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Elias DE, Cardinal MV, Macchiaverna NP, Enriquez GF, Gürtler RE, Gaspe MS. Domestic (re)infestation risk with the main vector Triatoma infestans increases with surrounding green vegetation and social vulnerability in the Argentine Chaco. Parasit Vectors 2024; 17:240. [PMID: 38802953 PMCID: PMC11131304 DOI: 10.1186/s13071-024-06324-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 05/13/2024] [Indexed: 05/29/2024] Open
Abstract
BACKGROUND Chagas disease, caused by Trypanosoma cruzi, is still a public health problem in Latin America and in the Southern Cone countries, where Triatoma infestans is the main vector. We evaluated the relationships among the density of green vegetation around rural houses, sociodemographic characteristics, and domestic (re)infestation with T. infestans while accounting for their spatial dependence in the municipality of Pampa del Indio between 2007 and 2016. METHODS The study comprised sociodemographic and ecological variables from 734 rural houses with no missing data. Green vegetation density surrounding houses was estimated by the normalized difference vegetation index (NDVI). We used a hierarchical Bayesian logistic regression composed of fixed effects and spatial random effects to estimate domestic infestation risk and quantile regressions to evaluate the association between surrounding NDVI and selected sociodemographic variables. RESULTS Qom ethnicity and the number of poultry were negatively associated with surrounding NDVI, whereas overcrowding was positively associated with surrounding NDVI. Hierarchical Bayesian models identified that domestic infestation was positively associated with surrounding NDVI, suitable walls for triatomines, and overcrowding over both intervention periods. Preintervention domestic infestation also was positively associated with Qom ethnicity. Models with spatial random effects performed better than models without spatial effects. The former identified geographic areas with a domestic infestation risk not accounted for by fixed-effect variables. CONCLUSIONS Domestic infestation with T. infestans was associated with the density of green vegetation surrounding rural houses and social vulnerability over a decade of sustained vector control interventions. High density of green vegetation surrounding rural houses was associated with households with more vulnerable social conditions. Evaluation of domestic infestation risk should simultaneously consider social, landscape and spatial effects to control for their mutual dependency. Hierarchical Bayesian models provided a proficient methodology to identify areas for targeted triatomine and disease surveillance and control.
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Affiliation(s)
- Dario E Elias
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de 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, Ciudad Autónoma de Buenos Aires, Argentina.
| | - Marta V Cardinal
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de 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, Ciudad Autónoma de Buenos Aires, Argentina
| | - Natalia P Macchiaverna
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de 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, Ciudad Autónoma de Buenos Aires, Argentina
| | - Gustavo F Enriquez
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de 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, Ciudad Autónoma de Buenos Aires, Argentina
| | - Ricardo E Gürtler
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de 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, Ciudad Autónoma de Buenos Aires, Argentina
| | - M Sol Gaspe
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de 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, Ciudad Autónoma de Buenos Aires, Argentina.
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Gürtler RE, Gaspe MS, Macchiaverna NP, Enriquez GF, Rodríguez-Planes LI, Fernández MDP, Provecho YM, Cardinal MV. The Pampa del Indio project: District-wide quasi-elimination of Triatoma infestans after a 9-year intervention program in the Argentine Chaco. PLoS Negl Trop Dis 2023; 17:e0011252. [PMID: 37093886 PMCID: PMC10159358 DOI: 10.1371/journal.pntd.0011252] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 05/04/2023] [Accepted: 03/19/2023] [Indexed: 04/25/2023] Open
Abstract
BACKGROUND The elimination of Triatoma infestans, the main domestic vector of Trypanosoma cruzi, is lagging behind expectations in the Gran Chaco region. We implemented an insecticide-based intervention program and assessed its long-term effects on house infestation and bug abundance in a resource-constrained municipality (Pampa del Indio, northeastern Argentina) inhabited by creole and the Qom indigenous people (2007-2016). Key questions were whether district-wide data integration revealed patterns concealed at lower spatial levels; to what extent preintervention infestation and pyrethroid resistance challenged the effectiveness of insecticide-based control efforts, and how much control effort was needed to meet defined targets. METHODS Supervised vector control teams i) georeferenced every housing unit at baseline (1,546); ii) evaluated house infestation using timed-manual searches with a dislodging aerosol across four rural areas designated for district-wide scaling up; iii) sprayed with pyrethroid insecticide 92.7% of all houses; iv) periodically monitored infestation and promoted householder-based surveillance, and v) selectively sprayed the infested houses, totaling 1,823 insecticide treatments throughout the program. RESULTS Baseline house infestation (mean, 26.8%; range, 14.4-41.4%) and bug abundance plummeted over the first year postintervention (YPI). Timed searches at baseline detected 61.4-88.0% of apparent infestations revealed by any of the methods used. Housing dynamics varied widely among areas and between Qom and creole households. Preintervention triatomine abundance and the cumulative frequency of insecticide treatments were spatially aggregated in three large clusters overlapping with pyrethroid resistance, which ranged from susceptible to high. Persistent foci were suppressed with malathion. Aggregation occurred mainly at house compound or village levels. Preintervention domestic infestation and abundance were much greater in Qom than in creole households, whereas the reverse was recorded in peridomestic habitats. House infestation, rare (1.9-3.7%) over 2-6 YPI, averaged 0.66% (95% confidence interval, 0.28-1.29%) at endpoint. CONCLUSIONS Upscale integration revealed multiple coupled heterogeneities (spatial, sociodemographic and biological) that reflect large inequalities, hamper control efforts, and provide opportunities for targeted, sustainable disease control. High-coverage, professional insecticide spraying combined with systematic surveillance-and-response were essential ingredients to achieve the quasi-elimination of T. infestans within 5 YPI and concomitant transmission blockage despite various structural threats and constraints.
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Affiliation(s)
- Ricardo Esteban Gürtler
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Laboratorio de Eco-Epidemiología, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - María Sol Gaspe
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Laboratorio de Eco-Epidemiología, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - Natalia Paula Macchiaverna
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Laboratorio de Eco-Epidemiología, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - Gustavo Fabián Enriquez
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Laboratorio de Eco-Epidemiología, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - Lucía Inés Rodríguez-Planes
- Instituto de Ciencias Polares, Ambiente y Recursos Naturales, Universidad Nacional de Tierra del Fuego, Ushuaia, Argentina
| | - María Del Pilar Fernández
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
| | - Yael Mariana Provecho
- Ministerio de Salud de la Nación, Dirección de Control de Enfermedades Transmitidas por Vectores, Buenos Aires, Argentina
| | - Marta Victoria Cardinal
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Laboratorio de Eco-Epidemiología, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
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Christopher DM, Curtis-Robles R, Hamer GL, Bejcek J, Saunders AB, Roachell WD, Cropper TL, Hamer SA. Collection of triatomines from sylvatic habitats by a Trypanosoma cruzi-infected scent detection dog in Texas, USA. PLoS Negl Trop Dis 2023; 17:e0010813. [PMID: 36940217 PMCID: PMC10063167 DOI: 10.1371/journal.pntd.0010813] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 03/30/2023] [Accepted: 02/14/2023] [Indexed: 03/21/2023] Open
Abstract
BACKGROUND Triatomine insects, vectors of the etiologic agent of Chagas disease (Trypanosoma cruzi), are challenging to locate in sylvatic habitats. Collection techniques used in the United States often rely on methods to intercept seasonally dispersing adults or on community scientists' encounters. Neither method is suited for detecting nest habitats likely to harbor triatomines, which is important for vector surveillance and control. Furthermore, manual inspection of suspected harborages is difficult and unlikely to reveal novel locations and host associations. Similar to a team that used a trained dog to detect sylvatic triatomines in Paraguay, we worked with a trained scent detection dog to detect triatomines in sylvatic locations across Texas. PRINCIPLE METHODOLOGY/FINDINGS Ziza, a 3-year-old German Shorthaired Pointer previously naturally infected with T. cruzi, was trained to detect triatomines. Over the course of 6 weeks in the fall of 2017, the dog and her handler searched at 17 sites across Texas. The dog detected 60 triatomines at 6 sites; an additional 50 triatomines were contemporaneously collected at 1 of these sites and 2 additional sites without the assistance of the dog. Approximately 0.98 triatomines per hour were found when only humans were conducting searches; when working with the dog, approximately 1.71 triatomines per hour were found. In total, 3 adults and 107 nymphs of four species (Triatoma gerstaeckeri, Triatoma protracta, Triatoma sanguisuga, and Triatoma indictiva) were collected. PCR testing of a subset revealed T. cruzi infection, including DTUs TcI and TcIV, in 27% of nymphs (n = 103) and 66% of adults (n = 3). Bloodmeal analysis of a subset of triatomines (n = 5) revealed feeding on Virginia opossum (Didelphis virginiana), Southern plains woodrat (Neotoma micropus), and eastern cottontail (Sylvilagus floridanus). CONCLUSION/SIGNIFICANCE A trained scent detection dog enhanced triatomine detections in sylvatic habitats. This approach is effective at detecting nidicolous triatomines. Control of sylvatic sources of triatomines is challenging, but this new knowledge of specific sylvatic habitats and key hosts may reveal opportunities for novel vector control methods to block the transmission of T. cruzi to humans and domestic animals.
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Affiliation(s)
| | - Rachel Curtis-Robles
- Department of Veterinary Integrative Biosciences, School of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
| | - Gabriel L. Hamer
- Department of Entomology, Texas A&M University, College Station, Texas, United States of America
| | - Justin Bejcek
- Department of Veterinary Integrative Biosciences, School of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
- Department of Entomology, Texas A&M University, College Station, Texas, United States of America
| | - Ashley B. Saunders
- Department of Small Animal Clinical Sciences, School of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
| | - Walter D. Roachell
- Public Health Command Central, JBSA-Fort Sam Houston, San Antonio, Texas, United States of America
| | - Thomas Leo Cropper
- Wilford Hall Ambulatory Surgical Center, Joint Base San Antonio, San Antonio Texas
| | - Sarah A. Hamer
- Department of Veterinary Integrative Biosciences, School of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
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Gómez-Sánchez EF, Ochoa-Díaz-López H, Espinoza-Medinilla EE, Velázquez-Ramírez DD, Santos-Hernandez NG, Ruiz-Castillejos C, Vidal-López DG, Moreno-Rodríguez A, Flores-Villegas AL, López-Argueta E, De Fuentes-Vicente JA. Mini-exon gene reveals circulation of TcI Trypanosoma cruzi (Chagas, 1909) (Kinetoplastida, Trypanosomatidae) in bats and small mammals in an ecological reserve in southeastern Mexico. Zookeys 2022; 1084:139-150. [PMID: 35177949 PMCID: PMC8816842 DOI: 10.3897/zookeys.1084.78664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/14/2022] [Indexed: 11/27/2022] Open
Abstract
A wide variety of mammals are involved in the sylvatic cycle of Trypanosomacruzi, the causative agent of Chagas disease. In many areas in Latin America where T.cruzi is endemic, this cycle is poorly known, and its main reservoirs have not been identified. In this study we analyzed T.cruzi infection in bats and other small mammals from an Ecological Reserve in southeastern Mexico. From January through March 2021, we captured wild individuals to extract cardiac and peripheral blood, and infection was detected by PCR of the mini-exon gene. In bats, the prevalence of infection was 16.36%, while in small mammals the prevalence was 28.57%. All of the samples that were positive for T.cruzi were identified as the TCI genotype. Our findings suggest that this zone, situated at the periphery of urban zones might have epidemiological relevance in the sylvatic cycle of T.cruzi and needs to be monitored. The infection of bats in this area is particularly concerning since the flight pattern of this populations overlaps with human settlements. Despite being subject to conservation protections, there continue to be anthropogenic actions that disturb the study area, which could exacerbate risks to public health.
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Cardozo M, Fiad FG, Crocco LB, Gorla DE. Effect of habitat fragmentation on rural house invasion by sylvatic triatomines: A multiple landscape-scale approach. PLoS Negl Trop Dis 2021; 15:e0009579. [PMID: 34260588 PMCID: PMC8312942 DOI: 10.1371/journal.pntd.0009579] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 07/26/2021] [Accepted: 06/21/2021] [Indexed: 11/20/2022] Open
Abstract
After the decrease of the relative importance of Triatoma infestans, a number of studies reported the occurrence of sylvatic triatomines dispersing actively to domestic environments in the dry western Chaco Region of Argentina. Anthropic modification of the landscape is mentioned as one of the main causes of the increase in domicile invasion. The aim of this study was to describe the occurrence and frequency of sylvatic triatomines invading rural houses, and to evaluate the effect of habitat fragmentation and other ecological factors on the invasion of rural houses in central Argentina. We hypothesized that the decrease in food sources and the loss of wild ecotopes, as a consequence of habitat fragmentation, increase the chances of invasion by triatomines. The entomological data was collected by community-based vector surveillance during fieldwork carried out between 2017-2020, over 131 houses located in fourteen rural communities in the northwest of Córdoba Province (central Argentina). We used generalized linear models to evaluate the effect of (i) the environmental anthropic disturbance in the study area, (ii) the composition and configuration of the landscape surrounding the house, (iii) the spatial arrangement of houses, (iv) and the availability of artificial refuges and domestic animals in the peridomicile, on house invasion by triatomines. We report the occurrence of seven species of triatomines invading rural houses in the study area -T. infestans, T. guasayana, T. garciabesi, T. platensis, T. delpontei, T. breyeri and P. guentheri-. Study data suggest that invasion by triatomines occurs with higher frequency in disturbed landscapes, with houses spatially isolated and in proximity to subdivided fragments of forest. The availability of domestic refuges in the peridomestic structures as well as the presence of a higher number of domestic animals increase the chances of invasion by triatomines.
