Improved vector control of Triatoma infestans limited by emerging pyrethroid resistance across an urban-to-rural gradient in the Argentine Chaco

Parasites & Vectors

Pablo Luis Santo-Orihuela¹  Claudia Viviana Vassena²  Julián Antonio Alvarado-Otegui³  Alejandra Alvedro⁴  Ricardo Esteban Gürtler⁴  Gustavo Fabián Enriquez⁴  María Carla Cecere⁴  Natalia Paula Macchiaverna⁴  Mariano Alberto Laiño⁴  Julieta Nattero⁴  Marta Victoria Cardinal⁴  María Sol Gaspe⁴  María del Pilar Fernández⁵  Héctor Freilij⁶ 

[1] Centro de Investigaciones de Plagas e Insecticidas (CIPEIN, CONICET/UNIDEF/CITEDEF), Juan Bautista La Salle 4397, Villa Martelli, CP 1603, Buenos Aires, Argentina;Cátedra de Química Analítica Instrumental, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina;Centro de Investigaciones de Plagas e Insecticidas (CIPEIN, CONICET/UNIDEF/CITEDEF), Juan Bautista La Salle 4397, Villa Martelli, CP 1603, Buenos Aires, Argentina;Universidad Nacional de San Martín, Buenos Aires, Argentina;Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina;Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina;Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina;Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina;Washington State University, Paul G. Allen School for Global Animal Health, Allen Center, 1155 College Ave., 99164, Pullman, WA, USA;Servicio de Parasitología, Hospital de Niños Ricardo Gutiérrez, Instituto Multidisciplinario de Investigación en Patologías Pediátricas, CONICET-GCBA, Buenos Aires, Argentina;

关键词: Gran Chaco;    Sustainability;    Triatoma infestans;    Urban;    Vector control;    Pyrethroid resistance;   

DOI  :  10.1186/s13071-021-04942-9

来源: Springer

【 摘 要 】

BackgroundThe sustainable elimination of Triatoma infestans in the Gran Chaco region represents an enduring challenge. Following the limited effects of a routine pyrethroid insecticide spraying campaign conducted over 2011–2013 (first period) in Avia Terai, an endemic municipality with approximately 2300 houses, we implemented a rapid-impact intervention package to suppress house infestation across the urban-to-rural gradient over 2015–2019 (second period). Here, we assess their impacts and whether persisting infestations were associated with pyrethroid resistance.MethodsThe 2011–2013 campaign achieved a limited detection and spray coverage across settings (< 68%), more so during the surveillance phase. Following community mobilization and school-based interventions, the 2015–2019 program assessed baseline house infestation using a stratified sampling strategy; sprayed all rural houses with suspension concentrate beta-cypermethrin, and selectively sprayed infested and adjacent houses in urban and peri-urban settings; and monitored house infestation and performed selective treatments over the follow-up.ResultsOver the first period, house infestation returned to pre-intervention levels within 3–4 years. The adjusted relative odds of house infestation between 2011–2013 and 2015–2016 differed very little (adj. OR: 1.17, 95% CI 0.91–1.51). Over the second period, infestation decreased significantly between 0 and 1 year post-spraying (YPS) (adj. OR: 0.36, 95% CI 0.28–0.46), with heterogeneous effects across the gradient. Mean bug abundance also dropped between 0 and 1 YPS and thereafter remained stable in rural and peri-urban areas. Using multiple regression models, house infestation and bug abundance at 1 YPS were 3–4 times higher if the house had been infested before treatment, or was scored as high-risk or non-participating. No low-risk house was ever infested. Persistent foci over two successive surveys increased from 30.0 to 59.3% across the gradient. Infestation was more concentrated in peridomestic rather than domestic habitats. Discriminating-dose bioassays showed incipient or moderate pyrethroid resistance in 7% of 28 triatomine populations collected over 2015–2016 and in 83% of 52 post-spraying populations.ConclusionsThe intervention package was substantially more effective than the routine insecticide spraying campaign, though the effects were lower than predicted due to unexpected incipient or moderate pyrethroid resistance. Increased awareness and diagnosis of vector control failures in the Gran Chaco, including appropriate remedial actions, are greatly needed.Graphical abstract

【 授权许可】

CC BY