Periurban Trypanosoma cruzi–infected Triatoma infestans, Arequipa, Peru

Simple interventions may facilitate vector control and prevent periurban transmission of Chagas disease

Retracing Micro-Epidemics of Chagas Disease Using Epicenter Regression

Vector-borne transmission of Chagas disease has become an urban problem in the city of Arequipa, Peru, yet the debilitating symptoms that can occur in the chronic stage of the disease are rarely seen in hospitals in the city. The lack of obvious clinical disease in Arequipa has led to speculation that the local strain of the etiologic agent, Trypanosoma cruzi, has low chronic pathogenicity. The long asymptomatic period of Chagas disease leads us to an alternative hypothesis for the absence of clinical cases in Arequipa: transmission in the city may be so recent that most infected individuals have yet to progress to late stage disease. Here we describe a new method, epicenter regression, that allows us to infer the spatial and temporal history of disease transmission from a snapshot of a population's infection status. We show that in a community of Arequipa, transmission of T. cruzi by the insect vector Triatoma infestans occurred as a series of focal micro-epidemics, the oldest of which began only around 20 years ago. These micro-epidemics infected nearly 5% of the community before transmission of the parasite was disrupted through insecticide application in 2004. Most extant human infections in our study community arose over a brief period of time immediately prior to vector control. According to our findings, the symptoms of chronic Chagas disease are expected to be absent, even if the strain is pathogenic in the chronic phase of disease, given the long asymptomatic period of the disease and short history of intense transmission. Traducción al español disponible en Alternative Language Text S1/A Spanish translation of this article is available in Alternative Language Text S

Retracing Micro-Epidemics of Chagas Disease Using Epicenter Regression

Vector-borne transmission of Chagas disease has become an urban problem in the city of Arequipa, Peru, yet the debilitating symptoms that can occur in the chronic stage of the disease are rarely seen in hospitals in the city. The lack of obvious clinical disease in Arequipa has led to speculation that the local strain of the etiologic agent, Trypanosoma cruzi, has low chronic pathogenicity. The long asymptomatic period of Chagas disease leads us to an alternative hypothesis for the absence of clinical cases in Arequipa: transmission in the city may be so recent that most infected individuals have yet to progress to late stage disease. Here we describe a new method, epicenter regression, that allows us to infer the spatial and temporal history of disease transmission from a snapshot of a population\u27s infection status. We show that in a community of Arequipa, transmission of T. cruzi by the insect vector Triatoma infestans occurred as a series of focal micro-epidemics, the oldest of which began only around 20 years ago. These micro-epidemics infected nearly 5% of the community before transmission of the parasite was disrupted through insecticide application in 2004. Most extant human infections in our study community arose over a brief period of time immediately prior to vector control. According to our findings, the symptoms of chronic Chagas disease are expected to be absent, even if the strain is pathogenic in the chronic phase of disease, given the long asymptomatic period of the disease and short history of intense transmission

Targeted screening strategies to detect Trypanosoma cruzi infection in children.

Millions of people are infected with Trypanosoma cruzi, the causative agent of Chagas disease in Latin America. Anti-trypanosomal drug therapy can cure infected individuals, but treatment efficacy is highest early in infection. Vector control campaigns disrupt transmission of T. cruzi, but without timely diagnosis, children infected prior to vector control often miss the window of opportunity for effective chemotherapy.We performed a serological survey in children 2-18 years old living in a peri-urban community of Arequipa, Peru, and linked the results to entomologic, spatial and census data gathered during a vector control campaign. 23 of 433 (5.3% [95% CI 3.4-7.9]) children were confirmed seropositive for T. cruzi infection by two methods. Spatial analysis revealed that households with infected children were very tightly clustered within looser clusters of households with parasite-infected vectors. Bayesian hierarchical mixed models, which controlled for clustering of infection, showed that a child's risk of being seropositive increased by 20% per year of age and 4% per vector captured within the child's house. Receiver operator characteristic (ROC) plots of best-fit models suggest that more than 83% of infected children could be identified while testing only 22% of eligible children.We found evidence of spatially-focal vector-borne T. cruzi transmission in peri-urban Arequipa. Ongoing vector control campaigns, in addition to preventing further parasite transmission, facilitate the collection of data essential to identifying children at high risk of T. cruzi infection. Targeted screening strategies could make integration of diagnosis and treatment of children into Chagas disease control programs feasible in lower-resource settings

Exploration for Triatoma virus (TrV) infection in laboratory-reared triatomines of Latin America: a collaborative study