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Affiliation(s)
- Miriam Cardozo
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Cátedra de Introducción a la Biología, Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT-CONICET), Córdoba, Argentina
| | - Federico Gastón Fiad
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Cátedra de Introducción a la Biología, Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT-CONICET), Córdoba, Argentina
| | - Liliana Beatríz Crocco
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Cátedra de Introducción a la Biología, Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT-CONICET), Córdoba, Argentina
| | - David Eladio Gorla
- Universidad Nacional de Córdoba, Grupo de Ecología y Control de Vectores, Instituto de Diversidad y Ecología Animal (IDEA- CONICET), Córdoba, Argentina
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Cardinal MV, Enriquez GF, Macchiaverna NP, Argibay HD, Fernández MDP, Alvedro A, Gaspe MS, Gürtler RE. Long-term impact of a ten-year intervention program on human and canine Trypanosoma cruzi infection in the Argentine Chaco. PLoS Negl Trop Dis 2021; 15:e0009389. [PMID: 33979344 PMCID: PMC8115854 DOI: 10.1371/journal.pntd.0009389] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 04/13/2021] [Indexed: 12/18/2022] Open
Abstract
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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Affiliation(s)
- Marta Victoria Cardinal
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
- * E-mail:
| | - Gustavo Fabián Enriquez
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - Natalia Paula Macchiaverna
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - Hernán Darío Argibay
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - María del Pilar Fernández
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
- Paul G. Allen School for Global Health, Washington State University, Pullman, Washington, United States for America
| | - Alejandra Alvedro
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - María Sol Gaspe
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - Ricardo Esteban Gürtler
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
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Rodríguez-Planes LI, Gaspe MS, Enriquez GF, Gürtler RE. Impacts of residual insecticide spraying on the abundance and habitat occupancy of Triatoma sordida and co-occurrence with Triatoma infestans: A three-year follow-up in northeastern Argentina. Acta Trop 2020; 202:105251. [PMID: 31706862 DOI: 10.1016/j.actatropica.2019.105251] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 10/17/2019] [Accepted: 10/30/2019] [Indexed: 11/28/2022]
Abstract
Triatoma infestans, the main vector in the Gran Chaco region, may competitively displace other sympatric species such as Triatoma sordida. We conducted a three-year longitudinal study of site- and house-level infestation and abundance of triatomine bugs before and after an area-wide insecticide spraying campaign followed by sustained vector surveillance in a well-defined rural section of the Argentine Chaco encompassing 368-411 houses. Here, we tested whether insecticide applications targeting and virtually suppressing T. infestans reduced the abundance of T. sordida and modified its habitat occupancies, and whether their joint spatial distribution was random, aggregated or uniform, and varied over time. Systematic timed-manual searches of 18,031 sites yielded 2,226 T. sordida over seven postintervention surveys. Triatoma sordida failed to colonize human sleeping quarters after interventions, and its prime and secondary habitats remained virtually unmodified. Residual insecticide spraying and seasonality best described variations in the house-level abundance of T. sordida as determined using a generalized estimating equation model. Two-species foci occurred in 3.2% of sites ever positive for any species. The habitat-adjusted relative odds of catching one species was 10.8 times greater when the other species was present, with no evidence of heterogeneity among ORs, suggesting no antagonistic interactions throughout the follow-up. The spatial occurrence of both species was significantly aggregated within 300-500 m before and after interventions, and was random at broader spatial scales. The habitat occupancies of T. sordida may be used as a proxy for potential infestation with T. infestans and to guide targeted vector control actions.
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Affiliation(s)
- Lucía I Rodríguez-Planes
- Universidad de Buenos Aires. Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; Universidad Nacional de Tierra del Fuego, Onas 450, Ushuaia 9410, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias Polares, Ambiente y Recursos Naturales, Onas 450, Ushuaia 9410, Argentina
| | - M Sol Gaspe
- Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Gustavo F Enriquez
- Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Ricardo E Gürtler
- Universidad de Buenos Aires. Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina.
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Human infectiousness and parasite load in chronic patients seropositive for Trypanosoma cruzi in a rural area of the Argentine Chaco. INFECTION GENETICS AND EVOLUTION 2019; 78:104062. [PMID: 31683004 DOI: 10.1016/j.meegid.2019.104062] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/28/2019] [Accepted: 10/02/2019] [Indexed: 12/25/2022]
Abstract
A key parameter in the transmission of vector-borne infections, including Chagas disease, is the ability of the different host species to transmit the parasite to the vector (infectiousness). Here, we determined infectiousness to the vector of Trypanosoma cruzi-seropositive humans examined by artificial xenodiagnosis (XD), established its relationship with T. cruzi DNA levels (a surrogate of intensity of parasitemia) quantified by real-time PCR (qPCR), and assessed whether infectiousness was associated with the body mass index (BMI), age, ethnic background and parasite genotype. XD was performed to 117 T. cruzi-seropositive residents from Pampa del Indio and parasite load was quantified in 81 of them. Using optical microscopy (OM) 33.6% of the seropositive people tested were infectious and this fraction nearly doubled (66.0%) when XD triatomines were examined by kDNA-PCR. The mean infectiousness (defined as the percentage of all infected triatomines detected by OM at any time point among the total number of insects examined by OM 30 days post-feeding) was 5.2%, and the mean parasite load was 0.51 parasite equivalents per ml. Infectiousness to the vector was associated negatively with age and BMI, and positively with the detection of parasitemia by kDNA-PCR, and parasite load by qPCR in bivariate analysis. Patients with a positive XD by OM exhibited a significantly higher mean parasite load. Using multiple regression, infectiousness was associated with parasite load (positively) and with the household presence of T. infestans and Qom ethnic group (negatively); no significant association was observed with age or its interaction with ethnicity. We did not find significant associations between identified DTUs and infectiousness or parasite load. Infectiousness was aggregated: 18% of the people examined by XD generated 80% of the infected triatomines. Detecting and treating the super-infectious fraction of the infected human would disproportionally impact on domestic transmission risks. Nonetheless, treatment of all eligible infected people who meet the inclusion criteria regardless of their parasitemia should be ensured to improve their prognosis.
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Murphy N, Macchiaverna NP, Victoria Cardinal M, Bhattacharyya T, Mertens P, Zeippen N, Gustin Y, Gilleman Q, Gürtler RE, Miles MA. Lineage-specific rapid diagnostic tests can resolve Trypanosoma cruzi TcII/V/VI ecological and epidemiological associations in the Argentine Chaco. Parasit Vectors 2019; 12:424. [PMID: 31522683 PMCID: PMC6746045 DOI: 10.1186/s13071-019-3681-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 08/22/2019] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Trypanosoma cruzi, the protozoan agent of Chagas disease, is comprised of at least 6 genetic lineages (TcI-TcVI). Their geographical distribution, clinical associations and reservoir hosts are not fully elucidated, as genotyping is hampered due to the difficulty in isolating representative populations of organisms. Lineage-specific serological techniques may address these issues. METHODS Trypanosoma cruzi lineage-specific serological assays were performed on human, canine, feline and armadillo sera from the Gran Chaco in northern Argentina, a region of ongoing transmission. Synthetic peptides representing lineage-specific epitopes of the trypomastigote small surface antigen (TSSA) were used in ELISA, and the TcII/V/VI shared epitope peptide (TSSApep-II/V/VI) was used in the Chagas Sero K-SeT rapid diagnostic test (RDT). RESULTS Chagas Sero K-SeT RDT, using Protein G to detect human and canine IgG, was at least as sensitive as TSSApep-II/V/VI ELISA using specific secondary antibodies. For sera from humans TSSApep-II/V/VI seroprevalence by Chagas Sero K-SeT was 273/393 (69.5%), for dogs 48/73 (65.8%) and for armadillos 1/7 (14.3%); by ELISA for cats 5/19 (26.3%). The seroprevalence for humans was similar to that for Bolivian patients, amongst whom we previously observed an association of TSSApep-II/V/VI seropositivity with severity of cardiomyopathy. In humans, prevalence of TSSApep-II/V/VI recognition was associated with locality, and with increasing and decreasing age within the Qom and Creole populations, respectively. For dogs TSSApep-II/V/VI recognition was associated with being born before community-wide insecticide spraying (P = 0.05) and with Qom household (P < 0.001). CONCLUSIONS We show here that Chagas Sero K-SeT RDT can replace ELISA for TSSApep-II/V/VI serology of humans and dogs; for humans there were statistically significant associations between a positive Chagas Sero K-SeT RDT and being resident in Area IV, and for dogs association with Qom household or with being born before the mass spraying campaign; we also show that with cats the TcII/V/VI epitope can be detected by ELISA. We assessed the lineage distribution in an unprecedented 83% of the human T. cruzi-seropositive population. These results form the basis for more detailed studies, enabling rapid in-the-field surveillance of the distribution and clustering of these lineages among humans and mammalian reservoirs of T. cruzi infection.
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Affiliation(s)
- Niamh Murphy
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Natalia P. Macchiaverna
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exacta y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
| | - M. Victoria Cardinal
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exacta y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
| | - Tapan Bhattacharyya
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | | | | | | | | | - Ricardo E. Gürtler
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exacta y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
| | - Michael A. Miles
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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Dye-Braumuller KC, Gorchakov R, Gunter SM, Nielsen DH, Roachell WD, Wheless A, Debboun M, Murray KO, Nolan MS. Identification of Triatomines and Their Habitats in a Highly Developed Urban Environment. Vector Borne Zoonotic Dis 2019; 19:265-273. [PMID: 30571182 PMCID: PMC6459272 DOI: 10.1089/vbz.2018.2352] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Eleven triatomine species, the vector for Chagas disease, are endemic in the southern U.S. While traditionally thought to only occur in rural habitats and sylvatic transmission cycles, recent studies provide compounding evidence that triatomines could exist in urban habitats and domestic transmission cycles in Texas. We conducted a study of active and passive surveillance techniques over 3 years (2016-2018) in the City of Houston, Harris County, Texas to determine the presence of triatomines in this metroplex. Active surveillance methods uncovered Triatoma sanguisuga nymphs from two locations in downtown Houston city parks. We also documented the first Trypanosoma cruzi positive kissing bug collected in an urban environment of Harris County, Texas. Our findings provide evidence that triatomines can be found in heavily populated U.S. urban environments, and warrant public health support for expanded triatomine and Chagas disease surveillance in city settings.
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Affiliation(s)
| | - Rodion Gorchakov
- Section of Pediatric Tropical Medicine, Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas
| | - Sarah M. Gunter
- Section of Pediatric Tropical Medicine, Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas
| | - David H. Nielsen
- Public Health Command Central, JBSA-Fort Sam Houston, San Antonio, Texas
| | - Walter D. Roachell
- Public Health Command Central, JBSA-Fort Sam Houston, San Antonio, Texas
| | - Anna Wheless
- Section of Pediatric Tropical Medicine, Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas
| | - Mustapha Debboun
- Mosquito and Vector Control Division, Harris County Public Health, Houston, Texas
| | - Kristy O. Murray
- Section of Pediatric Tropical Medicine, Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas
| | - Melissa S. Nolan
- Section of Pediatric Tropical Medicine, Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas
- Department of Epidemiology, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina
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Spatio-temporal characterization of Trypanosoma cruzi infection and discrete typing units infecting hosts and vectors from non-domestic foci of Chile. PLoS Negl Trop Dis 2019; 13:e0007170. [PMID: 30768613 PMCID: PMC6395009 DOI: 10.1371/journal.pntd.0007170] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 02/28/2019] [Accepted: 01/17/2019] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Trypanosoma cruzi is a protozoan parasite that is transmitted by triatomine vectors to mammals. It is classified in six discrete typing units (DTUs). In Chile, domestic vectorial transmission has been interrupted; however, the parasite is maintained in non-domestic foci. The aim of this study was to describe T. cruzi infection and DTU composition in mammals and triatomines from several non-domestic populations of North-Central Chile and to evaluate their spatio-temporal variations. METHODOLOGY/PRINCIPAL FINDINGS A total of 710 small mammals and 1140 triatomines captured in six localities during two study periods (summer/winter) of the same year were analyzed by conventional PCR to detect kDNA of T. cruzi. Positive samples were DNA blotted and hybridized with specific probes for detection of DTUs TcI, TcII, TcV, and TcVI. Infection status was modeled, and cluster analysis was performed in each locality. We detected 30.1% of overall infection in small mammals and 34.1% in triatomines, with higher rates in synanthropic mammals and in M. spinolai. We identified infecting DTUs in 45 mammals and 110 triatomines, present more commonly as single infections; the most frequent DTU detected was TcI. Differences in infection rates among species, localities and study periods were detected in small mammals, and between triatomine species; temporally, infection presented opposite patterns between mammals and triatomines. Infection clustering was frequent in vectors, and one locality exhibited half of the 21 clusters found. CONCLUSIONS/SIGNIFICANCE We determined T. cruzi infection in natural host and vector populations simultaneously in a spatially widespread manner during two study periods. All captured species presented T. cruzi infection, showing spatial and temporal variations. Trypanosoma cruzi distribution can be clustered in space and time. These clusters may represent different spatial and temporal risks of transmission.
