Chagas Disease is a protozoan infection caused by Trypanosoma cruzi that has spread to vertebrates, including humans. This parasite is prevalent in the canine population (Canis familiaris) of the State of Yucatan, Mexico. Few studies have reported the serological frequency and factors associated with exposure to T. cruzi of dogs populations in rural communities of Yucatan. This study aims to estimate the frequency and factors associated with anti-T cruzi antibodies in dogs from a rural community in Yucatan. A research was carried out by convenience in 117 domestic dogs from the rural community. Blood samples from each dog to obtain serum were taken. The samples were analyzed by immunochromatography test for detecting anti-T. cruzi antibodies. A questionnaire to identify potential risk factors associated with seropositivity was administered to the owners of dogs. The response variables were analyzed by Chi square and variables with P <0.2 were analyzed using logistic regression. Serological frequency of 29.9% (95% CI: 21.61-38.21) was found. Factors associated with dogs with anti-T. cruzi were age (dogs> 1 year old, OR = 3.8 P = 0.02), place inhabited by the dog (dogs living outside the house, OR = 6.4 P = 0.04) and presence of Triatoma dimidiata bugs in houses (OR = 4.7 P = 0.006). We conclude that dogs of the community under study present T. cruzi antibodies (29.9% frequency) and three factors are associated with serologically positive dogs (adult dogs, dogs living outside the house and presence of bugs in the house).

La Enfermedad de Chagas es producida por el protozoario Trypanosoma cruzi que causa una infección ampliamente diseminada en vertebrados, incluido el hombre. Escasas investigaciones han reportado la frecuencia serológica y los factores asociados a la exposición de T. cruzi en las poblaciones caninas de comunidades rurales de Yucatán. El presente estudio tiene por objetivo estimar la frecuencia serológica e identificar factores asociados a anticuerpos anti-T cruzi en perros de una comunidad rural de Yucatán, México. Se realizó un estudio por conveniencia en 117 perros de la comunidad rural. Se tomaron muestras de sangre de cada perro para la obtención del suero. Las muestras fueron analizadas mediante una prueba de inmunocromatografía para detectar anticuerpos anti-T cruzi. A los propietarios de los perros se les aplicó un cuestionario para identificar posibles factores de riesgos asociados a la seropositividad. Las variables de respuesta fueron analizadas mediante Chi cuadrado y las variables con P < 0,2 fueron analizadas mediante regresión logística. Se encontró una frecuencia serológica del 29,9% (IC95%: 21,61-38,21). Los factores asociados a perros con anticuerpos anti-T cruzi fueron: edad (perros > 1 año de edad, OR= 3,8 P = 0,02), lugar donde habitan los perro (perros en el peridomicilio, OR= 6,4 P = 0,04) y presencia de triatominos en las casas (OR = 4,7 P = 0,006). Se concluye que los perros de la comunidad bajo estudio presentan anticuerpos anti-T. cruzi (29,9% de frecuencia) y tres factores se asocian a perros serológicamente positivos (perros adultos, perros que viven en el peridomicilio y presencia de triatominos en la casa).

Para determinar a infecção pelo Trypanosoma cruzi em mamíferos em Yucatan, México, foram estudados 372 animais selvagens e sinantrópicos incluindo carnívoros, marsupiais e roedores. Estudos sorológicos pela hemaglutinação indireta (IHA) foram realizados para detectar anticorpos contra o T. cruzi e estudos parasitológicos (esfregaços de sangue e histopatologia). De todos os animais testados 18,54% foram sorologicamente positivos com freqüência significativamente maior entre os silvestres (33,3%) em comparação com os sinantrópicos (11,79%). Para determinação do T. cruzi nos animais positivos, o sangue foi inoculado em camundongos brancos (tipo Webster) para provar a colonização miocárdica. Através da sua positividade sorológica e parasitológica, bem como seu comportamento no meio ambiente acompanhado pelas características sociais, econômicas e culturais da população, deduz-se que em Yucatan, México, Canis familiaris, Didelphis marsupialis e Rattus rattus atuam como ligação com o ciclo selvagem.

In order to determine Trypanosoma cruzi infection among mammals in Yucatan, Mexico, 372 animals, both wild and synanthropic including carnivores, marsupials and rodents were studied. Serological studies by indirect haemagglutination (IHA) were carried out to detect antibodies to T. cruzi and a parasitological study was also performed (blood smear and histopathology). Of all the animals tested 18.54% were serologically positive, with a significantly higher frequency among the wild ones (33.33%) compared to the synanthropic ones (17.79%). To determine T. cruzi in positive animals, blood was inoculated into a white mouse (webster type) to prove myocardium colonization. The serological and parasitological positivity of these animals, as well as their behavior in the environment, taken together with the socioeconomic and cultural characteristics of the population, suggest that in Yucatan, Mexico, Canis familiaris, Didelphis marsupialis and Rattus rattus act as a link with the wild cycle.