Triatoma virus (TrV) is a small, non-enveloped virus that has a +ssRNA genome and is currently classified under the Cripavirus genus of the Dicistroviridae family. TrV infects haematophagous triatomine insects (Hemiptera: Reduviidae), which are vectors of American Trypanosomiasis (Chagas disease). TrV can be transmitted through the horizontal fecal-oral route, and its infection causes either deleterious sublethal effects or even death of laboratory insect colonies. Various species of triatomines from different regions of Latin America are currently being reared in research laboratories, with little or no awareness of the presence of TrV; therefore, any biological conclusion drawn from experiments on insects infected with this virus is inherently affected by the side effects of its infection. In this study, we developed a mathematical model to estimate the sample size required for detecting a TrV infection. We applied this model to screen the infection in feces of triatomines belonging to insectaries from 13 Latin American countries, carrying out the identification of TrV by using reverse transcriptase PCR. TrV was detected in samples coming from Argentina, which is the country where several years ago the virus was first isolated from Triatoma infestans (Hemiptera: Reduviidae). Interestingly, several colonies from Brazil were also found infected with the virus. This positive result widens the TrV?s host range to a total of 14 triatomine species. Our findings suggest that many triatomine species distributed over a large region of South America may be naturally infected with TrV.Fil: Marti, Gerardo Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Estudios Parasitologicos y de Vectores. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Centro de Estudios Parasitologicos y de Vectores; ArgentinaFil: Echeverria, Maria Gabriela. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias. Departamento de Microbiología. Cátedra de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Susevich, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Estudios Parasitologicos y de Vectores. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Centro de Estudios Parasitologicos y de Vectores; ArgentinaFil: Ceccarelli, Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Estudios Parasitologicos y de Vectores. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Centro de Estudios Parasitologicos y de Vectores; ArgentinaFil: Balsalobre, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Estudios Parasitologicos y de Vectores. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Centro de Estudios Parasitologicos y de Vectores; ArgentinaFil: Canale, Delmi Margarita. Centro de Referencia de Vectores, Coordinación Nacional de Control de Vectores, Pabellón Rawson-Hospital Colonia; ArgentinaFil: Stariolo, Raúl Luis. Centro de Referencia de Vectores, Coordinación Nacional de Control de Vectores, Pabellón Rawson-Hospital Colonia; ArgentinaFil: Guérin, Diego M. A.. Universidad del País Vasco; España. Consejo Superior de Investigaciones Cientificas; España. Universidad Politécnica de Valencia; EspañaFil: González Cifuentes, Nadia L.. Universidad de Los Andes; ColombiaFil: Guhl, Felipe. Universidad de Los Andes; ColombiaFil: Bacigalupo, Antonella. Universidad de Chile; ChileFil: Cattan, Pedro E.. Universidad de Chile; ChileFil: Garcıa, Alejandro. Secretaria Regional Ministerial de Salud de Coquimbo; ChileFil: Villacis, Anita G.. Pontificia Universidad Catolica del Ecuador; EcuadorFil: Grijalva, Mario J.. Pontificia Universidad Catolica del Ecuador; Ecuador. Ohio University; Estados UnidosFil: Solorzano, Elizabeth. Universidad de San Carlos; GuatemalaFil: Monroy, Carlota. Universidad de San Carlos; GuatemalaFil: Espinoza Blanco, Yrma. Universidad Nacional Mayor de San Marcos; PerúFil: Cordova Benzaquen, Eleazar. Universidad Nacional San Agustín de Arequipa; PerúFil: Ruelas llerena, Nancy. Universidad Nacional San Agustín de Arequipa; PerúFil: Guzmán loayza, Miriam. Dirección Regional de Salud Moquegua; PerúFil: Caceres, Abraham G.. Universidad Nacional Mayor de San Marcos; PerúFil: Vences Blanco, Mauro O.. Universidad Nacional Autónoma de México; MéxicoFil: Salazar Schettino, Paz María. Universidad Nacional Autónoma de México; MéxicoFil: Martínez Martínez, Ignacio. Universidad Nacional Autónoma de México; MéxicoFil: Espinoza Gutiérrez, Bertha. Universidad Nacional Autónoma de México; MéxicoFil: Mojoli, Andrés. Centro para el Desarrollo de la Investigación Científica. Asunción; ParaguayFil: Rojas de Arias, Antonieta. Centro para el Desarrollo de la Investigación Científica. Asunción; ParaguayFil: Feliciangeli, M. Dora. Universidad de Carabobo Maracay; VenezuelaFil: Rivera Mendoza, Pedro. Fundación para el Desarrollo; NicaraguaFil: Rozas Dennis, Gabriela Susana. Universidad Nacional del Sur; ArgentinaFil: Sánchez Eugenia, Rubén. Unidad de Biofísica; EspañaFil: Aguirre, Jon. Unidad de Biofísica; España. Fundación Biofísica Bizkaia; EspañaFil: Viguera, Ana R.. Unidad de Biofísica; EspañaFil: Hernádez Suárez, Carlos M.. Universidad de Colima; México. Unidad Monterrey; MéxicoFil: Vilchez, Susana. Universidad de Granada; EspañaFil: Osuna, Antonio. Universidad de Granada; EspañaFil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de la Rioja. - Secretaria de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; ArgentinaFil: Mougabure Cueto, Gastón Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; ArgentinaFil: Esteban, Lidia. Universidad Industrial Santander; ColombiaFil: Angulo, Vıctor M.. Universidad Industrial Santander; ColombiaFil: Querido, Jailson F. B. Unidad de Biofísica; España. Fundación Biofísica Bizkaia; España. Universidad Nova de Lisboa; PortugalFil: Silva, Marcelo S.. Universidad Nova de Lisboa; PortugalFil: Marques, Tatiane. Universidade Federal do Triangulo Mineiro; BrasilFil: Anhe, Ana Carolina B. M.. Universidade Federal do Triangulo Mineiro; BrasilFil: Gomez Hernandez, Cesar. Universidade Federal do Triangulo Mineiro; BrasilFil: Ramirez, Luis E.. Universidade Federal do Triangulo Mineiro; BrasilFil: Rabinovich, Jorge Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Estudios Parasitologicos y de Vectores. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Centro de Estudios Parasitologicos y de Vectores; ArgentinaFil: Diotaiuti, Liléia. Centro de Pesquisas Rene Rachou-FIOCRUZ; BrasilFil: Guerin Aguilar , Diego Marcelo. Universidad del País Vasco; España. Unidad de Biofísica; España. Fundación Biofísica Bizkaia; Españ