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Maintenance of Trypanosoma cruzi, T. evansi and Leishmania spp. by domestic dogs and wild mammals in a rural settlement in Brazil-Bolivian border. INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2018; 7:398-404. [PMID: 30370220 PMCID: PMC6199764 DOI: 10.1016/j.ijppaw.2018.10.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 09/30/2018] [Accepted: 10/13/2018] [Indexed: 11/05/2022]
Abstract
Domestic dogs are considered reservoirs hosts for several vector-borne parasites. This study aimed to evaluate the role of domestic dogs as hosts for Trypanosoma cruzi, Trypanosoma evansi and Leishmania spp. in single and co-infections in the Urucum settlement, near the Brazil-Bolivian border. Additionally, we evaluated the involvement of wild mammals’ in the maintenance of these parasites in the study area. Blood samples of dogs (n = 62) and six species of wild mammals (n = 36) were collected in July and August of 2015. The infections were assessed using parasitological, serological and molecular tests. Clinical examination of dogs was performed and their feeding habits were noted. Overall, 87% (54/62) of sampled dogs were positive for at least one trypanosomatid species, in single (n = 9) and co-infections (n = 45). We found that 76% of dogs were positive for T. cruzi, four of them displayed high parasitemias demonstrated by hemoculture, including one strain types TcI, two TcIII and one TcIII/TcV. Around 73% (45/62) of dogs were positive to T. evansi, three with high parasitemias as seen by positive microhematocrit centrifuge technique. Of dogs sampled, 50% (31/62) were positive for Leishmania spp. by PCR or serology. We found a positive influence of (i) T. evansi on mucous pallor, (ii) co-infection by T. cruzi and Leishmania with onychogryphosis, and (iii) all parasites to skin lesions of sampled dogs. Finally, feeding on wild mammals had a positive influence in the Leishmania spp. infection in dogs. We found that 28% (5/18) coati Nasua nasua was co-infected for all three trypanosamatids, demonstrating that it might play a key role in maintenance of these parasites. Our results showed the importance of Urucum region as a hotspot for T. cruzi, T. evansi and Leishmania spp. and demonstrated that dogs can be considered as incidental hosts. Observation of high occurrence of dogs co-infected by trypanosomatids. Dogs infected by TcI, TcIII and TcIII/TcV. Nasua nasua is a key species in the sylvatic cycles of trypanosomatids. Direct effect of trypanosomatids' infection in clinical signs of dogs. Dogs as sentinels to human infection in the Brazil-Bolivian border.
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Macchiaverna NP, Enriquez GF, Buscaglia CA, Balouz V, Gürtler RE, Cardinal MV. New human isolates of Trypanosoma cruzi confirm the predominance of hybrid lineages in domestic transmission cycle of the Argentinean Chaco. INFECTION GENETICS AND EVOLUTION 2018; 66:229-235. [PMID: 30296602 DOI: 10.1016/j.meegid.2018.10.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/01/2018] [Accepted: 10/01/2018] [Indexed: 12/20/2022]
Abstract
Trypanosoma cruzi, the etiological agent of Chagas disease, was initially classified into 6 Discrete Typing Units (DTUs). The hybrid DTUs TcV and TcVI are the most frequent in domestic transmission cycles throughout the Southern Cone countries of South America. Here, we genotyped parasite isolates from human residents in Pampa del Indio municipality, Chaco, to further characterize the structure of T. cruzi populations, and to assess the degree of overlapping between the domestic and sylvatic transmission cycles. Artificial xenodiagnostic tests were performed to blood samples from 125 T. cruzi-seropositive people (age range, 3-70 years) who represented 14.3% of all seropositive residents identified. Parasites were obtained from feces of T. cruzi-infected Triatoma infestans examined 30 or 60 days after blood-feeding, and grown in vitro. The cultured parasites were genotyped by means of two PCR-based protocols. DTUs were determined from 39 (31%) patients residing in 28 dwellings. The only DTUs identified were TcV (92%) and TcVI (8-36%). Households with more than one parasite isolate consistently displayed the same DTU. Further sequencing of a fragment of the TcMK gene from selected samples argue against the occurrence of mixed TcV-TcVI infections in the study population. Sequencing data revealed an unexpected degree of genetic variability within TcV including two apparently robust subgroups of isolates. Our results for human residents confirm the predominance of hybrid lineages (TcV and to a much lesser extent TcVI) and the absence of sylvatic genotypes (TcI and TcIII) in (peri)domestic transmission cycles in the Argentinean Chaco area. 245 words.
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Affiliation(s)
- Natalia Paula Macchiaverna
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires e Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), UBA-CONICET, Capital Federal, Argentina
| | - Gustavo Fabián Enriquez
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires e Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), UBA-CONICET, Capital Federal, Argentina
| | - Carlos Andrés Buscaglia
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECh), Universidad Nacional de San Martín (UNSAM) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Virginia Balouz
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECh), Universidad Nacional de San Martín (UNSAM) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Ricardo Esteban Gürtler
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires e Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), UBA-CONICET, Capital Federal, Argentina
| | - Marta Victoria Cardinal
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires e Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), UBA-CONICET, Capital Federal, Argentina.
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Gaspe MS, Provecho YM, Fernández MP, Vassena CV, Santo Orihuela PL, Gürtler RE. Beating the odds: Sustained Chagas disease vector control in remote indigenous communities of the Argentine Chaco over a seven-year period. PLoS Negl Trop Dis 2018; 12:e0006804. [PMID: 30278044 PMCID: PMC6168123 DOI: 10.1371/journal.pntd.0006804] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 08/29/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Rapid reinfestation of insecticide-treated dwellings hamper the sustained elimination of Triatoma infestans, the main vector of Chagas disease in the Gran Chaco region. We conducted a seven-year longitudinal study including community-wide spraying with pyrethroid insecticides combined with periodic vector surveillance to investigate the house reinfestation process in connection with baseline pyrethroid resistance, housing quality and household mobility in a rural section of Pampa del Indio mainly inhabited by deprived indigenous people (Qom). METHODOLOGY/PRINCIPAL FINDINGS Despite evidence of moderate pyrethroid resistance in local T. infestans populations, house infestation dropped from 31.9% at baseline to 0.7% at 10 months post-spraying (MPS), with no triatomine found at 59 and 78 MPS. Household-based surveillance corroborated the rare occurrence of T. infestans and the house invasion of other four triatomine species. The annual rates of loss of initially occupied houses and of household mobility were high (4.6-8.0%). Housing improvements did not translate into a significant reduction of mud-walled houses and refuges for triatomines because most households kept the former dwelling or built new ones with mud walls. CONCLUSIONS/SIGNIFICANCE Our results refute the assumption that vector control actions performed in marginalized communities of the Gran Chaco are doomed to fail. The larger-than-expected impacts of the intervention program were likely associated with the combined effects of high-coverage, professional insecticide spraying followed by systematic vector surveillance-and-response, broad geographic coverage creating a buffer zone, frequent housing replacement and residential mobility. The dynamical interactions among housing quality, mobility and insecticide-based control largely affect the chances of vector elimination.
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Affiliation(s)
- M. Sol Gaspe
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Laboratorio de Eco-Epidemiología, Ciudad Universitaria, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, Buenos Aires, Argentina
| | - Yael M. Provecho
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Laboratorio de Eco-Epidemiología, Ciudad Universitaria, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, Buenos Aires, Argentina
- Coordinación de Vectores, Dirección Nacional de Epidemiología y Análisis de la Situación de Salud, Ministerio de Salud de la Nación, Buenos Aires, Argentina
| | - María P. Fernández
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Laboratorio de Eco-Epidemiología, Ciudad Universitaria, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, Buenos Aires, Argentina
- Earth Institute, Columbia University, New York, New York, United States of America
| | - Claudia V. Vassena
- Centro de Investigaciones de Plagas e Insecticidas (UNIDEF, CITEDEF, CONICET, CIPEIN), Buenos Aires, Argentina
- Cátedra de Química Analítica Instrumental, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Pablo L. Santo Orihuela
- Centro de Investigaciones de Plagas e Insecticidas (UNIDEF, CITEDEF, CONICET, CIPEIN), Buenos Aires, Argentina
- Departamento de Investigación e Ingeniería Ambiental (3iA), Universidad Nacional de San Martín, Buenos Aires, Argentina
| | - Ricardo E. Gürtler
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Laboratorio de Eco-Epidemiología, Ciudad Universitaria, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, Buenos Aires, Argentina
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Rodríguez IG, Saldaña A, González K, Pineda V, Perea M, Santamaría AM, de Junca CC, Chaves LF, Calzada JE. Trypanosoma cruzi Infection in Rhodnius pallescens (Heteroptera: Reduviidae) Infesting Coyol Palms in the Dry Arch of Panamá. JOURNAL OF MEDICAL ENTOMOLOGY 2018; 55:691-700. [PMID: 29425363 DOI: 10.1093/jme/tjx249] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Indexed: 06/08/2023]
Abstract
Ecoepidemiological scenarios for Trypanosoma cruzi Chagas transmission are partially shaped by kissing bug vector ecology. The presence of Attalea butyracea Kunth, the 'royal palm', is a major risk factor for Chagas disease transmission in Panamá given their frequent infestations by Rhodnius pallescens Barber, a major neotropical T. cruzi vector. It was assumed that in Panamá this relationship was very close and unique, limiting the niche of R. pallescens to that of Att. butyracea. However, here we present observations about T. cruzi-infected R. pallescens infesting coyol palms, Acrocomia aculeata Jacquin, in Pedasí district, Los Santos Province, Panamá. Between May 2015 and August 2016, we sampled kissing bugs from 83 coyol palms using mice-baited traps placed at the crown of each palm during the dry and wet season. We collected 62 R. pallescens and one Eratyrus cuspidatus Stål kissing bugs. Using logistic regression, we found that the probability of kissing bug infestation in coyol palms increased during the rainy season, with infructescence number and palm height. We examined adult R. pallescens bugs (n = 30) and found T. cruzi in 67% of the samples. We were able to isolate and characterize T. cruzi from parasites present in the feces from R. pallescens, all parasites belonging to the TC I lineage. We found that green fronds number and house proximity increased T. cruzi infection probability in kissing bugs collected in coyol palms. These results highlight coyol palms as a potential risk factor for Chagas disease transmission in the dry arch of Panamá.
