Serosurvey for Leishmania spp., Toxoplasma gondii, Trypanosoma cruzi and Neospora caninum in neighborhood dogs in Curitiba-Paraná, Brazil

Abstract Neighborhood dogs may act as reservoirs for several zoonotic protozoan infections, particularly in urban areas, thus constituting a potential public health threat. Accordingly, the aim of the present study was to evaluate the exposure of neighborhood dogs to four protozoan pathogens in public areas with high levels of human movement in Curitiba, southern Brazil. Blood samples from 26 neighborhood dogs were screened by means of the indirect immunofluorescent antibody test (IFAT) for Leishmania spp., Toxoplasma gondii, Trypanosoma cruzi and Neospora caninum, and a questionnaire was answered by the respective keeper. A total of 8/26 dogs (30.7%) seroreactive to T. gondii, 3/26 (11.5%) to N. caninum and 2/26 (7.7%) to both were identified. All the samples were seronegative for T. cruzi and Leishmania spp. Pathogen seroreactivity was not associated with the daily human movements or other epidemiological variables investigated (p > 0.05). In conclusion, the low seroprevalence for T. gondii and N. caninum indicated low environmental and food risk for animal infection and the seronegativity for Leishmania spp. and T. cruzi may reflect the absence of these pathogens in urban areas of Curitiba. Moreover, neighborhood dogs may be used as environmental sentinels for the presence of protozoan pathogens and their vectors.

摘要
社区犬只可作为多种人兽共患原虫感染的储存宿主，尤其在城市区域，因此构成潜在的公共卫生威胁。据此，本研究旨在评估巴西南部库里提巴市人员流动密集的公共区域内，社区犬只对四种原虫病原体的暴露情况。研究采集了26只社区犬只的血液样本，采用间接免疫荧光抗体试验（indirect immunofluorescent antibody test, IFAT）检测利什曼原虫属（Leishmania spp.）、刚地弓形虫（Toxoplasma gondii）、克氏锥虫（Trypanosoma cruzi）与犬新孢子虫（Neospora caninum）的血清抗体，并由犬只饲养者填写相关调查问卷。结果共检出8/26（30.7%）的犬只对刚地弓形虫呈血清反应阳性，3/26（11.5%）对犬新孢子虫呈血清反应阳性，另有2/26（7.7%）的犬只同时对两种病原体呈血清阳性。所有样本均未检测到克氏锥虫与利什曼原虫属的血清阳性反应。病原体血清反应性与每日人员流动量及其他调查的流行病学变量均无显著关联（p > 0.05）。综上，刚地弓形虫与犬新孢子虫的血清阳性率较低，提示动物感染的环境与食物传播风险较低；而利什曼原虫属与克氏锥虫的血清阴性结果，或反映库里提巴城市区域并无此类病原体存在。此外，社区犬只可作为原虫病原体及其传播媒介存在情况的环境哨兵。