Rev Costarr Salud Pública 2011; 20: 97-101 N.° 2– Vol. 20 – Julio-Diciembre 2011 Original Breve Persistence of Chagas Persistencia de la disease active enfermedad de Chagas transmission among y trasmisión activa entre dogs in Venezuela rural perros en una comunidad community rural de Venezuela Claudina del Carmen Rodríguez-Bonfante1, María Elena Rojas2, Elis Aldana3, Juan Luis Concepción4, Rafael Armando Bonfante-Cabarcas5 1 MD MSc Medicina Tropical, Unidad de Investigaciones en Parasitología Médica, UCLA, [email protected] 2 MD, Medicina Integral del Medio Urbano, Universidad Centro-Occidental “Lisandro Alvarado” (UCLA), Barquisimeto, Estado Lara, [email protected]; 3 PhD Biology, Laboratorio de Entomología “Herman Lent”, Facultad de Ciencias, Universidad de Los Andes (ULA), Mérida, Estado Mérida, [email protected]; 4 PhD Fundamental Medicine, Laboratorio de Enzimología de Parásitos, CIGEN, ULA, [email protected]; 5MD PhD Science, Unidad de Bioquímica, UCLA, [email protected]. Received 25 noviembre 2011 Accepted 15 december 2011 ABSTRACT RESUMEN Objective: To determine human and canine seroprevalence, Objetivo: Determinar la seroprevalencia humana y canina del entomologic indexes and risk factors for Chagas’ disease índice entomológico y factores de riesgo para la transmisión transmission in a rural community. de la enfermedad de Chagas en una comunidad rural. Method: 48 houses, 162 people, and 55 canines were Materiales y Método: Se incluyeron 48 casas, 162 personas, sampled. Serum anti-Trypanosoma cruzi antibodies were y se tomaron muestras de 55 caninos. se determinaron determined by means of ELISA and MABA techniques anticuerpos séricos anti-Trypanosoma cruzi mediante técnicas using recombinant antigens. Triatomine collection were de ELISA y MABA, utilizando antígenos recombinantes. La carried out by passive search by community and an active/ recolección de triatominos se llevó a cabo mediante búsqueda systematic house, T. cruzi infection was determined by pasiva sistemática en la comunidad y casas. La infección por direct microcopy. T. cruzi se determinó mediante microscopia directa. Results: 2,47% of the humans and 18.18% of the canines Resultados: El 2,47 % de los humanos y 18,18 % de los were positive to serum anti-T.cruzi antibodies. The triatomine caninos fueron positivos al suero anti-T.cruzi. Los triatominos bugs found was 98.24% and 1.76% Eratyrus mucronatus. encontrados fueron T. maculata (98,24 %) y Eratyrus Vector’s indexes were: 0 % vector infection, 18.75% indoor mucronatus (1,76%). No hubo infección vectorial, el 18,75 house infestation, 25% outdoor house infestation, 0% indoor % de infestación intradomiciliaria, 25 % de infestación house colonization, 83.33 % outdoor house colonization and extradomiciliaria, no hubo colonización intradomiciliar, el 4.16% house co-infestation. We obtained an association 83,33 % de colonización extradomiciliar y el 4,16 % de between house triatomine infestation and visualization of infestación intradomiciliar. Se obtuvo una asociación entre wild animals in the house. infestación intradomiciliar por triatominos y la visualización de Discussion: there are not vector transmission of Chagas los animales en la casa. disease in the community, however, high dog’s prevalence Discusión: No se observo transmisión vectorial de la is related to their biological habits and behavior. enfermedad de Chagas en la comunidad, sin embargo, la Key words: Chagas disease, Trypanosomiasis, alta prevalencia en perros está relacionada con sus hábitos Seroepidemiologic Studies, Dog disease, Venezuela. biológicos y el comportamiento. (source: MeSh, NLM) Palabras clave: Enfermedad de Chagas, Tripanosomiasis, Estudios seroepidemiológicos, Canis familiaris, Venezuela. (fuente: DeCS, BIREME) REVISTA COSTARRICENSE DE SALUD PUBLICA © ACOSAP. Asociación Costarricense de Salud Pública Rev Costarr Salud Pública 2011, Vol. 20, N.° 2 Revista Fundada en 1992 97 ISSN versión impresa: 1409-1429 COMITÉ EDITORIAL Editor Amada Aparicio Llanos Co-Editor Azalea Espinoza Aguirre Editores asociados Ricardo Morales Vargas Ministerio de Salud, Costa Rica Henry Wasserman Teitelbaum Ministerio de Salud, Costa Rica Jeffrey E. Harris Massachusetts Institute of Technology, EUA María E. Villalobos Hernández Ministerio de Salud, Costa Rica María D. Fiuza Pérez Sociedad Canaria de Salud Pública, España Comité Administrativo Omar Arce Cedeño Comité Consultivo 2009-2010 Germán Cedeño Volkmar Universidad de Costa Rica Patricia Barber Pérez Universidad de Las Palmas de Gran Canaria, España Olga Segura Cárdenas Ministerio de Salud, Costa Rica María Carmen Oconitrillo Gamboa Ministerio de Salud, Costa Rica Isabel Sing Bennet Universidad Latina, Costa Rica Melvin Morera Salas Caja Costarricense del Seguro Social Juan Rafael Vargas Universidad de Costa Rica Federico Paredes Valverde Ministerio de Salud, Costa Rica José Pablo Molina Velázquez Ministerio de Salud, Costa Rica Rev Costarr Salud Pública 2009, Vol. 18, N.