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Affiliation(s)
- Indra G Rodríguez
- Programa Centroamericano de Maestría en Entomología, Universidad de Panamá, Ciudad de Panamá, República de Panamá
| | - Azael Saldaña
- Departamento de Investigación en Parasitología, Instituto Gorgas de Estudios de la Salud (ICGES), Ciudad de Panamá, República de Panamá
- Centro de Investigación y Diagnóstico de Enfermedades Parasitarias (CIDEP), Facultad de Medicina, Universidad de Panamá, Panamá
| | - Kadir González
- Departamento de Investigación en Parasitología, Instituto Gorgas de Estudios de la Salud (ICGES), Ciudad de Panamá, República de Panamá
| | - Vanessa Pineda
- Departamento de Investigación en Parasitología, Instituto Gorgas de Estudios de la Salud (ICGES), Ciudad de Panamá, República de Panamá
| | - Milixa Perea
- Departamento de Investigación en Parasitología, Instituto Gorgas de Estudios de la Salud (ICGES), Ciudad de Panamá, República de Panamá
| | - Ana M Santamaría
- Departamento de Investigación en Parasitología, Instituto Gorgas de Estudios de la Salud (ICGES), Ciudad de Panamá, República de Panamá
| | - Carmen C de Junca
- Centro de Investigación y Diagnóstico de Enfermedades Parasitarias (CIDEP), Facultad de Medicina, Universidad de Panamá, Panamá
| | - Luis F Chaves
- Programa de Investigación en Enfermedades Tropicales (PIET), Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - José E Calzada
- Departamento de Investigación en Parasitología, Instituto Gorgas de Estudios de la Salud (ICGES), Ciudad de Panamá, República de Panamá
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Piccinali RV, Gaunt MW, Gürtler RE. A Microsatellite-Based Analysis of House Infestation With Triatoma Infestans (Hemiptera: Reduviidae) After Insecticide Spraying in the Argentine Chaco. JOURNAL OF MEDICAL ENTOMOLOGY 2018; 55:609-619. [PMID: 29385501 DOI: 10.1093/jme/tjx256] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Indexed: 06/07/2023]
Abstract
Prevention of vector-borne transmission of Chagas disease mainly relies on residual insecticide spraying. Despite significant success at a regional scale, house infestation with Triatoma infestans (Klug) (Hemiptera: Reduviidae) still persists in the Gran Chaco ecoregion. One key aspect is the identification of the sources of reinfestant triatomines. After detecting fine-scale genetic structure in two rural villages of Pampa del Indio, Argentine Chaco, we tested hypotheses on the putative origins of the triatomines collected at 4, 8, and 12 mo after insecticide house spraying. We genotyped 10 microsatellite loci in 262 baseline and 83 postspraying triatomines from different houses. Genetic variability was similar between baseline and postspraying populations, but 13 low-frequency alleles were not detected at postspraying. FSTs were not significant between insects collected before and after insecticide spraying at the same house in all but one case, and they clustered together in a neighbor-joining tree. A clustering algorithm detected seven genetic groups, four of them mainly composed of baseline and postspraying insects from the same house. Assignment tests suggested multiple putative sources (including the house of collection) for most postspraying insects but excluded a house located more than 9 km from the study area. The origin of three triatomines was attributed to immigration from other unaccounted sources. Our study is compatible with the hypothesis that house reinfestations in the Argentine Chaco are mostly related to residual foci (i.e., survival of insects within the same community), in agreement with field observations, spatial analysis, and morphometric studies previously published.
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Affiliation(s)
- Romina V Piccinali
- Facultad de Ciencias Exactas y Naturales, Departamento de Ecología, Genética y Evolución, Laboratorio de Eco-Epidemiología Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
- Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), CONICET-Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Michael W Gaunt
- Infectious and Tropical Diseases Department, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Ricardo E Gürtler
- Facultad de Ciencias Exactas y Naturales, Departamento de Ecología, Genética y Evolución, Laboratorio de Eco-Epidemiología Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
- Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), CONICET-Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
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Rodríguez-Planes LI, Gaspe MS, Enriquez GF, Gürtler RE. Habitat-Specific Occupancy and a Metapopulation Model of Triatoma sordida (Hemiptera: Reduviidae), a Secondary Vector of Chagas Disease, in Northeastern Argentina. JOURNAL OF MEDICAL ENTOMOLOGY 2018; 55:370-381. [PMID: 29272421 DOI: 10.1093/jme/tjx227] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Indexed: 06/07/2023]
Abstract
Triatoma sordida Stål (Hemiptera: Reduviidae), a secondary vector of Trypanosoma cruzi Chagas (Kinetoplastida: Trypanosomatidae), occasionally colonizes human sleeping quarters in Paraguay, Bolivia, and Brazil, whereas only sylvatic and peridomestic populations are found in Argentina. We carried out a cross-sectional survey of house infestation in a well-defined rural area of northeastern Argentina to identify the key habitats of T. sordida; describe its spatial distribution in an apparently undisturbed setting under no recent insecticide treatment and use metapopulation theory to investigate these spatially structured populations. Timed-manual searches in 2,177 georeferenced sites from 368 houses yielded T. sordida in 78 sites (house infestation prevalence, 19.9%). Most triatomines occurred in chicken nests, chicken coops, and trees where chickens roosted (prime habitats). Goat or sheep corrals and pig corrals had a lower fraction of occupied sites (occupancies) and abundance. Both occupancy and catch increased with increasing refuge availability according to multimodel inference with model averaging. The majority of suitable habitats were unoccupied despite their proximity to occupied sites. The site-specific occurrence of T. sordida and Triatoma infestans Klug (Hemiptera: Reduviidae) was positively and homogeneously associated over ecotopes, showing no evidence of interspecific interference. An incidence function metapopulation model (including intersite distances and vector carrying capacity) predicted a fivefold greater occupancy relative to the observed pattern, suggesting the latter represented a transient state. T. sordida failed to colonize human sleeping quarters, thrived in peridomestic habitats occupied by chickens, and had a limited occupancy likely related to a poor colonizing ability and the relative instability of its prime habitats.
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Affiliation(s)
- Lucía I Rodríguez-Planes
- Universidad de Buenos Aires, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, Argentina
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, Argentina
| | - M Sol Gaspe
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, Argentina
| | - Gustavo F Enriquez
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, Argentina
| | - Ricardo E Gürtler
- Universidad de Buenos Aires, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, Argentina
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, Argentina
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ACOSTA NIDIA, LÓPEZ ELSA, LEWIS MICHAELD, LLEWELLYN MARTINS, GÓMEZ ANA, ROMÁN FABIOLA, MILES MICHAELA, YEO MATTHEW. Hosts and vectors of Trypanosoma cruzi discrete typing units in the Chagas disease endemic region of the Paraguayan Chaco. Parasitology 2017; 144:884-898. [PMID: 28179034 PMCID: PMC5471830 DOI: 10.1017/s0031182016002663] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 12/16/2016] [Accepted: 12/19/2016] [Indexed: 12/29/2022]
Abstract
Active Trypanosoma cruzi transmission persists in the Gran Chaco region, which is considered hyperendemic for Chagas disease. Understanding domestic and sylvatic transmission cycles and therefore the relationship between vectors and mammalian hosts is crucial to designing and implementing improved effective control strategies. Here we describe the species of triatomine vectors and the sylvatic mammal reservoirs of T. cruzi, in different localities of the Paraguayan and Bolivian Chaco. We identify the T. cruzi genotypes discrete typing units (DTUs) and provide a map of their geographical distribution. A total of 1044 triatomines and 138 sylvatic mammals were captured. Five per cent of the triatomines were microscopically positive for T. cruzi (55 Triatoma infestans from Paraguay and one sylvatic Triatoma guasayana from Bolivia) and 17 animals (12·3%) comprising eight of 28 (28·5%) Dasypus novemcinctus, four of 27 (14·8%) Euphractus sexcinctus, three of 64 (4·7%) Chaetophractus spp. and two of 14 (14·3%) Didelphis albiventris. The most common DTU infecting domestic triatomine bugs was TcV (64%), followed by TcVI (28%), TcII (6·5%) and TcIII (1·5%). TcIII was overwhelmingly associated with armadillo species. We confirm the primary role of T. infestans in domestic transmission, armadillo species as the principal sylvatic hosts of TcIII, and consider the potential risk of TcIII as an agent of Chagas disease in the Chaco.
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Affiliation(s)
- NIDIA ACOSTA
- Departamento de Medicina Tropical, Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción – UNA, San Lorenzo CP 2160, Paraguay
| | - ELSA LÓPEZ
- Departamento de Medicina Tropical, Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción – UNA, San Lorenzo CP 2160, Paraguay
| | - MICHAEL D. LEWIS
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - MARTIN S. LLEWELLYN
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - ANA GÓMEZ
- Centro para el Desarrollo de la Investigación Científica (CEDIC)/Díaz Gill Medicina Laboratorial/Fundación Moisés Bertoni, Asunción, Paraguay
| | - FABIOLA ROMÁN
- Centro para el Desarrollo de la Investigación Científica (CEDIC)/Díaz Gill Medicina Laboratorial/Fundación Moisés Bertoni, Asunción, Paraguay
| | - MICHAEL A. MILES
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - MATTHEW YEO
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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Provecho YM, Gaspe MS, Fernández MDP, Gürtler RE. House Reinfestation With Triatoma infestans (Hemiptera: Reduviidae) After Community-Wide Spraying With Insecticides in the Argentine Chaco: A Multifactorial Process. JOURNAL OF MEDICAL ENTOMOLOGY 2017; 54:646-657. [PMID: 28399199 DOI: 10.1093/jme/tjw224] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/29/2016] [Indexed: 06/07/2023]
Abstract
We investigated the dynamics and underlying causes of house (re)infestation with Triatoma infestans (Klug 1834) after a community-wide residual spraying with pyrethroids in a well-defined rural section of Pampa del Indio municipality (northeastern Argentina) over a 4-yr period. House infestation was assessed by timed manual searches, during insecticide applications, and by opportunistic householders' bug collections. All reinfested houses were selectively re-sprayed with insecticides. The resident population comprised Qom (66.6%) and Creole (33.4%) households, whose sociodemographic profiles differed substantially. The prevalence of house infestation dropped, less than expected, from 20.5% at baseline to 5.0% at 14 months postspraying (MPS), and then fluctuated between 0.8 and 4.2% over 21-51 MPS. Postspraying house infestation was positively and highly significantly associated with prespraying infestation. Most of the foci detected over 14-21 MPS were considered persistent (residual), some of which were moderately resistant to pyrethroids and were suppressed with malathion. Infestation patterns over 27-51 MPS suggested bug invasion from internal or external foci, but the sources of most findings were unaccounted for. Local spatial analysis identified two hotspots of postspraying house infestation. Using multimodel inference with model averaging, we corroborated that baseline domestic infestation was closely related to refuge availability, housing quality, and occurrence of peridomestic infestation. The diminished effectiveness of single pyrethroid treatments, partly attributable to moderate resistance compounded with rather insensitive vector detection methods and poor housing conditions, contributed to vector persistence. Improved control strategies combined with broad social participation are needed for the sustainable elimination of vector-borne human Chagas disease from the Gran Chaco.
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Affiliation(s)
- Yael M Provecho
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina (; ; ; )
| | - M Sol Gaspe
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina (; ; ; )
| | - M Del Pilar Fernández
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina (; ; ; )
| | - Ricardo E Gürtler
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina (; ; ; )
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20
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Ribeiro AR, Oliveira RCD, Ceretti Junior W, Lima L, Almeida LAD, Nascimento JD, Teixeira MMG, Rosa JAD. Trypanosoma cruzi isolated from a triatomine found in one of the biggest metropolitan areas of Latin America. Rev Soc Bras Med Trop 2016; 49:183-9. [PMID: 27192587 DOI: 10.1590/0037-8682-0366-2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 04/08/2016] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION To characterize Trypanosoma cruzi (TcI) isolated from a Panstrongylus megistus specimen found in one of the biggest metropolitan areas of Latin America, the relationship between the TcI group of T. cruzi and the transmission cycle in the urban environment was studied. METHODS The T. cruzi strain, Pm, was isolated in a culture medium from the evolutionary forms present in the hindgut of a live male specimen of P. megistus found in the Jabaquara subway in São Paulo City. The sample from the triatomine showed trypomastigote forms of Trypanosomatidae, which were inoculated in the peritoneum of Balb/c mice. The sample was then inoculated in Liver Infusion Tryptose medium and J774 cells for the molecular identification and characterization of the parasite. The Pm strain of T. cruzi was identified by isolation in axenic culture medium, and based on the morphology, cell infection, growth kinetics, and molecular characterization. RESULTS After isolation, the protozoan was identified as T. cruzi. No parasites were detected in the peripheral blood of the animal, which can be a characteristic inherent to the strain of T. cruzi that was isolated. Cell invasion assays were performed in triplicate in the J774 cell line to confirm the invasive ability of the Pm strain and revealed amastigote forms of the parasite within macrophages. CONCLUSIONS Our biological and molecular characterizations helped understand parasite-host interactions and their evolutionary history in context of the associations between vectors, ecotopes, hosts, and groups of the parasite.
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Affiliation(s)
- Aline Rimoldi Ribeiro
- Departamento de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil
| | | | | | - Luciana Lima
- Departamento de Parasitologia, Universidade de São Paulo, São Paulo, Brazil
| | - Larissa Aguiar de Almeida
- Departamento de Ciências Biológicas, Universidade Estadual Paulista Júlio de Mesquita Filho, Araraquara, São Paulo, Brazil
| | | | | | - João Aristeu da Rosa
- Departamento de Ciências Biológicas, Universidade Estadual Paulista Júlio de Mesquita Filho, Araraquara, São Paulo, Brazil
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First finding of Trypanosoma cruzi II in vampire bats from a district free of domestic vector-borne transmission in Northeastern Argentina. Parasitology 2016; 143:1358-68. [PMID: 27220254 DOI: 10.1017/s0031182016000925] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Establishing the putative links between sylvatic and domestic transmission cycles of Trypanosoma cruzi, the etiological agent of Chagas disease, is of public health relevance. We conducted three surveys to assess T. cruzi infection in wild mammals from a rural and a preserved area in Misiones Province, Northeastern Argentina, which had recently been declared free of vector- and blood-borne transmission of human T. cruzi infection. A total of 200 wild mammals were examined by xenodiagnosis (XD) and/or polymerase chain reaction (PCR) amplification of the hyper-variable region of kinetoplast DNA minicircles of T. cruzi (kDNA-PCR). The overall prevalence of T. cruzi infection was 8%. Nine (16%) of 57 Didelphis albiventris opossums and two (7%) of 29 Desmodus rotundus vampire bats were positive by both XD and kDNA-PCR. Additionally, one D. rotundus positive for T. cruzi by kDNA-PCR tested positive by satellite-DNA-PCR (SAT-DNA-PCR). The T. cruzi-infected bats were captured indoors and in the yard of a vacant dwelling. All D. albiventris were infected with TcI and both XD-positive D. rotundus by TcII. Fifty-five opossum cubs within the marsupium were negative by XD. The mean infectiousness to the vector was 62% in D. albiventris and 50% in D. rotundus. Mice experimentally infected with a parasite isolate from a vampire bat displayed lesions typically caused by T. cruzi. Our study documents the presence of the genotype TcII in a sylvatic host for the first time in Argentina, and the occurrence of two transmission cycles of T. cruzi in a district free of domestic vector-borne transmission.
