Isolamento de amostras do Trypanosoma cruzi por xenodiagnóstico e hemocultura de pacientes na fase crônica da doença de Chagas

Abstract

Fifty nine chronic chagasic patients were simultaneously submitted to xenodiagnosis and hemoculture for Trypanosoma cruzi samples isolations. The xenodiagnosis was done with 40 Panstrongylus megistus, Triatoma infestans and Dipetalogaster maximus nymphs, performing 120 triatomines. Groups of 10 insects per specie were dissecated and the intestinal content pooled and examined, after previous trituration and homogenization. The microscopically negative material was seed into LIT medium and examined after 20 days. Twenty nine patients were parasitologically proved, being 15 only by xenodiagnosis, 4 only by hemoculture and 10 by both methods. It was discussed the parasitological comprovation difficulties in chronic chagasic patients, the value of the simultaneous utilization of different triatomine species in xenodiagnosis and the hemoculture, in a favorable positive association to the sensitivity increase in the diagnosis' disease. The 49.2% of positivity obtained in this group, visualize approaches like clinic-therapeutic assay and or epidemiological (case-control) with the purpose to investigate a possible association with T. cruzi samples and different clinic forms in Chagas' disease.

Relationship between Trypanosoma cruzi and human chagasic megaesophagus: blood and tissue parasitism.

“…40 This same situation seems to occur with PCR performed in blood, where positive results in different chagasic populations and techniques fluctuate 45-100%. [20][21][22]41,42 The simultaneous application of 2 parasitologic tests increases diagnostic sensitivity, 43,44 but PCR is more sensitive in detecting circulating parasites. Our data indicate 74.5% agreement between positive PCR in blood and the presence of circulating parasites detected by indirect parasitologic tests, which is similar to findings in published data.…”

Characterization of Trypanosoma cruzi Strains Isolated from Chronic Chagasic Patients, Triatomines and Opossums Naturally Infected from the State of Rio Grande do Sul, Brazil

“…Adults of T. infestans captured inside houses and Panstrongylus megistus collected in the peridomiciliar environment by personnel of the National Foundation of Health (FNS), were examined by fresh feces smears and the positive insects were submitted to a xenoculture in LIT for parasite isolation (Bronfen et al 1989). Opossums Didelphis albiventris captured in peridomiciliar areas of Porto Alegre city by the Vector Control Division of the Health and Environment Secretary, were submitted to xenodiagnosis for searching and isolation of T. cruzi.…”

Treatment of congenital Chagas' disease diagnosed and followed up by the polymerase chain reaction.

“…The efficacy of benznidazole was assessed by the PCR, which is considered the parasitologic detection method with highest sensitivity in the chronic phase of the infection. [13][14][15][16][17] The results in Table 3 show that while the serology still remains positive after 3-8 months post-treatment, it is possible to evaluate the effectiveness of the treatment by the PCR, with higher sensitivity as soon as 15 days post-treatment (baby 1).…”

“…Several reports exist on the use of the polymerase chain reaction (PCR) for diagnosis of T. cruzi infection [9][10][11][12][13] and its advantage over parasitologic methods such as direct microscopic observation, 14 hemoculture, 15 and xenodiagnosis 16 because of its high sensitivity. 17 We have found that the PCR, when used with the T. cruzi-specific primers TCZ-1 and TCZ-2, which anneal to a highly repetitive sequence of T. cruzi nuclear DNA, 18 is far more sensitive than direct microscopic observation for the neonatal diagnosis of T. cruzi infection.…”