Performance levels of four Latin American laboratories for the serodiagnosis of Chagas disease in Mexican sera samples

In nearly all of the previous multicentre studies evaluating serological tests for Trypanosoma cruzi infection, sera samples from Central or South American countries have been used preferentially. In this work we compared the reliability of the serological tests using Mexican sera samples that were evaluated in four independent laboratories. This included a reference laboratory in Brazil and three participant laboratories, including one in Central America and two in Mexico. The kappa index between Brazilian and Honduran laboratories reached 1.0 and the index for the Mexican laboratories reached 0.94. Another finding of this study was that the source of antigen did not affect the performance of the serological tests.

Cardiopatía chagásica crónica en el Hospital General de Zona No 24 IMSS. Poza Rica, Veracruz / Chronic Chagasic Cardiomyopathy at the Hospital General de Zona no. 24 IMSS. Poza Rica, Veracruz

Northern Veracruz has conditions, biotic and abiotic, to support Triatomine bugs and vectorial transmission of Trypanosoma cruzi to human beings. Therefore we explore seroprevalence of antibodies to this parasite and the presence of Chronic Chagasic Cardiopathy (CCC) at Cardiology ward in a General Hospital serving North of Veracruz State, and neighbord states Hidalgo, Puebla San Luis Potosi and Tamaulipas. MATERIAL AND METHODS: We search for consecutive adult patients attending outpatient and beds assigned to Cardiology between March through September, 2003. An epidemiology questionnaire, clinical work up, chest roentgenogram, 12 lead peripheral EKG and transthoracic echocardiogram were performed in 240 female/males patients. All of them were bled to blindly search for T. cruzi antibodies. RESULTS: Seroprevalence was 8%, 49 cases of dilated cardiomyopathy were diagnosed 23 attributed to chronic diseases such as systemic hypertension diabetes mellitus or ischemic heart disease 12 with idiopathic disease and 14 (29%) had CCC. The latter accumulated epidemiologic features suggestive of vectorial infection. Four additional individuals without CCC but having specific antibodies were considered indeterminate Chagasic cases. DISCUSSION AND CONCLUSIONS: This case series identify American Trypanosomiasis among 19 people attending a Cardiology Service, and 14 of them had a severe heart disease linked to progressive and fatal course. This observation points out that Chagas disease could be a regional public health problem in Northern Veracruz.

Blood transfusion and iatrogenic risks in Mexico city: anti-Trypanosoma cruzi seroprevalence in 43,048 blood donors, evaluation of parasitemia, and electrocardiogram findings in seropositive

Iatrogenous transmission of Trypanosoma cruziby blood transfusion was suggested as a potential risk by Pellegrino (1949). Seropositive blood donors in Mexico were first reported in 1978, however, limited information is available due to small sampling, the use of heterogeneous serologic assays, and geographically limited studies. A wide survey carried out in 18 out of the 32 states of Mexico, showed a national mean of 1.6 percent seropositive among 64,969 donors, ranging from 0.2 to 2.8 percent. In the present study, we have screened 43,048 voluntary blood donors in a period of five years at the Instituto Nacional de Cardiología I. Chávez, a concentration hospital located in Mexico city which serves mainly the metropolitan area and accepts from all over the country. Standardized ELISA and IIF were used to identify seropositive individuals in addition to hemoculture, PCR and standard 12 lead ECG tests that were applied to a group of seropositive patients (29/161). The result showed a seropositivity of 0.37 percent (161/43,048). From the group of seropositive individuals 40 percent (12/29) were potential carriers of T. cruzi at the donation time and 5/29 had subclinical ECG abnormalities. Parasitological tests performed in 70 erythrocyte and platelet fractions from seropositive units (70/161) showed negative results. Our findings strongly support T. cruzi screening in the transfusion medicine practice and identify subclinical heart disease among seropositive blood donors.

Electrocardiographic findings in Mexican chagasic subjects living in high and low endemic regions of Trypanosoma cruzi infection

In México the first human chronic chagasic case was recognized in 1940. In spite of an increasing number of cases detected since that time, Chagas disease in México has been poorly documented. In the present work we studied 617 volunteers subjects living in high and low endemic regions of Trypanosoma cruzi infection with seroprevalence of 22 percent and 4 percent respectively. Hemoculture performed in those seropositive subjects failed to demonstrate circulating parasites, however polymerase chain reaction identified up to 60 percent of them as positives. A higher level of anti-T. cruzi antibodies was observed in seropositive residents in high endemic region, in spite of similar parasite persistence (p < 0.05). On standard 12 leads electrocardiogram (ECG) 20 percent to 22 percent seropositive individuals from either region showed right bundle branch block or ventricular extrasystoles which were more prevalent in seropositive than in seronegative individuals (p < 0.05). In conclusion, the frequency or type of ECG abnormality was influenced by serologic status but not by endemicity or parasite persistence. Furthermore, Mexican indeterminate patients have a similar ECG pattern to those reported in South America