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Neumann ADS, Dias FDA, Ferreira JDS, Fontes ANB, Rosa PS, Macedo RE, Oliveira JH, Teixeira RLDF, Pessolani MCV, Moraes MO, Suffys PN, Oliveira PL, Sorgine MHF, Lara FA. Experimental Infection of Rhodnius prolixus (Hemiptera, Triatominae) with Mycobacterium leprae Indicates Potential for Leprosy Transmission. PLoS One 2016; 11:e0156037. [PMID: 27203082 PMCID: PMC4874629 DOI: 10.1371/journal.pone.0156037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/09/2016] [Indexed: 11/16/2022] Open
Abstract
Leprosy is a chronic dermato-neurological disease caused by infection with Mycobacterium leprae. In 2013 almost 200,000 new cases of leprosy were detected around the world. Since the first symptoms take from years to decades to appear, the total number of asymptomatic patients is impossible to predict. Although leprosy is one of the oldest records of human disease, the mechanisms involved with its transmission and epidemiology are still not completely understood. In the present work, we experimentally investigated the hypothesis that the mosquitoes Aedes aegypti and Culex quinquefasciatus and the hemiptera Rhodnius prolixus act as leprosy vectors. By means of real-time PCR quantification of M. leprae 16SrRNA, we found that M. leprae remained viable inside the digestive tract of Rhodnius prolixus for 20 days after oral infection. In contrast, in the gut of both mosquito species tested, we were not able to detect M. leprae RNA after a similar period of time. Inside the kissing bug Rhodnius prolixus digestive tract, M. leprae was initially restricted to the anterior midgut, but gradually moved towards the hindgut, in a time course reminiscent of the life cycle of Trypanosoma cruzi, a well-known pathogen transmitted by this insect. The maintenance of M. leprae infectivity inside the digestive tract of this kissing bug is further supported by successful mice footpad inoculation with feces collected 20 days after infection. We conclude that Rhodnius prolixus defecate infective M. leprae, justifying the evaluation of the presence of M. leprae among sylvatic and domestic kissing bugs in countries endemic for leprosy.
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Affiliation(s)
- Arthur da Silva Neumann
- Laboratório de Microbiologia Celular, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Felipe de Almeida Dias
- Laboratório de Bioquímica de Artrópodes Hematófagos, Federal University of Rio de Janeiro, Rio de Janiero, Brazil
| | - Jéssica da Silva Ferreira
- Laboratório de Microbiologia Celular, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Amanda Nogueira Brum Fontes
- Laboratório de Biologia Molecular Aplicada a Micobactérias, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | | | - Rafael Enrique Macedo
- Laboratório de Microbiologia Celular, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - José Henrique Oliveira
- Laboratório de Bioquímica de Artrópodes Hematófagos, Federal University of Rio de Janeiro, Rio de Janiero, Brazil
| | | | | | - Milton Ozório Moraes
- Laboratório de Hanseníase, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Philip Noel Suffys
- Laboratório de Biologia Molecular Aplicada a Micobactérias, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Pedro L. Oliveira
- Laboratório de Bioquímica de Artrópodes Hematófagos, Federal University of Rio de Janeiro, Rio de Janiero, Brazil
| | | | - Flavio Alves Lara
- Laboratório de Microbiologia Celular, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- * E-mail:
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Cecere MC, Leporace M, Fernández MP, Zárate JE, Moreno C, Gürtler RE, Cardinal MV. Host-Feeding Sources and Infection With Trypanosoma cruzi of Triatoma infestans and Triatoma eratyrusiformis (Hemiptera: Reduviidae) From the Calchaqui Valleys in Northwestern Argentina. JOURNAL OF MEDICAL ENTOMOLOGY 2016; 53:666-673. [PMID: 26849898 DOI: 10.1093/jme/tjw002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 01/11/2016] [Indexed: 06/05/2023]
Abstract
We assessed the prevalence of infection with Trypanosoma cruzi, parasite genotypes (discrete typing units, DTUs), and the host-feeding sources of domestic and peridomestic Triatoma infestans Klug and Triatoma eratyrusiformis Del Ponte in eight rural communities of the subandean Calchaqui valleys in northwestern Argentina. We sought to analyze their epidemiological role in the context of routine vector surveillance and control actions. Infection with T. cruzi was determined by optic microscopy or polymerase chain reaction (PCR) amplification of the hypervariable region of kinetoplast DNA minicircles. Parasite genotypes were identified through a multi PCR-based strategy. Bloodmeal contents were tested with a direct ELISA assay against nine antisera. Human sleeping quarters (domiciles) and peridomestic dry-shrub fences concentrated most of the T. infestans and T. eratyrusiformis infected with T. cruzi, respectively. The most frequent host-feeding sources of T. infestans were chickens (73.1%) in peridomiciles and humans (73.3%) in domiciles, whereas T. eratyrusiformis fed more often on cavid rodents (92.6%), which thrived in the dry-shrub fences. The main T. cruzi DTU identified in both vectors was T. cruzi I (TcI). Triatoma eratyrusiformis was implicated in the local circulation of TcI among cavies and perhaps mice, but infection with other typically domestic DTUs (TcVI and TcII/TcV/TcVI) indicated overlap between (peri)domestic transmission cycles in both vector species. Because dry-shrub fences were not targeted for routine insecticide spraying, they may act as sources of (peri)domestic reinfestation. Triatoma eratyrusiformis is an emergent secondary vector of T. cruzi and plays a significant role in the local transmission of T. cruzi.
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Affiliation(s)
- M C Cecere
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires-Instituto de Ecología, Genética y Evolución (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET),Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina (; ; ; ; ),
| | - M Leporace
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires-Instituto de Ecología, Genética y Evolución (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET),Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina (; ; ; ; )
- Laboratorio de Control de Vectores Entomológicos de Importancia Sanitaria (LaCVEIS), Fundación Barceló, Centeno y Rivadavia. Santo Tomé, Corrientes, Argentina, and
| | - M P Fernández
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires-Instituto de Ecología, Genética y Evolución (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET),Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina (; ; ; ; )
| | - J E Zárate
- Coordinación Nacional de Control de Vectores (CNCV), Italia 1971, San Miguel de Tucumán, Tucumán, Argentina (; )
| | - C Moreno
- Coordinación Nacional de Control de Vectores (CNCV), Italia 1971, San Miguel de Tucumán, Tucumán, Argentina (; )
| | - R E Gürtler
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires-Instituto de Ecología, Genética y Evolución (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET),Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina (; ; ; ; )
| | - M V Cardinal
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires-Instituto de Ecología, Genética y Evolución (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET),Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina (; ; ; ; )
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Rojas-Cortez M, Pinazo MJ, Garcia L, Arteaga M, Uriona L, Gamboa S, Mejía C, Lozano D, Gascon J, Torrico F, Monteiro FA. Trypanosoma cruzi-infected Panstrongylus geniculatus and Rhodnius robustus adults invade households in the Tropics of Cochabamba region of Bolivia. Parasit Vectors 2016; 9:158. [PMID: 26984679 PMCID: PMC4794895 DOI: 10.1186/s13071-016-1445-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 03/10/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND There are hardly any data available on the relationships between the parasite and the vector or regarding potential reservoirs involved in the natural transmission cycle of Trypanosoma cruzi in the Tropics of Cochabamba, Bolivia. Local families from communities were responsible for the capture of triatomine specimens, following a strategic methodology based on entomological surveillance with community participation developed by the National Chagas Programme of the Ministry of Health of Bolivia. FINDINGS We describe the collection of adult Panstrongylus geniculatus and Rhodnius robustus naturally infected with Trypanosoma cruzi from houses and from the hospital of Villa Tunari municipality. The flagellates found in the digestive tract of P. geniculatus belong to genetic lineages or DTUs TcI and TcIII, whereas only lineage DTU TcI was found in R. robustus. The detection of these vectors infected with T. cruzi reveals the vulnerability of local communities. CONCLUSION The results presented here highlight the risk of Chagas disease transmission in a region previously thought not to be endemic, indicating that the Tropics of Cochabamba should be placed under permanent entomological and epidemiological surveillance.
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Affiliation(s)
| | - Maria-Jesus Pinazo
- ISGlobal, Barcelona and Center for International Health Research (CRESIB), Hospital Clinic - Barcelona University, Barcelona, Spain
| | - Lineth Garcia
- Instituto de Investigaciones Médicas (IIBISMED), Facultad de Medicina, Universidad Mayor de San Simón, Cochabamba, Bolivia
| | - Mery Arteaga
- Fundación CEADES, Cochabamba, Bolivia.,ISGlobal, Barcelona and Center for International Health Research (CRESIB), Hospital Clinic - Barcelona University, Barcelona, Spain
| | | | | | | | | | - Joaquim Gascon
- ISGlobal, Barcelona and Center for International Health Research (CRESIB), Hospital Clinic - Barcelona University, Barcelona, Spain
| | | | - Fernando A Monteiro
- Laboratório de Epidemiologia e Sistemática Molecular, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil
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A comparative study of Trypanosoma cruzi infection in sylvatic mammals from a protected and a disturbed area in the Argentine Chaco. Acta Trop 2016; 155:34-42. [PMID: 26708994 DOI: 10.1016/j.actatropica.2015.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 12/13/2015] [Accepted: 12/14/2015] [Indexed: 11/24/2022]
Abstract
Understanding the complex epidemiology of Trypanosoma cruzi transmission cycles requires comparative studies in widely different environments. We assessed the occurrence of T. cruzi infection in sylvatic mammals, their infectiousness to the vector, and parasite genotypes in a protected area of the Argentine Chaco, and compared them with information obtained similarly in a nearby disturbed area. A total of 278 mammals from >23 species in the protected area were diagnosed for T. cruzi infection using xenodiagnosis, kDNA-PCR and nuclear satellite DNA-PCR (SAT) from blood samples. The relative abundance and species composition differed substantially between areas. Didelphis albiventris opossums were less abundant in the protected area; had a significantly lower body mass index, and a stage structure biased toward earlier stages. The capture of armadillos was lower in the protected area. The composite prevalence of T. cruzi infection across host species was significantly lower in the protected area (11.1%) than in the disturbed area (22.1%), and heterogeneous across species groups. The prevalence of infection in D. albiventris and Thylamys pusilla opossums was significantly lower in the protected area (nil for D. albiventris), whereas infection in sigmodontine rodents was three times higher in the protected area (17.5 versus 5.7%). Parasite isolates from the two xenodiagnosis-positive mammals (1 Dasypus novemcinctus and 1 Conepatus chinga) were typed as TcIII; both specimens were highly infectious to Triatoma infestans. Fat-tailed opossums, bats and rodents were kDNA-PCR-positive and xenodiagnosis-negative. Desmodus rotundus and Myotis bats were found infected with T. cruzi for the first time in the Gran Chaco.
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Dias JVL, Queiroz DRM, Martins HR, Gorla DE, Pires HHR, Diotaiuti L. Spatial distribution of triatomines in domiciles of an urban area of the Brazilian Southeast Region. Mem Inst Oswaldo Cruz 2016; 111:43-50. [PMID: 26814643 PMCID: PMC4727435 DOI: 10.1590/0074-02760150352] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 12/08/2015] [Indexed: 11/25/2022] Open
Abstract
Reports of triatomine infestation in urban areas have increased. We analysed the spatial distribution of infestation by triatomines in the urban area of Diamantina, in the state of Minas Gerais, Brazil. Triatomines were obtained by community-based entomological surveillance. Spatial patterns of infestation were analysed by Ripley's K function and Kernel density estimator. Normalised difference vegetation index (NDVI) and land cover derived from satellite imagery were compared between infested and uninfested areas. A total of 140 adults of four species were captured (100 Triatoma vitticeps, 25 Panstrongylus geniculatus, 8 Panstrongylus megistus, and 7 Triatoma arthurneivai specimens). In total, 87.9% were captured within domiciles. Infection by trypanosomes was observed in 19.6% of 107 examined insects. The spatial distributions ofT. vitticeps, P. geniculatus, T. arthurneivai, and trypanosome-positive triatomines were clustered, occurring mainly in peripheral areas. NDVI values were statistically higher in areas infested by T. vitticeps and P. geniculatus. Buildings infested by these species were located closer to open fields, whereas infestations of P. megistus and T. arthurneivai were closer to bare soil. Human occupation and modification of natural areas may be involved in triatomine invasion, exposing the population to these vectors.
