Trypanosoma cruzi parasitemia observed in immunocompromised patients: the importance of the artificial xenodiagnosis

Trypanosoma cruzi parasitemia observed in immunocompromised patients (transplant or positive HIV) occurred more frequently by the artificial xenodiagnosis method (10/38) compared with hemoculture (2/38), given the same quantity of blood. Other ways of diagnosis, like mice inoculation (5/38), QBC and buffy coat (2/38), were evaluated also. This result showed the importance of the artificial xenodiagnosis. The other techniques increased only one more patient positive.

[An attempt to detect Trypanosoma cruzi in the peripheral blood of patients with Chagas' disease, in chronic phase, using quantitative buffy coat (QBC)]

Taking for granted the sensitivity of the Quantitative Buffy Coat (QBC) system, as documented in a murine experimental model, we assayed to detect Trypanosoma cruzi in the peripheral blood of 100 patients with Chagas disease in its chronic phase. By means of the method, no positivity occurred, evently as a consequence of small parasitemias, undetectable by this technique as assessed by the cases in consideration.

[Evaluation of the possible influence of Montenegro's intradermal reaction on a serological assay for the diagnosis of American cutaneous leishmaniasis]

Influence of Montenegro skin test for American tegumentar leishmaniasis was evaluated to verify possible interference in serological diagnosis for this disease, performed by immunoenzymatic assay (ELISA). If this interference could occur, it would hamper scientific, epidemiological and patient care; happily we did not find any interference on serological diagnosis by performance of skin testing.