ABSTRACT
Trypanosoma cruzi I, a discrete typing unit (DTU) found in human infections in Venezuela and other countries of the northern region of South America and in Central America, has been recently classified into five intra-DTU genotypes (Ia, Ib, Ic, Id, Ie) based on sequence polymorphisms found in the spliced leader intergenic region. In this paper we report the genotype identification of T. cruzi human isolates from one outbreak of acute orally acquired Chagas disease that occurred in a non-endemic region of Venezuela and from T. cruzi triatomine and rat isolates captured at a guava juice preparation site which was identified as the presumptive source of infection. The genotyping of all these isolates as TcId supports the view of a common source of infection in this oral Chagas disease outbreak through the ingestion of guava juice. Implications for clinical manifestations and dynamics of transmission cycles are discussed.
Subject(s)
Chagas Disease/epidemiology , Chagas Disease/parasitology , Disease Outbreaks , Genes, Protozoan , Trypanosoma cruzi/genetics , Animals , Base Sequence , Beverages/parasitology , Chagas Disease/transmission , Genotype , Genotyping Techniques , Humans , Molecular Sequence Data , Psidium , Rats/parasitology , Schools , Sequence Alignment , Trypanosoma cruzi/classification , Trypanosoma cruzi/isolation & purification , Venezuela/epidemiologyABSTRACT
BACKGROUND & OBJECTIVE: There are few reports of Coccus nucifera (Palmae) infestation by triatomines (Hemiptera, Reduviidae, Triatominae), vectors of Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae), the causal agent of American Trypanosomiasis. The aim of this study was to determine if this palm is an appropriate ecotope for Rhodnius prolixus and Triatoma maculata, the main vectors in Venezuela. METHODS: Dry and green leaves, humid debris, interfoliaceus meshes and bracts from C. nucifera from north-eastern Venezuela were examined for the presence of triatomines. Samples of the intestinal content of vectors, macerated in isotonic saline solution and haemolymph were examined microscopically for the presence of Trypanosoma spp. The parasites were isolated and characterized using biological parameters and PCR. Triatomine blood meal sources were determined using ELISA. RESULTS: A total of 14 palms were examined in which viable eggs of both species of vectors were found in 13 palms (92.85%). A total of 242 R. prolixus and 144 T. maculata adults were collected, of which 98% of R. prolixus and 70% of T. maculata individuals were infected by T. cruzi (TcI genotype) and 13% of R. prolixus individuals showed a mixed infection with T. rangeli, the other American trypanosome. ELISA testing for possible triatomine blood-meal sources revealed that these vectors are essentially eurytrophic and zoophilic, although R. prolixus also eventually used human blood as a nourishment source. INTERPRETATION & CONCLUSION: The results obtained suggest that C. nucifera is an appropriate vegetal niche for these triatomine species in Venezuela. The presence of this commercial palm may represent a useful environmental bioindicator of risk for Chagas disease.
Subject(s)
Cocos/parasitology , Insect Vectors/parasitology , Triatominae/parasitology , Trypanosoma cruzi/isolation & purification , Animals , Chagas Disease/parasitology , Humans , Plant Diseases/parasitology , Trypanosoma cruzi/genetics , VenezuelaABSTRACT
Dos ejemplares de Panstrongylus rufotuberculatus fueron capturados en una vivienda de El Hatillo, estado Miranda. En ambos se confirma la presencia de Trypanosoma cruzi. Se estudian algunos parámetros biológicos para estimar el comportamiento de uno de los aislados (Pr), encontrándose que tanto el cultivo en medios acelulares como la inoculación en ratones fueron exitosos. Así mismo, 73,3% de los Rhodnius de laboratorio se infectaron y 30,6% de los parásitos presentaron metaciclogénesis, mientras que in vitro se obtuvo 25,5%. La identificación molecular correspondió a T. cruzi. Este hallazgo es importante debido a la posible emergencia de esta especie silvestre que por alteración antrópica de sus hábitats naturales puede estar en proceso de dispersión, penetración y domiciliación de las viviendas, implicando la posibilidad de transmisión del parásito al ser humano y animales domésticos.
Two specimens of Panstrongylus rufotuberculatus were captured in a house in El Hatillo, Estado Miranda. In both specimens the presence of Trypanosoma cruzi was confirmed. We studied some biological parameters for estimating the behavior of the isolates, finding in both that cell-free culture media as inoculation in mice were successful. Also, 73.3% of Rhodnius prolixus fed on infected mice became infected and 30.6% of the parasites developed to metacyclic forms whereas in vitro only 25.5% was obtained. Furthermore, the molecular identification corresponded to T. cruzi. This finding is important due to the possible emergence of wild species by anthropogenic alteration of their natural habitats, and this may become a process of dispersion, penetration and clearance of houses, implying the possibility of transmitting the parasite to humans and pets.
