.

Abstract Efforts to control a zoonotic disease such as visceral leishmaniasis (VL) caused by Leishmania infantum can be successful if they rely on comprehensive data on animal infection. In Bahia state, Brazil, human VL is endemic, yet some areas have no epidemiological data on canine L. infantum infection and canine leishmaniasis (CanL) to date. We aimed to perform an epidemiological study describing the spatial distribution and characterizing canine L. infantum infection in two districts of the municipality of Muritiba, where human cases have occurred. Brazilian official serodiagnostic protocol (ELISA and immunochromatographic tests), PCR and clinical examination were performed in 351 owned dogs. A seroprevalence of 15.7% (55/351) was found, and L. infantum identified in 88.8% (32/36) of PCR tested samples. Spatial distribution of positive dogs indicated infection in both urban and rural districts. There was no association between seropositivity and sex or breed, but dogs older than 2 years were 3.8 times more likely to be seropositive (95% CI 1.57 - 9.18) than younger dogs. Among seropositive dogs, 80% (44/55) had clinical manifestations of CanL: 75% (33/44) presented dermatopathy, 50% (22/44) emaciation, and 29.5% (13/44) ophthalmopathy. This is the first report on canine seroprevalence and natural L. infantum infection in Muritiba, Bahia.

RESUMO: O objetivo deste relato é descrever os achados clínico-patológicos, de imagem e o tratamento de colite por Pythium insidiosum em canino apresentando hematoquezia e emagrecimento progressivo. Nos exames de imagem, foram observados espessamento do cólon transverso e descendente. Análise histopatológica de fragmento do intestino grosso revelou a presença de hifas, confirmado pela imuno-histoquímica e PCR como P. insidiosum. Terapia antifúngica com itraconazol foi instituída pós-ressecção cirúrgica parcial, obtendo-se controle da doença.

ABSTRACT: The aim of this report is to describe the clinical, pathological and imaging findings and treatment of colitis caused by Pythium insidiosum in a canine presenting haematochezia and progressive weight loss. Through imaging, a thickening of the transverse and descending colon was observed. Histopathological analysis of the large intestine fragment revealed the presence of hyphae, confirmed by immunohistochemistry and PCR as P. insidiosum. Antifungal treatment with itraconazole implemented after partial surgical resection, resulted in control of the disease.

RESUMO: Este trabalho teve por objetivo comparar a detecção de DNA de Ehrlichia canis em amostras de sangue e medula óssea, além de determinar a ocorrência do agente em Várzea Grande, Mato Grosso. Amostras de sangue e medula óssea de 80 cães, de ambos os sexos, diferentes raças e idade, foram coletados em estudo seccional e processados para realização de nested PCR. Dos 80 cães, 61 (76,3%) apresentaram DNA de E. canis em uma das amostras pesquisadas. A capa leucocitária foi positiva em 42 (52,5%) e a medula óssea em 33 (41,3%). Não foi observada associação significativa com a positividade das amostras biológicas, sangue ou medula óssea, e a presença ou ausência de sinais clínicos (P=0,49). Nenhum fator de risco foi associado à infecção na área pesquisada. A amostra de medula óssea mostrou-se bom sítio para o diagnóstico molecular da erliquiose canina, principalmente quando da infecção com negatividade da amostra sanguínea.

ABSTRACT: The objective of this study was to compare the DNA detection of Ehrlichia canis in blood and bone marrow to determine the prevalence of the agent in Várzea Grande, Mato Grosso. Blood samples and bone marrow from 80 dogs of both sexes, different breeds and age, were collected and processed for a cross-sectional study performed using nested PCR. Of the 80 dogs, 61 (76.3%) had E. canis DNA in one of the samples. The buffy coat was positive in 42 dogs (52.5%) and the bone marrow was positive in 33 (41.3%). There was no significant association between the positive biological samples of either the buffy coat or bone marrow and the presence or absence of clinical signs (P=0.49). No risk factor was associated with infection in the studied area. The bone marrow samples were efficient for the molecular diagnosis of canine ehrlichiosis, particularly when there was a negative blood sample, although infection was present.