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Gürtler RE, Enriquez GF, Gaspe MS, Macchiaverna NP, Del Pilar Fernández M, Rodríguez-Planes LI, Provecho YM, Cardinal MV. The Pampa del Indio project: sustainable vector control and long-term declines in the prevalence and abundance of Triatoma infestans infected with Trypanosoma cruzi in the Argentine Chaco. Parasit Vectors 2023; 16:258. [PMID: 37528423 PMCID: PMC10394798 DOI: 10.1186/s13071-023-05861-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 06/30/2023] [Indexed: 08/03/2023] Open
Abstract
BACKGROUND The Gran Chaco region is a major hotspot of Chagas disease. We implemented a 9-year program aimed at suppressing house infestation with Triatoma infestans and stopping vector-borne transmission to creole and indigenous (Qom) residents across Pampa del Indio municipality (Argentine Chaco). The aim of the present study was to assess the intervention effects on parasite-based transmission indices and the spatial distribution of the parasite, and test whether house-level variations in triatomine infection with Trypanosoma cruzi declined postintervention and were influenced by household ethnicity, persistent infestation linked to pyrethroid resistance and other determinants of bug infection. METHODS This longitudinal study assessed house infestation and bug infection with T. cruzi before and after spraying houses with pyrethroids and implemented systematic surveillance-and-response measures across four operational areas over the period 2007-2016. Live triatomines were individually examined for infection by optical microscopy or kinetoplast DNA (kDNA)-PCR and declared to be infected with T. cruzi when assessed positive by either method. RESULTS The prevalence of infection with T. cruzi was 19.4% among 6397 T. infestans examined. Infection ranged widely among the study areas (12.5-26.0%), household ethnicity (15.3-26.9%), bug ecotopes (1.8-27.2%) and developmental stages (5.9-27.6%), and decreased from 24.1% (baseline) to 0.9% (endpoint). Using random-intercept multiple logistic regression, the relative odds of bug infection strongly decreased as the intervention period progressed, and increased with baseline domestic infestation and bug stage and in Qom households. The abundance of infected bugs and the proportion of houses with ≥ 1 infected bug remained depressed postintervention and were more informative of area-wide risk status than the prevalence of bug infection. Global spatial analysis revealed sharp changes in the aggregation of bug infection after the attack phase. Baseline domestic infestation and baseline bug infection strongly predicted the future occurrence of bug infection, as did persistent domestic infestation in the area with multiple pyrethroid-resistant foci. Only 19% of houses had a baseline domestic infestation and 56% had ever had ≥ 1 infected bug. CONCLUSIONS Persistent bug infection postintervention was closely associated with persistent foci generated by pyrethroid resistance. Postintervention parasite-based indices closely agreed with human serosurveys at the study endpoint, suggesting transmission blockage. The program identified households and population subgroups for targeted interventions and opened new opportunities for risk prioritization and sustainable vector control and disease prevention.
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Affiliation(s)
- Ricardo Esteban Gürtler
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
- Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad de Buenos Aires, Buenos Aires, Argentina.
| | - Gustavo Fabián Enriquez
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María Sol Gaspe
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Natalia Paula Macchiaverna
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | - Lucía Inés Rodríguez-Planes
- Instituto de Ciencias Polares, Ambiente y Recursos Naturales, Universidad Nacional de Tierra del Fuego, Ushuaia, Argentina
| | - Yael Mariana Provecho
- Ministerio de Salud de la Nación, Dirección de Control de Enfermedades Transmitidas por Vectores, Buenos Aires, Argentina
| | - Marta Victoria Cardinal
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
- Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad de Buenos Aires, Buenos Aires, Argentina.
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Alejandra A, Sol GM, Fabián EG, Paula MN, Esteban GR, Victoria CM. Marginal risk of domestic vector-borne Trypanosoma cruzi transmission after improved vector control of Triatoma infestans across a rural-to-urban gradient in the Argentine Chaco. Acta Trop 2023; 243:106933. [PMID: 37119837 DOI: 10.1016/j.actatropica.2023.106933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 05/01/2023]
Abstract
The interruption of domestic vector-borne transmission of Trypanosoma cruzi in the Americas remains one of the main goals of the World Health Organization 2021-2030 road map for neglected tropical diseases. We implemented a longitudinal intervention program over 2015-2022 to suppress (peri)domestic Triatoma infestans in the municipality of Avia Terai, Chaco Province, Argentina and found that house infestation (3851 houses inspected) and triatomine abundance decreased over the first 2 years post-intervention (YPI), and remained stable thereafter associated to moderate pyrethroid resistant foci. Here we assessed selected components of transmission risk after interventions across the rural-to-urban gradient. We used multistage random sampling to select a municipality-wide sample of T. infestans. We examined 356 insects collected in 87 houses for T. cruzi infection using kDNA-PCR and identified their bloodmeal sources using an indirect ELISA. The overall prevalence of T. cruzi infection post-intervention was 1.7% (95% CI 0.7-3.6). Few houses (5.7%) (95% CI 2.5-12.8) harbored infected triatomines across the gradient. Infected triatomines were found in 5 peri-urban or rural dwellings over 1-4 years post-intervention. No infected insect was found in the urban area. The human blood index decreased from 66.2 at baseline to 42.8 at 1YPI and then increased to 92.9 at 4-5 YPI in the few infested domiciles detected. The percentage of houses with human-fed bugs displayed a similar temporal trend. Our results indicate marginal risks of domestic vector-borne transmission across the district after implementation of the intervention program. Ensuring sustainable vector surveillance coupled with human etiological diagnosis and treatment in hiperendemic areas like the Gran Chaco region, is urgently needed. 252 words.
