A simplified method for sample collection and DNA isolation for polymerase chain reaction detection of Trypanosoma rangeli and Trypanosoma cruzi in triatomine vectors.

Due to the overlapping distribution of Trypanosoma rangeli and T. cruzi in Central and South America, sharing several reservoirs and triatomine vectors, we herein describe a simple method to collect triatomine feces and hemolymph in filter paper for further detection and specific characterization of these two trypanosomes. Experimentally infected triatomines feces and hemolymph were collected in filter paper and specific detection of T. rangeli or T. cruzi DNA by polymerase chain reaction was achieved. This simple DNA collection method allows sample collection in the field and further specific trypanosome detection and characterization in the laboratory.

Metaciclogênese do Trypanosoma cruzi como parâmetro de interação do parasita com o triatomíneo vetor / The metacyclogenesis of Trypanosoma cruzi as a parameter of parasite interaction with the triatomid vector

Triatoma infestans infectados por três amostras do Trypanosoma cruzi permitiram observar: 1) variabilidade numérica de metacíclicos obtidos de cada amostra após diferentes períodos de infecção; 2) diferenças na perda da infecção de acordo com a amostra infectante e 3) a relação entre o número de parasitas ingeridos e metacíclicos obtidos posteriormente.

Infection of Triatoma infestans with three different strains of Trypanosoma cruzi permited to observe: 1) numerical variability of metacyclics obtained after different times; 2) the differences of loss of infection according to each strain; 3) the relationship between ingested parasites and later obtained metacyclics.

Human immune response to triatomine embryo extract.

Dipetalogaster maximus embryo extracts were used to stimulate peripheral blood mononuclear cells (PBMC) and in ELISA with sera either from Trypanosoma cruzi infected or non-infected individuals. The results showed that there was significant proliferative response and high antibody, titers in sera of chagasic patients.

[Xenodiagnosis and criteria to assess the level of parasitemia in chronic chagasic patients]. / O xenodiagnóstico e os critérios para avaliar o nível de parasitemia do paciente chagásico crônico.

Xenodiagnosis sensibility and its relation to Chagas' disease chronic phase parasitemia was verified in 104 patients. The nymphs of the triatomine species, simultaneously utilized in the xenodiagnosis of these patients, divided into two groups, were examined in different ways. The positivity rates achieved in the two groups (40.0% and 42.4%) and the individual positivity rates suggest a reavaliation in what is called "quantification of the chronic chagasic patient parasitemia", considering the methodology used in the xenodiagnosis examinations.

Interacao do Trypanosoma cruzi com diferentes vetores: uso para o xenodiagnostico. / Interaction of Trypanosoma cruzi with different vectors:use for xenodiagnosis

Foram estudadas as diferencas de interacao (diferenciacao e multiplicacao) das cepas Y e CL de Trypanosoma cruzi, consideradas "polares", junto a Triatoma infestans, Panstrongylys megistus e Dipetalogaster maximus. Concluiu-se que o T. infestans apresenta em suas populacoes cerca de 40% de individuos com acentuada resistencia a infeccao pela cepa Y.O P.megistus foi considerado um bom vetor onde se verificou pequena perda de infeccao para ambas as cepas e boa diferenciacao. Melhor desenvolvimento e diferenciacao para ambas as cepas foi observado em D. maximus e dai sua indicacao para xenodiagnosticos. Os autores concluem pela possibilidade da presenca de fatores de resistencia a infeccao e tambem de inibidores de diferenciacao como responsaveis por uma boa ou ma interacao parasito-vetor

A case study of xenodiagnosis.

Estudo de um caso de xenodiagnostico em paciente com doenca de Chagas agudo. A suscetibilidade do D. maximus para a cepa de Barreiras do T. cruzi foi estudada com 100 ninfas do terceiro estagio alimentadas em uma paciente com Doenca de Chagas agudo. A taxa de infeccao nestes triatomineos foi tao alta que nao foi possivel identificar um grupo refratario para a criacao

Attempts to produce megasyndrome in mice using stocks of Trypanosoma cruzi associated with megaoesophagus in man.

Two stocks of Trypanosoma cruzi isolated from patients with advanced megaoesophagus produced megastomach in chronically infected mice. The mice showed evidence of stomach dilatation and a delay in intestinal transit time. These findings are discussed in the light of the hypothesis that regional variations in T. cruzi determines mega formation in man.