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Long-term impact of a ten-year intervention program on human and canine Trypanosoma cruzi infection in the Argentine Chaco

BACKGROUND: Interruption of domestic vector-borne transmission of Trypanosoma cruzi is still an unmet goal in several American countries. In 2007 we launched a long-term intervention program aimed to suppress house infestation with the main domestic vector in southern South America (Triatoma infesta...

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Autores principales: Cardinal, Marta Victoria, Enriquez, Gustavo Fabián, Macchiaverna, Natalia Paula, Argibay, Hernán Darío, Fernández, María del Pilar, Alvedro, Alejandra, Gaspe, María Sol, Gürtler, Ricardo Esteban
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8115854/
https://www.ncbi.nlm.nih.gov/pubmed/33979344
http://dx.doi.org/10.1371/journal.pntd.0009389
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author Cardinal, Marta Victoria
Enriquez, Gustavo Fabián
Macchiaverna, Natalia Paula
Argibay, Hernán Darío
Fernández, María del Pilar
Alvedro, Alejandra
Gaspe, María Sol
Gürtler, Ricardo Esteban
author_facet Cardinal, Marta Victoria
Enriquez, Gustavo Fabián
Macchiaverna, Natalia Paula
Argibay, Hernán Darío
Fernández, María del Pilar
Alvedro, Alejandra
Gaspe, María Sol
Gürtler, Ricardo Esteban
author_sort Cardinal, Marta Victoria
collection PubMed
description BACKGROUND: Interruption of domestic vector-borne transmission of Trypanosoma cruzi is still an unmet goal in several American countries. In 2007 we launched a long-term intervention program aimed to suppress house infestation with the main domestic vector in southern South America (Triatoma infestans) and domestic transmission in Pampa del Indio, a resource-constrained, hyperendemic municipality with 1446 rural houses inhabited by Creole and indigenous people, in the Argentine Chaco ecoregion. Here, we assessed whether the 10-year insecticide-based program combined with community mobilization blocked vector-borne domestic transmission of T. cruzi to humans and dogs. METHODS: We carried out two municipality-wide, cross-sectional serosurveys of humans and dogs (considered sentinel animals) during 2016–2017 to compare with baseline data. We used a risk-stratified random sampling design to select 273 study houses; 410 people from 180 households and 492 dogs from 151 houses were examined for antibodies to T. cruzi using at least two serological methods. RESULTS: The seroprevalence of T. cruzi in children aged <16 years was 2.5% in 2017 (i.e., 4- to 11-fold lower than before interventions). The mean annual force of child infection (λ) sharply decreased from 2.18 to 0.34 per 100 person-years in 2017. One of 102 children born after interventions was seropositive for T. cruzi; he had lifetime residence in an apparently uninfested house, no outside travel history, and his mother was T. cruzi-seropositive. No incident case was detected among 114 seronegative people of all ages re-examined serologically. Dog seroprevalence was 3.05%. Among native dogs, λ in 2016 (1.21 per 100 dog-years) was 5 times lower than at program onset. Six native adult dogs born after interventions and with stable lifetime residence were T. cruzi-seropositive: three had exposure to T. infestans at their houses and one was an incident case. CONCLUSIONS: These results support the interruption of vector-borne transmission of T. cruzi to humans in rural Pampa del Indio. Congenital transmission was the most likely source of the only seropositive child born after interventions. Residual transmission to dogs was likely related to transient infestations and other transmission routes. Sustained vector control supplemented with human chemotherapy can lead to a substantial reduction of Chagas disease transmission in the Argentine Chaco.
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spelling pubmed-81158542021-05-24 Long-term impact of a ten-year intervention program on human and canine Trypanosoma cruzi infection in the Argentine Chaco Cardinal, Marta Victoria Enriquez, Gustavo Fabián Macchiaverna, Natalia Paula Argibay, Hernán Darío Fernández, María del Pilar Alvedro, Alejandra Gaspe, María Sol Gürtler, Ricardo Esteban PLoS Negl Trop Dis Research Article BACKGROUND: Interruption of domestic vector-borne transmission of Trypanosoma cruzi is still an unmet goal in several American countries. In 2007 we launched a long-term intervention program aimed to suppress house infestation with the main domestic vector in southern South America (Triatoma infestans) and domestic transmission in Pampa del Indio, a resource-constrained, hyperendemic municipality with 1446 rural houses inhabited by Creole and indigenous people, in the Argentine Chaco ecoregion. Here, we assessed whether the 10-year insecticide-based program combined with community mobilization blocked vector-borne domestic transmission of T. cruzi to humans and dogs. METHODS: We carried out two municipality-wide, cross-sectional serosurveys of humans and dogs (considered sentinel animals) during 2016–2017 to compare with baseline data. We used a risk-stratified random sampling design to select 273 study houses; 410 people from 180 households and 492 dogs from 151 houses were examined for antibodies to T. cruzi using at least two serological methods. RESULTS: The seroprevalence of T. cruzi in children aged <16 years was 2.5% in 2017 (i.e., 4- to 11-fold lower than before interventions). The mean annual force of child infection (λ) sharply decreased from 2.18 to 0.34 per 100 person-years in 2017. One of 102 children born after interventions was seropositive for T. cruzi; he had lifetime residence in an apparently uninfested house, no outside travel history, and his mother was T. cruzi-seropositive. No incident case was detected among 114 seronegative people of all ages re-examined serologically. Dog seroprevalence was 3.05%. Among native dogs, λ in 2016 (1.21 per 100 dog-years) was 5 times lower than at program onset. Six native adult dogs born after interventions and with stable lifetime residence were T. cruzi-seropositive: three had exposure to T. infestans at their houses and one was an incident case. CONCLUSIONS: These results support the interruption of vector-borne transmission of T. cruzi to humans in rural Pampa del Indio. Congenital transmission was the most likely source of the only seropositive child born after interventions. Residual transmission to dogs was likely related to transient infestations and other transmission routes. Sustained vector control supplemented with human chemotherapy can lead to a substantial reduction of Chagas disease transmission in the Argentine Chaco. Public Library of Science 2021-05-12 /pmc/articles/PMC8115854/ /pubmed/33979344 http://dx.doi.org/10.1371/journal.pntd.0009389 Text en © 2021 Cardinal et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Cardinal, Marta Victoria
Enriquez, Gustavo Fabián
Macchiaverna, Natalia Paula
Argibay, Hernán Darío
Fernández, María del Pilar
Alvedro, Alejandra
Gaspe, María Sol
Gürtler, Ricardo Esteban
Long-term impact of a ten-year intervention program on human and canine Trypanosoma cruzi infection in the Argentine Chaco
title Long-term impact of a ten-year intervention program on human and canine Trypanosoma cruzi infection in the Argentine Chaco
title_full Long-term impact of a ten-year intervention program on human and canine Trypanosoma cruzi infection in the Argentine Chaco
title_fullStr Long-term impact of a ten-year intervention program on human and canine Trypanosoma cruzi infection in the Argentine Chaco
title_full_unstemmed Long-term impact of a ten-year intervention program on human and canine Trypanosoma cruzi infection in the Argentine Chaco
title_short Long-term impact of a ten-year intervention program on human and canine Trypanosoma cruzi infection in the Argentine Chaco
title_sort long-term impact of a ten-year intervention program on human and canine trypanosoma cruzi infection in the argentine chaco
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8115854/
https://www.ncbi.nlm.nih.gov/pubmed/33979344
http://dx.doi.org/10.1371/journal.pntd.0009389
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