Seroprevalence of human Trypanosoma cruzi infection in diferent geografic zones of Chiapas, Mexico

Foi feito um estudo sorológico em quatro zonas geográficas do estado de Chiapas México. Foram colhidas 1333 amostras dos habitantes das 13 comunidades situadas na costa, na região central montanhosa, na floresta lacandona e na região chamada mesochiapas. Cento cinqüenta e uma pessoas (11,3 por cento) foram identificadas como soropositivas. A infecção pelo Trypanosoma cruzi teve a influência da geografia local. Na floresta lacandona nas montanhas centrais, foi encontrada uma prevalência de 32,1 e 13,8 por cento respectivamente, mais que na costa 1,2 por cento. Na zona de mesochiapas não foi encontrada nenhuma pessoa com sorologia positiva entre 137 estudadas. Como encontramos sorologia positiva em crianças menores de 10 anos, pensamos que exista uma transmissão ativa contínua. Na costa foi reconhecido o vetor Triatoma dimidiata e na floresta Lacandona o Rhodnius prolixus

IgG subclass reactivity to Trypanosoma cruzi in chronic chagasic patients / Reactividad de subclases de IgG a trypanosoma cruzi en pacientes crónicos chagásicos

La respuesta humoral anti-Trypanosoma cruzi y el isotipo de inmunoglobulina presente en individuos con enfermedad de Chagas se ha estudiado en relación con las distintas manifestaciones clínicas. Se ha encontrado que títulos altos de IgG anti-T. cruzi específicos estan preferentemente presentes en pacientes con daño cardiaco, mientras que en la forma digestiva es la IgA anti- T. cruzi. En el presente trabajo se estudiaron 12 pacientes consecutivos con diagnóstico de enfermedad de Chagas Todos ellos tenían una evaluación clínica completa y estudios electrocardiográfico, ecocardiográfico, ventriculografía y coronariografía, además del estudio serológico de detección de anticuerpos IgG anti-T. cruzi. En ellos se analizó el perfil de subclases de IgG anti-T. cruzi.Todos los pacientes provenían de áreas rurales de México y algunos habían vivido allí siete o hasta 65 años. En 7/12 (58 por ciento) de ellos presentaron dilatación ventricular izquierda con una dimensión final sistólica por arriba de 42 mm y con una fracción de expulsión por abajo del 50 por ciento en 7/12 (58 por ciento). Los títulos de anticuerpos de IgG1 e IgG2 anti-T. cruzi fueron más altos que los de IgG3, mientras que los niveles de IgG4 anti-T. cruzi, si bien fueron positivos, resultaron ser consistetemente los más bajos. La expresión de las cuatro subclases de IgG anti-T. cruzi sugiere que se induce una respuesta mixta tipo Th1/Th2 en estos pacientes chagásicos crónicos. Aunque el tamaño de muestra estudiado es pequeño, encontramos que los niveles altos de IgG2 anti-T. cruzi presentaban una tendencia a asociarse con el grado de cardiomegalia.

American trypanosomiasis (Chagas'Disease) and blood banking in Mexico City: seroprevalance and its potential transfusional transmission risk

Background. American trypanosomiasis (Chagas' disease), an anthropozoonosis fairly common in rural Latin American, has become an urban disease due to continuous migration, intra- and internationally. Blood transfusion, the second important pathway for transmission, increases its impact. Recognition of seropositive subjects among blood donors is now recommended, and clinical and serological screening enforced. Maneuvers to inactivate or remove Trypanosoma cruzi present in collected blood are recommended. Methods. We surveyed voluntary donors at the National Institute of Cardiology in Mexico City in of anti-T. cruzi by indirect immunofluorescence, ELISA, and Western blot analysis. Seropositive donors were identified and tested for immunoglobulin. We used types and fractions of donated blood to extract DNA and perform the PCR technique using kinetoplast primers seeking parasite DNA in blood. Results. After 3,300 donors were screened, we identified 10 seropositive subjects (0.3 percent). These subjects were considered as indeterminate chagasic patients, came mainly from rural areas, and had IgG (100 percent) and IgA (30 percent) antibodies aginst a crude extract as well as a recombinant T. cruzi antigen. Identification of parasite DNA in red cell and platelet fraction was achieved from eight blood units. Conclusions. The present data provide evidence that blood donors at an urban hospital are seropositive for T. cruzi and at least 50 percent of donors carry the parasite potentially able to transmit T. cruzi in their cellular blood products. Serological screening should be included in routine blood-banking. It is also necessary to adopt measures to inactivate or eliminate organisms in donated blood