ABSTRACT
Entre más de 100 especies de triatominae (hemiptera: ruduviidae) descritas en el Nuevo Mundo, triatoma sordida es considerada de significancia epidemiológica como vector de trypanosoma cruzi por su amplia área de distribución y su tendencia para invadir ambientes domésticos.
Subject(s)
Humans , Male , Female , Triatoma , Trypanosoma cruzi , BoliviaABSTRACT
Triatoma infestans es el vector principal de la enfermedad de Chagas en Bolivia y, excepto algunos focos silvestres de esta especie descrito en el departamento de Cochabamba, existen hasta ahora pocos estudios de las otras especies silvestres.
Subject(s)
Humans , Trypanosoma cruzi , BoliviaABSTRACT
Triatoma sordida is the second species of Triatominae considered of epidemiological significance in Bolivia. Associated with Triatoma infestans in various regions, it is as yet the only triatomine species established in human dwellings in localities of Velasco province, Department of Santa Cruz. This domestication is considered as primary. Flagellate parasites were detected in 16.2% of domiciliary T. sordida and the kDNA-PCR confirmed the presence of Trypanosoma cruzi. Frequencies of T. cruzi clonets 20 and 39, common clonets in Bolivian domestic cycle (T. infestans), were established by their direct detection in feces using PCR and hybridization. These clonets present low frequencies in T. sordida and synanthropic mammals. Forty-six stocks were isolated and analysed by multilocus enzyme electrophoresis (MLEE). The MLEE showed a higher clonal diversity than in T. infestans domestic cycle and the genotypes were clustered in the two principal lineages of T. cruzi. Within each lineage, a broad variability was observed. Mixture of genotypes was mostly observed in mammals. The large diversity of T. cruzi in this cycle should be related to its sylvatic origin. Moreover, the current limited sample of stocks suggests a lineage association with specific hosts.
Subject(s)
Triatoma/parasitology , Trypanosoma cruzi/genetics , Animals , Bolivia , Cats , Dogs , Genotype , Humans , Polymerase Chain Reaction , Polymorphism, Genetic , Rats , Trypanosoma cruzi/isolation & purificationABSTRACT
The role of Triatoma sordida in the domestic transmission of Trypanosoma cruzi was assessed in 7 rural localities in Velasco Province, Department of Santa Cruz, Bolivia. Tri. sordida, the only triatomine species identified in these localities, was found inside 58.0% of houses but not in large numbers (3.1 bugs per infested house on average). A total of 220 faecal samples from domiciliary bugs was examined microscopically and by the polymerase chain reaction for the presence of trypanosomes: 21.4% were infected. Analysis of blood meals of domiciliary Tri. sordida showed that humans were the commonest host (70.4%), followed by chickens and dogs. Four of 418 persons tested were seropositive for Tryp. cruzi. Only 2 of a second group of 62 persons living in dwellings infested by Tri. sordida were seropositive. Tryp. cruzi infection was demonstrated in dogs and domestic rats. Three other species of small mammals were found to be infected with trypanosomes. In our study area, domestic Tri. sordida are mainly incriminated in the transmission of Tryp. cruzi to synanthropic animals, whereas transmission to humans is very rare. The presence in houses of small populations of Tri. sordida infected with Tryp. cruzi is therefore currently insufficient for this insect to constitute a major epidemiological risk factor.
