背景:拟除虫菊酯抗性的出现已经威胁到从GranChaco生态区消除Triatoma侵染物。我们调查了Castelli中T.infestans的房屋侵扰状况和空间分布及其主要决定因素,阿根廷查科的一个自治市,对拟除虫菊酯的抗药性达到创纪录水平,2005-2014年持续感染,2015-2020年有限或没有控制行动。
方法:我们在2018年(基线)和2020年在Castelli明确定义的农村地区(包括14个村庄和234个有人居住的房屋)进行了为期2年的纵向调查,以通过现场检查和量身定制的问卷收集住房和社会人口统计数据。并将这些数据合成为通过多重对应分析生成的三个指标。
结果:2018年(33.8%)和2020年(31.6%)的房屋侵扰的总体患病率与复发性拟除虫菊酯喷雾剂的2005-2014年(33.7%)的历史估计相符。虽然在2018年至2020年期间,平均腹地侵扰保持不变(26.4-26.7%),但国内侵扰从12.2%略微下降至8.3%。主要的三草碱栖息地是储藏室,domiciles,厨房,和被鸡占据的结构。局部空间分析表明,五个村庄的侵染和虫子丰度显著聚集,其中四个在大约2010-2013年期间具有非常高的拟除虫菊酯抗性,表明在时空上持续感染。热点地区的房屋虫子数量一直超过其他村庄记录的估计值。多元回归分析显示,住所中T.infestans的存在和相对丰度与家庭预防实践(农药使用)和住房质量指数呈强烈负相关。问卷调查得出的信息显示,与牲畜饲养有关的拟除虫菊酯的广泛使用以及对狗和(周围)家庭场所的溢出治疗。
结论:尽管在5年内采取了有限或有限的控制措施,但在具有高拟除虫菊酯抗性的地区,Triatoma感染人群的恢复和繁殖速度缓慢。与这些模式一致,独立的实验证实,与易感的同种异体相比,Castelli中拟除虫菊酯抗性的triatomines的适应度较低。需要通过适当的房屋改造措施来针对热点和对拟除虫菊酯抗性的焦点,并明智地使用具有足够毒性的替代杀虫剂,以抑制对曲藻碱的抗性种群并防止其最终的区域传播。
BACKGROUND: The emergence of pyrethroid resistance has threatened the elimination of Triatoma infestans from the Gran Chaco ecoregion. We investigated the status and spatial distribution of house infestation with T. infestans and its main determinants in Castelli, a municipality of the Argentine Chaco with record levels of triatomine pyrethroid resistance, persistent infestation over 2005-2014, and limited or no control actions over 2015-2020.
METHODS: We conducted a 2-year longitudinal survey to assess triatomine infestation by timed manual searches in a well-defined rural section of Castelli including 14 villages and 234 inhabited houses in 2018 (baseline) and 2020, collected housing and sociodemographic data by on-site inspection and a tailored questionnaire, and synthetized these data into three indices generated by multiple correspondence analysis.
RESULTS: The overall prevalence of house infestation in 2018 (33.8%) and 2020 (31.6%) virtually matched the historical estimates for the period 2005-2014 (33.7%) under recurrent pyrethroid sprays. While mean peridomestic infestation remained the same (26.4-26.7%) between 2018 and 2020, domestic infestation slightly decreased from 12.2 to 8.3%. Key triatomine habitats were storerooms, domiciles, kitchens, and structures occupied by chickens. Local spatial analysis showed significant aggregation of infestation and bug abundance in five villages, four of which had very high pyrethroid resistance approximately over 2010-2013, suggesting persistent infestations over space-time. House bug abundance within the hotspots consistently exceeded the estimates recorded in other villages. Multiple regression analysis revealed that the presence and relative abundance of T. infestans in domiciles were strongly and negatively associated with indices for household preventive practices (pesticide use) and housing quality. Questionnaire-derived information showed extensive use of pyrethroids associated with livestock raising and concomitant spillover treatment of dogs and (peri) domestic premises.
CONCLUSIONS: Triatoma infestans populations in an area with high pyrethroid resistance showed slow recovery and propagation rates despite limited or marginal control actions over a 5-year period. Consistent with these patterns, independent experiments confirmed the lower fitness of pyrethroid-resistant triatomines in Castelli compared with susceptible conspecifics. Targeting hotspots and pyrethroid-resistant foci with appropriate house modification measures and judicious application of alternative insecticides with adequate toxicity profiles are needed to suppress resistant triatomine populations and prevent their eventual regional spread.