Data_Sheet_1_Molecular survey of Zika virus in the animal-human interface in traditional farming.docx

Backyard animal husbandry is common in rural communities in developing countries and, given the conditions in which it occurs, it can increase the risk of disease transmission, such as arboviruses. To determine the presence of the Zika virus (ZIKV) and abundance of its arthropod vectors we evaluated the socioeconomic implications involved in its transmission in two highly vulnerable Mayan communities in the state of Yucatan that practice backyard farming. An analytical cross-sectional study was carried out throughout 2016 to understand socioeconomic variables and seasonal patterns in mosquito populations. We selected 20 households from each community. Social exclusion indicators were analyzed, human and domestic animals were sampled, and mosquitoes were collected and identified. Four out of eight indicators of social exclusion were higher than the reported national averages. We captured 5,825 mosquitoes from 16 species being Culex quinquefasciatus and Aedes aegypti the most abundant. The presence of chickens and human overcrowding in dwellings were the most significant factors (P = 0.026) associated with the presence of Ae. aegypti. Septic tanks (odds ratio = 6.64) and chickens (odds ratio = 27.41) in backyards were the main risk factors associated with the presence of immature states of Ae. aegypti in both communities. Molecular analysis to detect ZIKV was performed in blood samples from 416 humans, 1,068 backyard animals and 381 mosquito pools. Eighteen humans and 10 pig pools tested positive for ZIKV. Forty-three mosquito pools tested positive for flavivirus. Ten of the 43 pools of positive mosquitoes were sequenced, corresponding 3/10 to ZIKV and 1/10 to Dengue virus type 2. The findings obtained indicate the continuous circulation of Flavivirus (including ZIKV) in backyard environments in vulnerable communities, highlighting the importance of studying their transmission and maintenance in these systems, due that backyard animal husbandry is a common practice in these vulnerable communities with limited access to health services.

后院畜牧（backyard animal husbandry）在发展中国家农村社区中极为普遍，而其开展的相关环境条件可能会提升虫媒病毒等疾病的传播风险。为明确寨卡病毒（Zika virus, ZIKV）的存在情况及其节肢动物媒介的丰度，本研究针对尤卡坦州两个从事后院养殖的高脆弱性玛雅社区，评估了其病毒传播相关的社会经济影响。研究于2016年全年开展分析性横断面研究，以明确蚊虫种群的社会经济变量与季节模式。每个社区选取20户家庭，对社会排斥指标进行分析，采集人类与家养动物样本，并收集、鉴定蚊虫。八项社会排斥指标中有四项高于该国全国平均水平。本次研究共捕获5825只蚊虫，隶属于16个物种，其中致倦库蚊（Culex quinquefasciatus）与埃及伊蚊（Aedes aegypti）为优势种群。住宅内养鸡行为及住宅人口过度拥挤，是与埃及伊蚊存在相关的最显著影响因素（P=0.026）。后院化粪池（比值比=6.64）与养鸡行为（比值比=27.41），是两个社区中与埃及伊蚊幼虫阶段存在相关的主要危险因素。本研究对416份人类血液样本、1068份后院养殖动物血液样本及381份蚊虫混池样本开展寨卡病毒检测的分子分析。结果显示，18份人类样本与10份猪混池样本寨卡病毒检测呈阳性；43份蚊虫混池样本黄病毒（flavivirus）检测呈阳性。对43份阳性蚊虫混池样本中的10份进行测序，其中3/10对应寨卡病毒，1/10对应登革病毒2型（Dengue virus type 2）。本研究结果表明，黄病毒科病毒（包括寨卡病毒）在脆弱社区的后院环境中持续循环。鉴于后院畜牧在医疗服务可及性有限的这类脆弱社区中属于普遍实践，凸显了研究此类系统中病毒传播与维持机制的重要性。