[Identification of immunodominant components of an isolate of Trypanosoma cruzi by immunoblot and its standardization for diagnostic purposes]. / Identificación de componentes inmunodominantes de un aislado de Trypanosoma cruzi por inmunoblot y su estandarización con fines diagnósticos.

INTRODUCTION: Conventional serology was used for the detection of Trypanosoma cruzi infection, with diverse sensitivity and specificity results. Due to the number of samples with doubtful results, it is necessary to develop additional confirmation tests such as the immunoblot. OBJECTIVE: The aim of this study was identify major immunogenic proteins of T. cruzi isolate and establish criteria for immunoblot positivity with diagnostic purposes. METHODS: Immunoblot initial standardization was performed, determining optimal concentrations of antigen, serum, and second antibody. Thirty-five positive and thirty negative sera were assayed to evaluate different criteria of positivity and determine which provides greater sensitivity and specificity. RESULTS: Immunoblot of T. cruzi positive sera shared a rich pattern of components with molecular weights between 10-250 kDa. Twelve components had a recognition rate higher than 50%, of which the polypeptides of 27, 32, 34, and 38 kDa were close to 100%. Of the positivity criteria evaluated, the recognition of the components of 27 and 32 kDa provided sensitivity and specificity of 100%. DISCUSSION: The Immunoblot is suitable for confirmation of infection by T. cruzi, so it is strongly recommended for confirmation and discrimination of discordant cases.

[Chagas disease in Mexico. Report of two acute cases]. / Presentación de dos casos de enfermedad de Chagas aguda en México.

Two cases of acute Chagas disease in schoolchildren of 6 and 13 years of age, both with the clinical features of Romaña's sign, regional lymphadenopathy, and fever, have a history of coexistence and the bite of the transmitter, and live in housing constructed with material considered at risk for infestation by the vector; i.e. roof and walls with palma/zacate (palm tree, grass leaves), dirt floor, and inadequate illumination and ventilation. The parasitological diagnosis of both cases was established by identification of trypomastigotes of Trypanosoma cruzi in blood smears and the parasite was isolated in one of them. Benznidazole treatment was administered according to the guidelines of the WHO/PAHO for this disease. The presence of acute Chagas disease in rural areas confirms the active transmission of the parasite, so surveillance and epidemiological controls should be applied. The importance of these cases is that T. cruzi infection is symptomatic in 5% of cases, which implies that a high percentage of cases of infection appear asymptomatic and are not being diagnosed in our country.

Chagas disease as a cause of symptomatic chronic myocardopathy in Mexican children.

We report the first case series of children in Mexico living with symptomatic Chagas disease causing chronic myocardopathy. The findings suggest that children with Chagas disease may develop symptomatic chronic myocardopathy earlier than previously recognized. Our findings emphasize the importance of longitudinal cardiologic follow-up of all children identified with acute Chagas disease.In a cohort of 826 children from the state of Queretaro in Mexico, 11 were identified with positive serology (ELISA and IFI) for Chagas and were tested for electrocardiogram alterations and symptoms and signs. Four children had ECG alterations with 3 of these reporting signs and symptoms associated with the chronic phase of Chagas disease (27%; 95% CI: 6%-61%). The most common chronic symptom was chest pain, with one child also reporting dyspnea and tachycardia.