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Affiliation(s)
- João Victor Leite Dias
- Fundação Oswaldo Cruz, Centro de Pesquisas René Rachou, Laboratório de
Triatomíneos e Epidemiologia da Doença de Chagas, Belo Horizonte, MG, Brasil
- Universidade Federal dos Vales do Jequitinhonha e Mucuri, Departamento
de Farmácia, Laboratório de Doenças Parasitárias, Diamantina, MG, Brasil
| | - Dimas Ramon Mota Queiroz
- Universidade Federal dos Vales do Jequitinhonha e Mucuri, Departamento
de Farmácia, Laboratório de Doenças Parasitárias, Diamantina, MG, Brasil
| | - Helen Rodrigues Martins
- Universidade Federal dos Vales do Jequitinhonha e Mucuri, Departamento
de Farmácia, Laboratório de Doenças Parasitárias, Diamantina, MG, Brasil
| | - David Eladio Gorla
- Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto
Multidisciplinario de Biología Vegetal, Córdoba, Argentina
| | - Herton Helder Rocha Pires
- Universidade Federal dos Vales do Jequitinhonha e Mucuri, Departamento
de Farmácia, Laboratório de Doenças Parasitárias, Diamantina, MG, Brasil
| | - Liléia Diotaiuti
- Fundação Oswaldo Cruz, Centro de Pesquisas René Rachou, Laboratório de
Triatomíneos e Epidemiologia da Doença de Chagas, Belo Horizonte, MG, Brasil
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da Costa AP, Costa FB, Soares HS, Ramirez DG, Mesquita ETKDC, Gennari SM, Marcili A. Trypanosoma cruzi and Leishmania infantum chagasi Infection in Wild Mammals from Maranhão State, Brazil. Vector Borne Zoonotic Dis 2015; 15:656-66. [PMID: 26501369 DOI: 10.1089/vbz.2015.1771] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Trypanosoma and Leishmania are obligate parasites that cause important diseases in human and domestic animals. Wild mammals are the natural reservoirs of these parasites, which are transmitted by hematophagous arthropods. The present study aimed to detect the natural occurrence of trypanosomatids through serological diagnosis, PCR of whole blood and blood culture (hemoculture), and phylogenetic relationships using small subunit ribosomal DNA (SSU rDNA), cytochrome b, and glycosomal glyceraldehyde 3-phosphate dehydrogenase (gGAPDH) genes. Samples from 131 wild animals, including rodents, marsupials, and bats, were sampled in six areas in the state of Maranhão, in a transition zone of semiarid climates northeast of the equatorial humid Amazon. Serological analysis for Leishmania (Leishmania) infantum chagasi was performed in opossums by indirect fluorescent antibody test (IFAT), and all animals were serologically negative. Nine positive hemocultures (6.77%) were isolated and cryopreserved and from mammals of the Didelphimorphia and Chiroptera orders and positioned in phylogenies on the basis of sequences from different genes with reference strains of Trypanosoma cruzi marinkellei and T. cruzi. From primary samples (blood and tissues) only one bat, Pteronotus parnellii, was positive to SSU rDNA and gGAPDH genes and grouped with the L. infantum chagasi branch. The studies conducted in Maranhão State provide knowledge of parasite diversity. It is important to determine the presence of trypanosomatids in wild mammals with synanthropic habits.
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Affiliation(s)
- Andréa Pereira da Costa
- 1 Departmento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo , São Paulo, SP, Brasil
| | - Francisco Borges Costa
- 1 Departmento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo , São Paulo, SP, Brasil
| | - Herbert Sousa Soares
- 1 Departmento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo , São Paulo, SP, Brasil
| | - Diego Garcia Ramirez
- 1 Departmento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo , São Paulo, SP, Brasil
| | | | - Solange Maria Gennari
- 1 Departmento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo , São Paulo, SP, Brasil
| | - Arlei Marcili
- 1 Departmento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo , São Paulo, SP, Brasil .,3 Medicina Veterinária e Bem estar animal-Universidade de Santo Amaro , SP, Brasil
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Castillo-Neyra R, Chou Chu L, Quispe-Machaca V, Ancca-Juarez J, Malaga Chavez FS, Bastos Mazuelos M, Naquira C, Bern C, Gilman RH, Levy MZ. The potential of canine sentinels for reemerging Trypanosoma cruzi transmission. Prev Vet Med 2015; 120:349-56. [PMID: 25962956 DOI: 10.1016/j.prevetmed.2015.04.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 03/23/2015] [Accepted: 04/22/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Chagas disease, a vector-borne disease transmitted by triatomine bugs and caused by the parasite Trypanosoma cruzi, affects millions of people in the Americas. In Arequipa, Peru, indoor residual insecticide spraying campaigns are routinely conducted to eliminate Triatoma infestans, the only vector in this area. Following insecticide spraying, there is risk of vector return and reinitiation of parasite transmission. Dogs are important reservoirs of T. cruzi and may play a role in reinitiating transmission in previously sprayed areas. Dogs may also serve as indicators of reemerging transmission. METHODS We conducted a cross-sectional serological screening to detect T. cruzi antibodies in dogs, in conjunction with an entomological vector collection survey at the household level, in a disease endemic area that had been treated with insecticide 13 years prior. Spatial clustering of infected animals and vectors was assessed using Ripley's K statistic, and the odds of being seropositive for dogs proximate to infected colonies was estimated with multivariate logistic regression. RESULTS There were 106 triatomine-infested houses (41.1%), and 45 houses infested with T. cruzi-infected triatomine insects (17.4%). Canine seroprevalence in the area was 12.3% (n=154); all seropositive dogs were 9 months old or older. We observed clustering of vectors carrying the parasite, but no clustering of seropositive dogs. The age- and sex-adjusted odds ratio between seropositivity to T. cruzi and proximity to an infected triatomine (≤50m) was 5.67 (95% CI: 1.12-28.74; p=0.036). CONCLUSIONS Targeted control of reemerging transmission can be achieved by improved understanding of T. cruzi in canine populations. Our results suggest that dogs may be useful sentinels to detect re-initiation of transmission following insecticide treatment. Integration of canine T. cruzi blood sampling into existing interventions for zoonotic disease control (e.g., rabies vaccination programs) can be an effective method of increasing surveillance and improving understanding of disease distribution.
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Affiliation(s)
- Ricardo Castillo-Neyra
- Center for Clinical Epidemiology & Biostatistics - Department of Biostatistics & Epidemiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA; Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru.
| | - Lily Chou Chu
- Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | - Jenny Ancca-Juarez
- Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | | | - Cesar Naquira
- Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Caryn Bern
- School of Medicine, University of California, San Francisco, CA, USA
| | - Robert H Gilman
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Michael Z Levy
- Center for Clinical Epidemiology & Biostatistics - Department of Biostatistics & Epidemiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA.
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León CM, Hernández C, Montilla M, Ramírez JD. Retrospective distribution of Trypanosoma cruzi I genotypes in Colombia. Mem Inst Oswaldo Cruz 2015; 110:387-93. [PMID: 25946157 PMCID: PMC4489476 DOI: 10.1590/0074-02760140402] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 02/25/2015] [Indexed: 12/03/2022] Open
Abstract
Trypanosoma cruzi is the aetiological agent of Chagas disease, which
affects approximately eight million people in the Americas. This parasite exhibits
genetic variability, with at least six discrete typing units broadly distributed in
the American continent. T. cruzi I (TcI) shows remarkable genetic
diversity; a genotype linked to human infections and a domestic cycle of transmission
have recently been identified, hence, this strain was named TcIDom. The aim of this
work was to describe the spatiotemporal distribution of TcI subpopulations across
humans, insect vectors and mammalian reservoirs in Colombia by means of molecular
typing targeting the spliced leader intergenic region of mini-exon gene. We analysed
101 TcI isolates and observed a distribution of sylvatic TcI in 70% and TcIDom in
30%. In humans, the ratio was sylvatic TcI in 60% and TcIDom in 40%. In mammal
reservoirs, the distribution corresponded to sylvatic TcI in 96% and TcIDom in 4%.
Among insect vectors, sylvatic TcI was observed in 48% and TcIDom in 52%. In
conclusion, the circulation of TcIDom is emerging in Colombia and this genotype is
still adapting to the domestic cycle of transmission. The epidemiological and
clinical implications of these findings are discussed herein.
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Affiliation(s)
- Cielo M León
- Red Chagas Colombia, Instituto Nacional de Salud, Bogotá, Colombia
| | | | - Marleny Montilla
- Grupo de Parasitología, Instituto Nacional de Salud, Bogotá, Colombia
| | - Juan David Ramírez
- Grupo de Investigaciones Microbiológicas, Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Bogotá, Colombia
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Gaspe MS, Provecho YM, Piccinali RV, Gürtler RE. Where do these bugs come from? Phenotypic structure of Triatoma infestans populations after control interventions in the Argentine Chaco. Mem Inst Oswaldo Cruz 2015; 110:310-8. [PMID: 25946158 PMCID: PMC4489468 DOI: 10.1590/0074-02760140376] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 03/18/2015] [Indexed: 11/22/2022] Open
Abstract
House re-invasion by native triatomines after insecticide-based control campaigns
represents a major threat for Chagas disease vector control. We conducted a
longitudinal intervention study in a rural section (Area III, 407 houses) of Pampa
del Indio, northeastern Argentina, and used wing geometric morphometry to compare
pre-spray and post-spray (re-infestant bugs) Triatoma infestans
populations. The community-wide spraying with pyrethroids reduced the prevalence of
house infestation by T. infestans from 31.9% to < 1% during a
four-year follow-up, unlike our previous studies in the neighbouring Area I. Two
groups of bug collection sites differing in wing shape variables before interventions
(including 221 adults from 11 domiciles) were used as a reference for assigning 44
post-spray adults. Wing shape variables from post-spray, high-density bug colonies
and pre-spray groups were significantly different, suggesting that re-infestant
insects had an external origin. Insects from one house differed strongly in wing
shape variables from all other specimens. A further comparison between insects from
both areas supported the existence of independent re-infestation processes within the
same district. These results point to local heterogeneities in house re-infestation
dynamics and emphasise the need to expand the geographic coverage of vector
surveillance and control operations to the affected region.
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Affiliation(s)
- María Sol Gaspe
- Instituto de Ecología, Genética y Evolución, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Yael Mariana Provecho
- Instituto de Ecología, Genética y Evolución, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Romina Valeria Piccinali
- Instituto de Ecología, Genética y Evolución, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ricardo Esteban Gürtler
- Instituto de Ecología, Genética y Evolución, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Buenos Aires, Argentina
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Macchiaverna NP, Gaspe MS, Enriquez GF, Tomassone L, Gürtler RE, Cardinal MV. Trypanosoma cruzi infection in Triatoma sordida before and after community-wide residual insecticide spraying in the Argentinean Chaco. Acta Trop 2015; 143:97-102. [PMID: 25579426 DOI: 10.1016/j.actatropica.2014.12.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 12/15/2014] [Accepted: 12/19/2014] [Indexed: 10/24/2022]
Abstract
Triatoma sordida is a secondary vector of Trypanosoma cruzi in the Gran Chaco and Cerrado eco-regions where it frequently infests peridomestic and domestic habitats. In a well-defined area of the humid Argentine Chaco, very few T. sordida were found infected when examined by optical microscopic examination (OM). In order to further assess the role of T. sordida and the relative magnitude of subpatent bug infections, we examined the insects for T. cruzi infection, parasite Discrete Typing Units (DTUs) and bloodmeal sources using various molecular techniques. Among 205 bugs with a negative or no OM-based diagnosis, the prevalence of infection determined by kDNA-PCR was nearly the same in bugs captured before (6.3%) and 4 months after insecticide spraying (6.4%). On average, these estimates were sixfold higher than the prevalence of infection based on OM (1.1%). Only TcI was identified, a DTU typically associated with opossums and rodents. Chickens and turkeys were the only bloodmeal sources identified in the infected specimens and the main local hosts at the bugs' capture sites. As birds are refractory to T. cruzi infection, further studies are needed to identify the infectious bloodmeal hosts. The persistent finding of infected T. sordida after community-wide insecticide spraying highlights the need of sustained vector surveillance to effectively prevent T. cruzi transmission in the domestic and peridomestic habitats.
