Abstract：
Insecticide resistance is considered a barrier to chemical control of Triatoma infestans, the main vector of Chagas disease in the Southern Cone of South America. Although initiatives to reduce the incidence of the disease in the region have integrated different strategies, they have mainly relied on vector elimination using pyrethroid insecticides such as deltamethrin. Reports of pyrethroid resistance in connection with T. infestans control failures first emerged in northern Argentina and southern Bolivia. Recently, a mosaic pyrethroid-resistant focus has been described in the center of the Argentine Gran Chaco (Department of General Güemes, Chaco Province), characterized by the presence of susceptible and very highly resistant populations in the same area. The involvement of different resistance mechanisms has been proposed, together with the contribution of environmental variables that promote the toxicological heterogeneity described. In the endemic zone of Argentina, however, new questions arise: Are there any other clusters of resistance? Is there a relationship between the distribution of resistance and environmental variables (as has been observed at smaller scale)? We studied toxicological data from insects collected and analyzed at 224 localities between 2010 and 2020 as part of the resistance monitoring conducted by the Chagas National Program. The sites were classified according to the survival rate of insects exposed to a discriminant dose of deltamethrin: 0-0.19 were considered susceptible, 0.2-0.79 low-resistance, and 0.8-1 high-resistance. Localities were georeferenced to describe the spatial distribution of resistance and to identify environmental variables (demographics, land use, urbanization, connectivity, and climate) potentially associated with resistance. We used Generalized Linear Models (GLMs) to examine the association between resistance and environmental predictors, selecting error distributions based on the response variable definition. For the entire period, 197 susceptible localities were distributed across the endemic zone. Localities with different survival rates were found throughout the area; 9 high-resistance localities circled the two previously identified resistant foci, and 18 low-resistance in 6 provinces, highlighting their relevance for control planning. Precipitation variables were linked to resistance in all the GLMs evaluated. Presence/absence models were the most accurate, with precipitation, distance from the capital city, and land use contributing to the distribution of resistance. This information could be valuable for improving T. infestans control strategies in future scenarios characterized by unpredictable changes in land use and precipitation.
摘要：
杀虫剂抗性被认为是对Triatoma感染的化学控制的障碍，南美南锥体锥虫病的主要病媒。尽管减少该地区疾病发病率的举措整合了不同的战略，他们主要依靠使用拟除虫菊酯杀虫剂如溴氰菊酯的媒介消除。在阿根廷北部和玻利维亚南部，首次出现了与T.infestans控制失败有关的拟除虫菊酯抗性的报道。最近,在阿根廷GranChaco（Güemes将军部，ChacoProvince),其特征是在同一地区存在易感和非常高抗性的种群。已经提出了不同抗性机制的参与，以及促进所描述的毒理学异质性的环境变量的贡献。在阿根廷的流行区，然而,新的问题出现了：是否还有其他的抗性集群？抗性的分布与环境变量之间是否存在关系（如在较小规模观察到的）？我们研究了2010年至2020年期间在224个地区收集和分析的昆虫的毒理学数据，作为查加斯国家计划进行的抗性监测的一部分。根据暴露于有区别剂量的溴氰菊酯的昆虫的存活率对这些地点进行分类：0-0.19被认为是易感的，0.2-0.79低电阻，和0.8-1高电阻。对位置进行了地理参考，以描述阻力的空间分布并识别环境变量(人口统计，土地利用,城市化,连通性,和气候）可能与抵抗力有关。我们使用广义线性模型(GLM)来检验抗性与环境预测因子之间的关联，根据响应变量定义选择误差分布。在整个时期,197个易感地区分布在流行区。在整个地区发现了存活率不同的地区；9个高抗性地区围绕着两个先前确定的抗性病灶，和6个省的18个低阻力，强调它们与控制规划的相关性。在所有评估的GLM中，降水变量与电阻相关。在场/缺席模型是最准确的，随着降水,离首都很远,和土地利用有助于阻力的分布。这些信息对于在以土地利用和降水不可预测的变化为特征的未来情景中改善T.infestans控制策略可能是有价值的。
