Jamiro da Silva Wanderley

Use of a nested polymerase chain reaction (N-PCR) to detect Trypanosoma cruzi in blood samples from chronic chagasic patients and patients with doubtful serologies

Chagas disease, caused by Trypanosoma cruzi, is an important endemic illness in Latin America. Serologic tests for T. cruzi detection in blood are sensitive, but their specificity is unsatisfactory. Direct detection of parasites in blood, either by xenodiagnosis or hemoculture, is highly specific but of low sensitivity. Molecular assays such as the Polymerase chain reaction (PCR), which amplifies certain repetitive sequences of nuclear DNA has been used as a good alternative tool for T. cruzi detection in human blood. The present study aimed to test PCR diagnosis in chagasic chronic patients and doubtful serologic patients attended in GEDOCH (Chagas Disease Study Group/UNICAMP, Brazil). A 149 bp fragment originated from nuclear DNA was specifically detected in chronic chagasic patients. The results of these tests were compared with serologic diagnosis performed using standard techniques and xenodiagnosis. We found that 43 out of 50 patients previously serodiagnosed as chagasic were positive using the N-PCR method. Thirteen of 30 patients with doubtful serologic results were confirmed as positive by N-PCR. Our results suggest that the N-PCR may be a complementary tool to serology in the diagnosis of Chagas disease, and that it is usefull for parasite detection in patients with chronic disease and patients with doubtful serologic results.

Serological profiles and evaluation of parasitaemia by PCR and blood culture in individuals chronically infected by Trypanosoma cruzi treated with benzonidazole

Objective  To evaluate the serological and parasitological status of patients with chronic Chagas disease (CD) after chemotherapy with benzonidazole.

Evidence of Chagas disease in seronegative Brazilian patients with megaesophagus.

BACKGROUND After 100 years of research, Chagas disease (CD) remains an important public health problem in Latin America. The symptomatic chronic phase is usually characterized by cardiac or digestive involvement and diagnosis currently relies on the measurement of Trypanosoma cruzi-specific antibodies produced in response to the infection. However, the detection of parasite DNA in seronegative persons has been reported. METHODS The prevalence of CD in a population with esophageal disorders was assessed by conventional serology. We also detected T. cruzi DNA in blood samples of seronegative and inconclusive patients by nested polymerase chain reaction (N-PCR). RESULTS The seroprevalence of CD determined by conventional serologic tests (indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA)) was 79% in 513 patients with esophageal disorders. Out of 41 blood samples, N-PCR was positive in 31 (76%) cases for which serology was negative or inconclusive. CONCLUSIONS As all patients presented with clinical signs suggestive of the digestive form of CD and most of them were born in endemic areas, we highlight the importance of improving diagnosis of the disease and the implications for blood bank screening. Our data suggest that N-PCR is effective in the detection of T. cruzi DNA in patients with inconclusive or negative serology, and it may eventually be useful in the determination of the etiology of megaesophagus.

Apresentação clínica da doença de Chagas crônica em indivíduos idosos

This study had the aim of evaluating the clinical presentation of chronic Chagas disease among the elderly. It was a retrospective analysis of clinical records at an outpatient referral service. The sample was divided into two groups: elderly (>or= 60 years old) and non-elderly. Sex, comorbidities, clinical form, electrocardiogram and serological titers were evaluated. In the elderly group (61 cases), the mean age was 66.03+/-5 years; 67.2% were female; 59% presented comorbidities (most frequently systemic arterial hypertension, in 39.3%); 1.6% had the indeterminate clinical form, 88.5% the cardiac form and 36% the digestive form; and abnormalities were frequently found on electrocardiograms: 41% presented anterosuperior left bundle branch block (AS-LBBB), 32.8% presented right bundle branch block (RBBB) and 22.9% presented ventricular ectopic beats (VEB). In the non-elderly group (61 cases), the mean age was 39.30+/-8.36 years; 54.1% were female; 50.8% presented comorbidities (most frequently systemic arterial hypertension, in 26.2%); 18% had the indeterminate clinical form (p<0.05), 78.7% the cardiac form and 32.8% the digestive form; and abnormalities were frequently found on electrocardiogram: 24.6% presented AS-LBBB, 21.3% RBBB and 18% VEB. It was concluded that there were no clinical differences between elderly and non-elderly Chagas patients. The indeterminate clinical form predominated in patients less than 60 years old.