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Microcavia australis (Caviidae, Rodentia), a new highly competent host of Trypanosoma cruzi I in rural communities of northwestern Argentina. Acta Trop 2015; 142:34-40. [PMID: 25447830 DOI: 10.1016/j.actatropica.2014.10.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 10/15/2014] [Accepted: 10/26/2014] [Indexed: 12/11/2022]
Abstract
Rodents are well-known hosts of Trypanosoma cruzi but little is known on the role of some caviomorph rodents. We assessed the occurrence and prevalence of T. cruzi infection in Microcavia australis ("southern mountain, desert or small cavy") and its infectiousness to the vector Triatoma infestans in four rural communities of Tafí del Valle department, northwestern Argentina. Parasite detection was performed by xenodiagnosis and polymerase chain reaction amplification of the hyper-variable region of kinetoplast DNA minicircles of T. cruzi (kDNA-PCR) from blood samples. A total of 51 cavies was captured in traps set up along cavy paths in peridomestic dry-shrub fences located between 25 and 85 m from the nearest domicile. We document the first record of M. australis naturally infected by T. cruzi. Cavies presented a very high prevalence of infection (46.3%; 95% confidence interval, CI=33.0-59.6%). Only one (4%) of 23 cavies negative by xenodiagnosis was found infected by kDNA-PCR. TcI was the only discrete typing unit identified in 12 cavies with a positive xenodiagnosis. The infectiousness to T. infestans of cavies positive by xenodiagnosis or kDNA-PCR was very high (mean, 55.8%; CI=48.4-63.1%) and exceeded 80% in 44% of the hosts. Cavies are highly-competent hosts of T. cruzi in peridomestic habitats near human dwellings in rural communities of Tucumán province in northwestern Argentina.
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Santo-Orihuela PL, Carvajal G, Picollo MI, Vassena CV. Analysing deltamethrin susceptibility and pyrethroid esterase activity variations in sylvatic and domestic Triatoma infestans at the embryonic stage. Mem Inst Oswaldo Cruz 2015; 108:1031-6. [PMID: 24402155 PMCID: PMC4005558 DOI: 10.1590/0074-0276130184] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 09/26/2013] [Indexed: 11/22/2022] Open
Abstract
The aim of the present work was to study the deltamethrin susceptibility of eggs from Triatoma infestans populations and the contribution of pyrethroid esterases to deltamethrin degradation. Insects were collected from sylvatic areas, including Veinte de Octubre and Kirus-Mayu (Bolivia) and from domiciliary areas, including El Palmar (Bolivia) and La Pista (Argentina). Deltamethrin susceptibility was determined by dose-response bioassays. Serial dilutions of deltamethrin (0.0005-1 mg/mL) were topically applied to 12-day-old eggs. Samples from El Palmar had the highest lethal dose ratio (LDR) value (44.90) compared to the susceptible reference strain (NFS), whereas the Veinte de Octubre samples had the lowest value (0.50). Pyrethroid esterases were evaluated using 7-coumaryl permethrate (7-CP) on individually homogenised eggs from each population and from NFS. The El Palmar and La Pista samples contained 40.11 and 36.64 pmol/min/mg protein, respectively, and these values were statistically similar to NFS (34.92 pmol/min/mg protein) and different from Kirus-Mayu and Veinte de Octubre (27.49 and 22.69 pmol/min/mg protein, respectively). The toxicological data indicate that the domestic populations were resistant to deltamethrin, but no statistical contribution of 7-CP esterases was observed. The sylvatic populations had similar LDR values to NFS, but lower 7-CP esterase activities. Moreover, this is the first study of the pyrethroid esterases on T. infestans eggs employing a specific substrate (7-CP).
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Provecho YM, Gaspe MS, del Pilar Fernández M, Enriquez GF, Weinberg D, Gürtler RE. The peri-urban interface and house infestation with Triatoma infestans in the Argentine Chaco: an underreported process? Mem Inst Oswaldo Cruz 2014; 109:923-34. [PMID: 25410997 PMCID: PMC4296498 DOI: 10.1590/0074-0276140225] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 09/10/2014] [Indexed: 02/08/2023] Open
Abstract
Peri-urban infestations with triatomine bugs, their sources and their dynamics have
rarely been investigated. Here, we corroborated the reported occurrence of
Triatoma infestans in a peri-urban area and in neighbouring rural
houses in Pampa del Indio, in the Argentine Chaco, and identified its putative
sources using spatial analysis and demographic questionnaires. Peri-urban
householders reported that 10% of their premises had triatomines, whereas T.
infestans was collected by timed manual searches or community-based
surveillance in only nine (3%) houses. Trypanosoma cruzi-infected
T. infestans and Triatoma sordida were collected
indoors only in peri-urban houses and were infected with TcV
and TcI, respectively. The triatomines fed on chickens,
cats and humans. Peri-urban infestations were most frequent in a squatter settlement
and particularly within the recently built mud houses of rural immigrants, with
large-sized households, more dogs and cats and more crowding. Several of the observed
infestations were most likely associated with passive bug transport from other
sources and with active bug dispersal from neighbouring foci. Thus, the households in
the squatter settlement were at a greater risk of bug invasion and colonisation. In
sum, the incipient process of domestic colonisation and transmission, along with
persistent rural-to-urban migratory flows and unplanned urbanisation, indicate the
need for active vector surveillance and control actions at the peri-urban interface
of the Gran Chaco.
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Affiliation(s)
- Yael M Provecho
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, National Council of Scientific and Technological Research, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - M Sol Gaspe
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, National Council of Scientific and Technological Research, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - M del Pilar Fernández
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, National Council of Scientific and Technological Research, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gustavo F Enriquez
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, National Council of Scientific and Technological Research, Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | - Ricardo E Gürtler
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, National Council of Scientific and Technological Research, Universidad de Buenos Aires, Buenos Aires, Argentina
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Effects of anthropogenic and demographic factors on patterns of parasitism in African small mammal communities. Parasitology 2014; 142:512-22. [PMID: 25262668 DOI: 10.1017/s0031182014001450] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Habitat disturbance often results in alterations in community structure of small mammals. Additionally, the parasites harboured by these small mammals may be impacted by environmental changes or indirectly affected by changes in available hosts. To improve our understanding of this interplay, we examined the patterns of parasitism in small mammal communities from a variety of habitats in forested Uganda. Small mammals were collected from areas experiencing variable habitat disturbance, host density and species richness. The analysis focused on 3 most abundant rodent species, Lophuromys aquilus, Praomys jacksoni and Hylomyscus stella, and a diverse group of parasites they harbour. The impact of various habitat and host community factors on parasite prevalence was examined using linear regression and Spearman's rank-order correlation. We further investigated the parasite communities associated with each individual using correspondence analysis. We determined that, parasite prevalence and richness may be occasionally influenced by community and habitat factors, but taxonomy is a driving force in influencing the parasite community harboured by an individual host. Ultimately, applying general principles across a broad range of disturbance levels and diverse host communities needs to be approached with caution in complex communities.
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Cardinal MV, Orozco MM, Enriquez GF, Ceballos LA, Gaspe MS, Alvarado-Otegui JA, Gurevitz JM, Kitron U, Gürtler RE. Heterogeneities in the ecoepidemiology of Trypanosoma cruzi infection in rural communities of the Argentinean Chaco. Am J Trop Med Hyg 2014; 90:1063-73. [PMID: 24732461 DOI: 10.4269/ajtmh.13-0251] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
We conducted a cross-sectional survey of Trypanosoma cruzi infection of Triatoma infestans as well as dogs and cats in 327 households from a well-defined rural area in northeastern Argentina to test whether the household distribution of infection differed between local ethnic groups (Tobas and Creoles) and identify risk factors for host infection. Overall prevalence of infection of bugs (27.2%; 95% confidence interval = 25.3-29.3%), dogs (26.0%; 95% confidence interval = 23.3-30.1%), and cats examined (28.7%; 95% confidence interval = 20.2-39.0%) was similar. A multimodel inference approach showed that infection in dogs was associated strongly with the intensity and duration of local exposure to infected bugs and moderately with household ethnic background. Overall, Toba households were at a substantially greater risk of infection than Creole households. The strong heterogeneities in the distribution of bug, dog, and cat infections at household, village, and ethnic group levels may be used for targeted vector and disease control.
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Affiliation(s)
- M Victoria Cardinal
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina; Department of Environmental Studies, Emory University, Atlanta, Georgia
| | - M Marcela Orozco
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina; Department of Environmental Studies, Emory University, Atlanta, Georgia
| | - Gustavo F Enriquez
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina; Department of Environmental Studies, Emory University, Atlanta, Georgia
| | - Leonardo A Ceballos
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina; Department of Environmental Studies, Emory University, Atlanta, Georgia
| | - María Sol Gaspe
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina; Department of Environmental Studies, Emory University, Atlanta, Georgia
| | - Julián A Alvarado-Otegui
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina; Department of Environmental Studies, Emory University, Atlanta, Georgia
| | - Juan M Gurevitz
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina; Department of Environmental Studies, Emory University, Atlanta, Georgia
| | - Uriel Kitron
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina; Department of Environmental Studies, Emory University, Atlanta, Georgia
| | - Ricardo E Gürtler
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina; Department of Environmental Studies, Emory University, Atlanta, Georgia
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Mejía-Jaramillo AM, Agudelo-Uribe LA, Dib JC, Ortiz S, Solari A, Triana-Chávez O. Genotyping of Trypanosoma cruzi in a hyper-endemic area of Colombia reveals an overlap among domestic and sylvatic cycles of Chagas disease. Parasit Vectors 2014; 7:108. [PMID: 24656115 PMCID: PMC3994407 DOI: 10.1186/1756-3305-7-108] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 03/04/2014] [Indexed: 11/30/2022] Open
Abstract
Background Chagas disease is a neglected illness caused by the Trypanosoma cruzi parasite, which widely affects American communities. This study attempted to identify T. cruzi genotypes circulating in four indigenous communities of the Sierra Nevada of Santa Marta, Colombia, to investigate parasite transmission dynamics in these communities. In addition, some epidemiological variables to determine the risk factors for infection with this parasite, such as the prevalence of T. cruzi infection, the triatomine species, and the domestic and sylvatic mammals that act as vectors and reservoirs of the parasite in the domestic, peridomestic and sylvatic cycles, were examined. Methods We developed a prospective study to identify the main risk factors associated with T. cruzi infection in the region. The T. cruzi prevalence was determined by ELISA, IFA and PCR. Triatomines species and both domestic and sylvatic mammals from all communities were captured and sampled. To analyze parasite transmission dynamics in these four communities, eight DNA parasite probes were generated from insect and reservoir samples, and a DNA blot analysis were carried out. Results Serological studies revealed 37% prevalence in the four communities, and Kasakumake was the most endemic region, containing approximately 70% seropositives. Moreover, the molecular diagnosis showed a high correlation between the serological data and the T. cruzi circulating in the patients’ blood. A total of 464 triatomine insects were collected in domestic, peridomestic and sylvatic environments, and these insects belonged to five different species; Rhodnius prolixus and Triatoma dimidiata were the two more important species transmitting the parasite. After studying the eco-epidemiological factors in these four communities, the most important risk factors for infection with the parasite were determined. These risk factors are a high infection rate of people and domestic animals, the construction materials of the houses, the presence of infected triatomines inside the human dwellings, the proximity between houses and a sylvatic environment with several triatomine species and wild animals. Finally, the molecular characterization of T. cruzi showed the presence of three haplotypes and complex T. cruzi mixed infections in all reservoirs. Conclusions Active transmission of T. cruzi is present in four indigenous communities of the Sierra Nevada de Santa Marta with overlap between the domestic and the sylvatic transmission cycles of Chagas disease.
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Affiliation(s)
| | | | | | | | | | - Omar Triana-Chávez
- Grupo BCEI, Universidad de Antioquia UdeA, Calle 70 No, 52-21 Medellin, Colombia.
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Orozco MM, Piccinali RV, Mora MS, Enriquez GF, Cardinal MV, Gürtler RE. The role of sigmodontine rodents as sylvatic hosts of Trypanosoma cruzi in the Argentinean Chaco. INFECTION GENETICS AND EVOLUTION 2014; 22:12-22. [PMID: 24394448 DOI: 10.1016/j.meegid.2013.12.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 12/18/2013] [Accepted: 12/21/2013] [Indexed: 11/28/2022]
Abstract
The role of rodents in the sylvatic transmission of Trypanosoma cruzi has seldom been investigated using parasitological and molecular methods. We assessed the occurrence of T. cruzi in wild small rodents from Pampa del Indio, in the Argentinean Chaco, and identified the taxonomic status of positive rodents by sequencing a fragment of cytochrome b gene (cytb) and performing BLAST searches and phylogenetic analyses. A total of 176 Sigmodontinae rodents was captured in six surveys using 5425 trap-nights in a wide range of sylvatic habitats between 2009 and 2011. Host infection was determined by xenodiagnosis and by polymerase chain reaction amplification of the hyper-variable region of kinetoplast DNA minicircles of T. cruzi (kDNA-PCR) from blood samples. None of the 176 rodents examined was xenodiagnosis-positive. The prevalence of infection determined by kDNA-PCR from blood samples was 16.2% (95% confidence interval, 10.1-21.9%). Half of the infections detected by kDNA-PCR were confirmed by nuclear satellite DNA-PCR or by kDNA-PCR of the rectal contents of xenodiagnostic bugs. The 24 positive specimens were assigned to eight species, providing the first records of T. cruzi in Akodon montensis, Akodon toba, Graomys chacoensis, and Oligoryzomys chacoensis. The occurrence of T. cruzi infection in Oligoryzomys nigripes, Calomys callosus, Necromys lasiurus and Oecomys sp. (most probably Oecomys mamorae) from the Gran Chaco is also reported for the first time. Although sigmodontine rodents were frequently infected, the intensity of bug rectal infection with T. cruzi was below the detection limit of xenodiagnosis (subpatent infectiousness to bugs), indicating they had a low reservoir host competence.