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Affiliation(s)
- Alvedro Alejandra
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Laboratorio de Eco-Epidemiología. Intendente Güiraldes 2160, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Gaspe María Sol
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Laboratorio de Eco-Epidemiología. Intendente Güiraldes 2160, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Enriquez Gustavo Fabián
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Laboratorio de Eco-Epidemiología. Intendente Güiraldes 2160, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Macchiaverna Natalia Paula
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Laboratorio de Eco-Epidemiología. Intendente Güiraldes 2160, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Gürtler Ricardo Esteban
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Laboratorio de Eco-Epidemiología. Intendente Güiraldes 2160, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Cardinal Marta Victoria
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Laboratorio de Eco-Epidemiología. Intendente Güiraldes 2160, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina.
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Gabrielli S, Macchioni F, Spinicci M, Strohmeyer M, Roselli M, Nicoletti A, Cicero CE, Poma V, Rojo D, Lara Y, Gómez EBC, Rojas P, Gamboa H, Villagran AL, Cosmi F, Monasterio J, Cancrini G, Bartoloni A. Long-Standing International Cooperation in Parasitology Research: A Summary of 35 Years of Activities in the Bolivian Chaco. Trop Med Infect Dis 2022; 7:tropicalmed7100275. [PMID: 36288016 PMCID: PMC9611245 DOI: 10.3390/tropicalmed7100275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/21/2022] [Accepted: 09/24/2022] [Indexed: 11/16/2022] Open
Abstract
The Bolivian Chaco is a semiarid region with a low population density, situated in the southeast part of the Plurinational State of Bolivia. Here, despite the improvements of the last 15 years, poverty remains high in rural areas, where social vulnerability is widespread. The Guaraní ethnic group often lives in isolated communities with a low standard of hygiene and sanitation. This epidemiological scenario favors the spread of transmissible diseases, including several parasitic infections belonging to the neglected tropical diseases (NTDs) group. In this area, a long-standing research activity, built upon the synergism between local and foreign institutions, has been established since the late 1980s and helps to fill in the knowledge gap about the epidemiology dynamics of soil-transmitted helminths, vector-borne parasites, and other parasitic diseases. A 35-year history of cooperation programs in parasitology research has contributed to informing local health authorities of the NTD burden in the Bolivian Chaco and, ultimately, supports local healthcare providers in the management of parasitic diseases.
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Affiliation(s)
- Simona Gabrielli
- Dipartimento di Sanità Pubblica e Malattie Infettive, Sapienza Università di Roma, 00185 Rome, Italy
| | - Fabio Macchioni
- Dipartimento di Scienze Veterinarie, Università di Pisa, 56124 Pisa, Italy
| | - Michele Spinicci
- Dipartimento Medicina Sperimentale e Clinica, Università degli Studi di Firenze, 50121 Florence, Italy
| | - Marianne Strohmeyer
- Dipartimento Medicina Sperimentale e Clinica, Università degli Studi di Firenze, 50121 Florence, Italy
| | - Mimmo Roselli
- Dipartimento Medicina Sperimentale e Clinica, Università degli Studi di Firenze, 50121 Florence, Italy
| | - Alessandra Nicoletti
- Dipartimento di Scienze Mediche, Chirurgiche e Tecnologie Avanzate G.F. Ingrassia, Sez. di Neuroscienze, Università di Catania, 95125 Catania, Italy
| | - Calogero Edoardo Cicero
- Dipartimento di Scienze Mediche, Chirurgiche e Tecnologie Avanzate G.F. Ingrassia, Sez. di Neuroscienze, Università di Catania, 95125 Catania, Italy
| | - Veronica Poma
- Escuela de Salud del Chaco Tekove Katu, Gutierrez, Bolivia
| | - David Rojo
- Escuela de Salud del Chaco Tekove Katu, Gutierrez, Bolivia
| | - Yunni Lara
- Hospital San Antonio de los Sauces, Monteagudo, Bolivia
| | | | | | - Herlan Gamboa
- Facultad Integral del Chaco, Universidad Autónoma Gabriel René Moreno, Camiri, Bolivia
| | | | | | - Joaquín Monasterio
- Servicio Departamental de Salud (SEDES) de Santa Cruz, Santa Cruz, Bolivia
| | - Gabriella Cancrini
- Dipartimento di Sanità Pubblica e Malattie Infettive, Sapienza Università di Roma, 00185 Rome, Italy
| | - Alessandro Bartoloni
- Dipartimento Medicina Sperimentale e Clinica, Università degli Studi di Firenze, 50121 Florence, Italy
- Correspondence:
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