A cross-sectional approach including dog owner characteristics as predictors of visceral leishmaniasis infection in dogs

BACKGROUND Visceral leishmaniasis (VL) is relevant for human and animal public health. Several factors have been associated with the risk of Leishmania infantum infection in dogs. However, dog owner characteristics have been rarely explored. OBJECTIVES To estimate the prevalence and to identify the associated factors for VL infection including dog owners characteristics. METHODS A cross-sectional study was conducted including dogs from an endemic canine visceral leishmaniasis (CVL) region in the Federal District, Brazil. The infection was detected using parasitological, serological, and molecular methods. The associated factors were identified through Poisson regression modelling. FINDINGS The prevalence of infection was 26.25% [95% confidence interval (CI): 20.05 to 33.57]. The associated factors were: short coat prevalence ratio (PR) = 2.33 (95% CI: 1.02 to 5.22); presence of backyard with predominance of soil and/or vegetation PR = 4.15 (95% CI: 1.35 to 12.77); and highest gross family income score PR = 2.03 (95% CI: 1.16 to 3.54). MAIN CONCLUSION This is the first study that relates higher socioeconomic status of dog owners as an independent factor associated with higher prevalence of VL infection, along with other strongly associated factors related to receptive environment for phlebotomines. Our findings strengthen the need for exploration of the biological and behavioural bases linking dog owner characteristics to the risk of canine infection in prospective cohort studies.

背景 内脏利什曼病（Visceral leishmaniasis, VL）对人类与动物公共卫生均具有重要意义。目前已有多项因素被证实与犬感染婴儿利什曼原虫（Leishmania infantum）的风险相关，但针对犬主人特征的相关研究却极为少见。
研究目的 本研究旨在估算VL感染的流行率，并明确包括犬主人特征在内的VL感染相关影响因素。
方法 本研究采用横断面研究设计，研究对象选自巴西联邦特区内的犬内脏利什曼病（canine visceral leishmaniasis, CVL）流行区域。通过寄生虫学、血清学及分子生物学方法检测犬只的感染情况，并采用泊松回归模型（Poisson regression modelling）分析感染相关影响因素。
结果 本次研究的VL感染流行率为26.25%[95%置信区间（confidence interval, CI）：20.05~33.57]。确认的相关影响因素包括：被毛较短（患病率比（prevalence ratio, PR）=2.33，95%CI：1.02~5.22）；拥有以土壤和/或植被为主的庭院（PR=4.15，95%CI：1.35~12.77）；家庭总收入等级最高（PR=2.03，95%CI：1.16~3.54）。
主要结论 本研究首次将犬主人较高的社会经济地位确定为与VL高感染率相关的独立风险因素，同时还验证了其他与白蛉（phlebotomines）适宜滋生环境密切相关的风险因素。本研究结果提示，未来需开展前瞻性队列研究，进一步探索犬主人特征与犬只感染风险之间关联的生物学及行为学机制。