° 1 I Rodríguez-Bonfante C, et al. n Venezuela, there has been a decline in prevalence MATERIALS AND METHODS rates for Chagas disease, from 44,5 % in the decade The study was conducted in the community of El Paso I1950 to 1960(1), to 9,2 % in the year 1990(2) and de Baragua, parish Xaguas, Urdaneta Municipality, 8,3 % in the year 2000(3). These results have been the Lara State, Venezuela, located at latitude N 10°36’40’’, result of replacement of dwellings by houses, vector longitude 70°22’12’’, 425 meters above sea level, elimination through residual insecticide spraying, with a seasonal continental climate with temperatures blood screening and prevention programs in endemic ranging between 27 °C and 39 °C, with xerosol soils, areas (2) and �ave led to a significant decrease in �t e 527,8 ml four years rainfall and thorn vegetation. rate of house’s infestation by Rhodnius prolixus (2), Human activities are agriculture and goat breeding. the principal vector in the transmission of Chagas’ Most common crops are melon, onion, sorghum, disease in Venezuela. As a consequence of this fact, paprika and aloe. secondary vectors are gradually occupying areas left Sampling unit was the house. Houses were selected by free by R. prolixus. stratified cl�ster on updated area ma�s. We ass�med Infestation and/or colonization of human houses 99 % confidence level 203 % ma�im�m error and a by Panstrongylus geniculatu s(4-6), Triatoma prevalence of Chagas’ disease assumed as 5 %. maculate (7) and Eratyrus mucronatus (7,8) has Sample was represented by 48 houses. Inclusion been documented in Venezuela. T. maculata is a wild criteria were the following: permanent residents of the species found naturally infected with T. cruzi, also it housing, no discrimination of sex or age and a voluntary has been frequently observed in the peridomicile (9), it written consent. We included canines that were docile is often found in coastal and xerophilous regions; it is enough to allow medical procedures. In total 162 considered primarily ornithophily, especially associated people were studied, 68 males and 94 females and with chickens and pigeons in the peridomicile (10). 55 dogs, 48 males and 7 females. Project and written Recently, our team working in a neighbor area observed consent was approved by Health Science School T. maculata as predominant vector, with ability to Ethics Committee at the Universidad Centrocidental infest (16,4 % infestation index) and colonize (39,1 “Lisandro Alvarado”. % colonization rate) human dwellings. The presence of T. maculata in the domicile and peridomicile was Serological diagnosis and entomological studies associated with the presence of hens, disorder in the Determination of serum anti-T.cruzi antibodies was surroundings, goats, poultry and/or domicile miss performed by ELISA and MABA and collection of distribution; achieving 1,57 % and 6,36 % of human’s triatomines was carried out through a passive search and dog’s seroprevalences, respectively (7). by inhabitants and by active and systematic review of Demonstration of active transmission requires the domicile and peridomicile by two members of the diagnosis of acute disease in the population and/or research team. Content of the insect’s distal intestine demonstration of seropositivity in infants, however, portion was diluted in saline 0,9 % and was studied by in most cases acute phase is unapparent and social optical microscopy in search of T. cruzi. For details see improvements that have occurred in communities Rojas et al, 2008 (7). at endemic areas has led to a effective protection Data are presented in absolute values, percentages or of children against vector contact. Therefore, numerical indexes. In order to evaluate relationships seroepidemiology studies in humans have limited between Chagas’ disease epidemiological risk factors significance to demonstrate active transmission. with house infestation or human seropositivity, we did By contrast, in endemic areas dogs are highly a binary logistic regression analysis, using version exposed to triatominos, because of their dynamic 11.0.1 SPSS �rogram. It �as acce�ted as significant behavior; sometimes sleep, hunt and feed on wild a p<0,05. animals infected meat, while it live in the house in a direct contact with humans. On the other hand, their RESULTS short life make it sentinels for Chagas’ disease active Of the 162 people surveyed, 4 individuals were found transmission (11, 12). Therefore, in the present paper to have anti-T.cruzi antibodies, representing a 2,47 % we conducted a seroepidemiologic