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Affiliation(s)
- M Marcela Orozco
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; Instituto de Ecología, Genética y Evolución (IEGEBA), CONICET, Argentina
| | - Romina V Piccinali
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; Instituto de Ecología, Genética y Evolución (IEGEBA), CONICET, Argentina
| | - Matías S Mora
- Instituto de Investigaciones Marinas y Costeras (IIMyC, CONICET), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, 7600, Mar del Plata, Argentina
| | - Gustavo F Enriquez
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; Instituto de Ecología, Genética y Evolución (IEGEBA), CONICET, Argentina
| | - M Victoria Cardinal
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; Instituto de Ecología, Genética y Evolución (IEGEBA), CONICET, Argentina
| | - Ricardo E Gürtler
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; Instituto de Ecología, Genética y Evolución (IEGEBA), CONICET, Argentina.
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Retrospective molecular integrated epidemiology of Chagas disease in Colombia. INFECTION GENETICS AND EVOLUTION 2013; 20:148-54. [DOI: 10.1016/j.meegid.2013.08.028] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 08/27/2013] [Accepted: 08/28/2013] [Indexed: 11/17/2022]
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Carbajal-de-la-Fuente AL, Yadón ZE. A scientometric evaluation of the Chagas disease implementation research programme of the PAHO and TDR. PLoS Negl Trop Dis 2013; 7:e2445. [PMID: 24244761 PMCID: PMC3820726 DOI: 10.1371/journal.pntd.0002445] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The Special Programme for Research and Training in Tropical Diseases (TDR) is an independent global programme of scientific collaboration cosponsored by the United Nations Children's Fund, the United Nations Development Program, the World Bank, and the World Health Organization. TDR's strategy is based on stewardship for research on infectious diseases of poverty, empowerment of endemic countries, research on neglected priority needs, and the promotion of scientific collaboration influencing global efforts to combat major tropical diseases. In 2001, in view of the achievements obtained in the reduction of transmission of Chagas disease through the Southern Cone Initiative and the improvement in Chagas disease control activities in some countries of the Andean and the Central American Initiatives, TDR transferred the Chagas Disease Implementation Research Programme (CIRP) to the Communicable Diseases Unit of the Pan American Health Organization (CD/PAHO). This paper presents a scientometric evaluation of the 73 projects from 18 Latin American and European countries that were granted by CIRP/PAHO/TDR between 1997 and 2007. We analyzed all final reports of the funded projects and scientific publications, technical reports, and human resource training activities derived from them. Results about the number of projects funded, countries and institutions involved, gender analysis, number of published papers in indexed scientific journals, main topics funded, patents inscribed, and triatomine species studied are presented and discussed. The results indicate that CIRP/PAHO/TDR initiative has contributed significantly, over the 1997–2007 period, to Chagas disease knowledge as well as to the individual and institutional-building capacity.
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Affiliation(s)
- Ana Laura Carbajal-de-la-Fuente
- Leishmaniasis Transmitters Laboratory, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, (IEGEBA-CONICET) University of Buenos Aires, Buenos Aires, Argentina
| | - Zaida E. Yadón
- Communicable Diseases Unit, Health Surveillance, Disease Prevention and Control, Pan American Health Organization, Washington, D.C., United States of America
- * E-mail:
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Sartor PA, Ceballos LA, Orozco MM, Cardinal MV, Gürtler RE, Leguizamón MS. Trans-sialidase inhibition assay detects Trypanosoma cruzi infection in different wild mammal species. Vector Borne Zoonotic Dis 2013; 13:581-5. [PMID: 23930975 DOI: 10.1089/vbz.2012.1125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The detection of Trypanosoma cruzi infection in mammals is crucial for understanding the eco-epidemiological role of the different species involved in parasite transmission cycles. Xenodiagnosis (XD) and hemoculture (HC) are routinely used to detect T. cruzi in wild mammals. Serological methods are much more limited because they require the use of specific antibodies to immunoglobulins of each mammalian species susceptible to T. cruzi. In this study we detected T. cruzi infection by trans-sialidase (TS) inhibition assay (TIA). TIA is based on the antibody neutralization of a recombinant TS that avoids the use of anti-immunoglobulins. TS activity is not detected in the co-endemic protozoan parasites Leishmania spp and T. rangeli. In the current study, serum samples from 158 individuals of nine wild mammalian species, previously tested by XD, were evaluated by TIA. They were collected from two endemic areas in northern Argentina. The overall TIA versus XD co-reactivity was 98.7% (156/158). All 18 samples from XD-positive mammals were TIA-positive (co-positivity, 100%) and co-negativity was 98.5% (138/140). Two XD-negative samples from a marsupial (Didelphis albiventris) and an edentate (Dasypus novemcinctus) were detected by TIA. TIA could be used as a novel tool for serological detection of Trypanosoma cruzi in a wide variety of sylvatic reservoir hosts.
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Affiliation(s)
- Paula A Sartor
- Instituto de Microbiología y Parasitología Médica, Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Tecnológicas, Argentina
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Gurevitz JM, Gaspe MS, Enriquez GF, Provecho YM, Kitron U, Gürtler RE. Intensified surveillance and insecticide-based control of the Chagas disease vector Triatoma infestans in the Argentinean Chaco. PLoS Negl Trop Dis 2013; 7:e2158. [PMID: 23593525 PMCID: PMC3623707 DOI: 10.1371/journal.pntd.0002158] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 02/27/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The elimination of Triatoma infestans, the main Chagas disease vector in the Gran Chaco region, remains elusive. We implemented an intensified control strategy based on full-coverage pyrethroid spraying, followed by frequent vector surveillance and immediate selective insecticide treatment of detected foci in a well-defined rural area in northeastern Argentina with moderate pyrethroid resistance. We assessed long-term impacts, and identified factors and procedures affecting spray effectiveness. METHODS AND FINDINGS After initial control interventions, timed-manual searches were performed by skilled personnel in 4,053 sites of 353-411 houses inspected every 4-7 months over a 35-month period. Residual insecticide spraying was less effective than expected throughout the three-year period, mainly because of the occurrence of moderate pyrethroid resistance and the limited effectiveness of selective treatment of infested sites only. After initial interventions, peridomestic infestation prevalence always exceeded domestic infestation, and timed-manual searches consistently outperformed householders' bug detection, except in domiciles. Most of the infestations occurred in houses infested at baseline, and were restricted to four main ecotopes. Houses with an early persistent infestation were spatially aggregated up to a distance of 2.5 km. An Akaike-based multi-model inference approach showed that new site-level infestations increased substantially with the local availability of appropriate refugia for triatomine bugs, and with proximity to the nearest site found infested at one or two preceding surveys. CONCLUSIONS AND SIGNIFICANCE Current vector control procedures have limited effectiveness in the Gran Chaco. Selective insecticide sprays must include all sites within the infested house compound. The suppression of T. infestans in rural areas with moderate pyrethroid resistance requires increased efforts and appropriate management actions. In addition to careful, systematic insecticide applications, housing improvement and development policies that improve material conditions of rural villagers and reduce habitat suitability for bugs will contribute substantially to sustainable vector and disease control in the Gran Chaco.
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Affiliation(s)
- Juan M. Gurevitz
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María Sol Gaspe
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gustavo F. Enriquez
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Yael M. Provecho
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Uriel Kitron
- Department of Environmental Studies, Emory University, Atlanta, Georgia, United States of America
| | - Ricardo E. Gürtler
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina
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Gaspe MS, Gurevitz JM, Gürtler RE, Dujardin JP. Origins of house reinfestation with Triatoma infestans after insecticide spraying in the Argentine Chaco using wing geometric morphometry. INFECTION GENETICS AND EVOLUTION 2013; 17:93-100. [PMID: 23557838 DOI: 10.1016/j.meegid.2013.03.044] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 03/01/2013] [Accepted: 03/25/2013] [Indexed: 10/27/2022]
Abstract
Identifying the origins of insect vectors collected after community-wide residual insecticide applications is a relevant challenge in the Gran Chaco region where the main vector of Chagas disease Triatoma infestans usually reinfests human dwellings. Wing geometric morphometry was used to compare the right wings of 63 males and 54 females collected at 4 months post-spraying (MPS) with those from 165 males and 111 females collected before full-coverage spraying with pyrethroids in a well-defined rural area in Northeastern Argentina. Male and female wing centroid size resulted significantly larger at 4MPS than before interventions, but no significant changes in shape were detected. Metric disparity (variance of shape) varied significantly in males but not in females. Using shape variables, a relatively large fraction of post-spraying males (70%) and females (54%) could not be differentiated from those collected at the same source house or at the nearest infested house before interventions. Bugs collected at 4 and 8MPS in a persistently infested house were mainly assigned to the source house. These results support the hypothesis of persistent bug populations that survived the insecticide application at local spatial scales, and are consistent with the occurrence of vector control failures most likely related to moderate pyrethroid resistance. Wing geometric morphometry is a useful tool for identifying sources of reinfestation, but it is limited by the spatial structure found in the reference populations. Combined with field and genetic data, this approach may contribute to the understanding of the reinfestation process and improvement of vector control strategies.
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Affiliation(s)
- M Sol Gaspe
- Laboratorio de Eco-Epidemiología, Depto. de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires-IEGEBA, CONICET-UBA, Ciudad Universitaria, 1428EHA Buenos Aires, Argentina
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Orozco MM, Enriquez GF, Alvarado-Otegui JA, Cardinal MV, Schijman AG, Kitron U, Gürtler RE. New sylvatic hosts of Trypanosoma cruzi and their reservoir competence in the humid Chaco of Argentina: a longitudinal study. Am J Trop Med Hyg 2013; 88:872-82. [PMID: 23530075 DOI: 10.4269/ajtmh.12-0519] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A four-year longitudinal study of the structure of sylvatic transmission cycles of Trypanosoma cruzi, reservoir host competence and parasite discrete typing units was conducted in a disturbed rural area of the humid Chaco in Argentina. Among 190 mammals examined by xenodiagnosis and polymerase chain reaction amplification, the composite prevalence of infection was substantially higher in Dasypus novemcinctus armadillos (57.7%) and Didelphis albiventris opossums (38.1%) than in Euphractus sexcinctus (20.0%), Tolypeutes matacus (12.5%), and Chaetophractus vellerosus (6.3%) armadillos. Trypanosoma cruzi was detected for the first time in Thylamys pusilla small opossums and in two unidentified small rodents. Infection was spatially aggregated only in armadillos. All Didelphis were infected with T. cruzi I and all armadillo species were infected with T. cruzi III, implying two distinct sylvatic cycles with no inputs from the domestic cycle. Dasypus armadillos and Didelphis opossums were much more infectious to vectors than other armadillos, small opossums, or rodents.
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Affiliation(s)
- M Marcela Orozco
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina
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Enriquez GF, Cardinal MV, Orozco MM, Lanati L, Schijman AG, Gürtler RE. Discrete typing units of Trypanosoma cruzi identified in rural dogs and cats in the humid Argentinean Chaco. Parasitology 2013; 140:303-8. [PMID: 23058180 PMCID: PMC3721149 DOI: 10.1017/s003118201200159x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The discrete typing units (DTUs) of Trypanosoma cruzi that infect domestic dogs and cats have rarely been studied. With this purpose we conducted a cross-sectional xenodiagnostic survey of dog and cat populations residing in 2 infested rural villages in Pampa del Indio, in the humid Argentine Chaco. Parasites were isolated by culture from 44 dogs and 12 cats with a positive xenodiagnosis. DTUs were identified from parasite culture samples using a strategy based on multiple polymerase-chain reactions. TcVI was identified in 37 of 44 dogs and in 10 of 12 cats, whereas TcV was identified in 5 dogs and in 2 cats -a new finding for cats. No mixed infections were detected. The occurrence of 2 dogs infected with TcIII -classically found in armadillos- suggests a probable link with the local sylvatic transmission cycle involving Dasypus novemcinctus armadillos and a potential risk of human infection with TcIII. Our study reinforces the importance of dogs and cats as domestic reservoir hosts and sources of various DTUs infecting humans, and suggests a link between dogs and the sylvatic transmission cycle of TcIII.
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Affiliation(s)
- G F Enriquez
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires, Buenos Aires, Argentina
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