A preliminary study of platelet hyperactivity in the chronic indeterminate phase of Chagas' disease.

The chronic indeterminate phase of Chagas' disease is asymptomatic despite positive test results for antibodies specific to Trypanosoma cruzi. CD62P-APC (P-selectin) and PAC-1 FITC (GpIIb/IIIa) may improve diagnosis as biomarkers of platelet activity. Nine asymptomatic seropositive subjects, previously untreated, were selected from a blood bank within a year of Chagas' disease detection, in addition to a control group of four. All subjects were evaluated by flow cytometry for CD62P, PAC-1 and CD41, and in a complementary study, by Tissue Doppler Echocardiography for isovolumic relaxation times (IVRT) and E/A ratios. The subjects were classified as positive or negative for CD62P and PAC-1 by a cut off obtained from their mean±2SD. For IVRT and E/A ratios, cut offs were obtained from the American Society of Echocardiography and the European Association of Cardiovascular Imaging recommendations. Fisher's exact test was used for associated findings. Pre-test and post-test probability, sensitivity, specificity, positive and negative predictive values and likelihood ratios were calculated. Abnormalities were expressed as platelet hyperactivity and ventricular dysfunction in CD62P, PAC-1, IVRT and E/A ratios. CD62P appears to have greater sensitivity (0.75) and PAC-1, more accurate specificity (0.75), which may explain thrombotic events in Chagas' disease. We recommend the use of CD62P and PAC-1 as biomarkers of platelet hyperactivity in patients in the chronic indeterminate phase of Chagas' disease.

[Seroprevalence of Trypanosoma cruzi antibodies and associated risk factors among the population under 18 years of age in Veracruz, Mexico]. / Seroprevalencia de anticuerpos contra Trypanosoma cruzi y su asociación con factores de riesgo en menores de 18 años de Veracruz, México.

OBJECTIVES: To determine the prevalence of Trypanasoma cruzi antibodies among the population under 18 years of age in the state of Veracruz, Mexico, and to identify risk factors associated with housing conditions and vector presence and distribution. METHODS: A cross-sectional, epidemiological study of the population under 18 years of age living in 10 of the 11 health districts of the state of Veracruz, Mexico, from 2000 to 2001. Presence of T. cruzi antibodies was determined by hemagglutination inhibition test (HAI) and enzyme-linked immunosorbent assays (ELISA) of serum samples spotted on filter paper, and confirmed by HAI, ELISA, and indirect immunofluorescence assay (IFA) on serum samples. A questionnaire was administered to determined housing conditions, and entomological indices for triatomines were calculated for both the intra- and peridomiciliary areas. The results were analyzed using bifactorial and multifactorial unconditional logistic regression. RESULTS: Of the 150 individuals presenting an initial reaction, 14 were confirmed positive (5 by HAI, ELISA and IFA; 6 by HAI and ELISA, and 3 by ELISA and IFA), for a total prevalence rate of 0.91% (95% CI: 0.85-0.94). All of the confirmed-positive cases were from five of 14 health districts, with the Tuxpan district having the highest prevalence rate: 5.2% (95%CI: 1.2-9.0). Risk factors included having noticed cracks in the house walls and gaps in the roof. The only species of vector captured was Triatoma dimidiata. The entomologic indices for infestation, colonization, and natural infection were: 10.9%, 50.0%, and 9.0%, respectively. CONCLUSIONS: Active, vector-borne transmission of T. cruzi was confirmed in the state of Veracruz, Mexico, with an overall antibody seroprevalence rate of 0.19% among the population under 18 years of age. Seroprevalence rates among this segment of the population, which serves as a sentinel group, should be closely monitored to determine if more stringent methods of vector control and epidemiological surveillance are needed.

Seroprevalencia de anticuerpos contra Trypanosoma cruzi y su asociación con factores de riesgo en menores de 18 años de Veracruz, México / Seroprevalence of Trypanosoma cruzi antibodies and associated risk factors among the population under 18 years of age in Veracruz, Mexico

OBJETIVOS: Determinar la prevalencia de anticuerpos contra Trypanosoma cruzi en menores de 18 años del estado de Veracruz, México, e identificar los factores de riesgo asociados con las características de la vivienda y la presencia y distribución del agente transmisor. MÉTODOS: Estudio epidemiológico transversal en la población menor de 18 años que vivía en 10 de las 11 jurisdicciones sanitarias del estado de Veracruz, México, entre 2000 y 2001. La presencia de anticuerpos contra T. cruzi se determinó mediante una prueba de hemaglutinación indirecta (HAI) y un ensayo inmunoenzimático indirecto tipo ELISA en muestras de suero tomadas en papel de filtro y se confirmaron mediante las pruebas de HAI, ELISA e inmunofluorescencia indirecta (IFI) en muestras de suero. Se aplicó un cuestionario para evaluar las condiciones de la vivienda y se calcularon los índices entomológicos de triatominos intra y peridomiciliarios. Los resultados se evaluaron mediante análisis bifactorial y multifactorial por regresión logística no condicional. RESULTADOS: De las 150 personas inicialmente reactivas, 14 resultaron positivas (5 mediante la prueba de HAI, ELISA e IFI; 6 por HAI y ELISA y 3 por ELISA e IFI), para una prevalencia general de 0,91 por ciento (IC95 por ciento: 0,85 por ciento a 0,94 por ciento). Los casos positivos residían en cinco jurisdicciones sanitarias y la mayor prevalencia se encontró en Tuxpan: 5,2 por ciento (IC95 por ciento: 1,2 por ciento a 9,0 por ciento). Los factores de riesgo fueron el haber visto chinches dentro de la vivienda y los techos con fisuras. La única especie del agente transmisor capturada fue Triatoma dimidiata. Los índices entomológicos de infestación, colonización e infección natural fueron: 10,9 por ciento, 50,0 por ciento y 9,0 por ciento, respectivamente. CONCLUSIONES: Se confirmó la transmisión vectorial activa de la infección en el estado de Veracruz, México, con una seroprevalencia general de anticuerpos contra...

OBJECTIVES: To determine the prevalence of Trypanasoma cruzi antibodies among the population under 18 years of age in the state of Veracruz, Mexico, and to identify risk factors associated with housing conditions and vector presence and distribution. METHODS: A cross-sectional, epidemiological study of the population under 18 years of age living in 10 of the 11 health districts of the state of Veracruz, Mexico, from 2000 to2001. Presence of T. cruzi antibodies was determined by hemagglutination inhibition test (HAI) and enzyme-linked immunosorbent assays (ELISA) of serum samples spotted on filter paper, and confirmed by HAI, ELISA, and indirect immunofluorescence assay (IFA) on serum samples. A questionnaire was administered to determined housing conditions, and entomological indices for triatomines were calculated for both the intra- and peridomiciliary areas. The results were analyzed using bifactorial and multifactorial unconditional logistic regression. RESULTS: Of the 150 individuals presenting an initial reaction, 14 were confirmed positive (5 by HAI, ELISA and IFA; 6 by HAI and ELISA, and 3 by ELISA and IFA), for a total prevalence rate of 0.91 percent (95 percent CI: 0.85-0.94). All of the confirmed-positive cases were from five of 14 health districts, with the Tuxpan district having the highest prevalence rate: 5.2 percent (95 percentCI: 1.2-9.0). Risk factors included having noticed cracks in the house walls and gaps in the roof. The only species of vector captured was Triatoma dimidiata. The entomologic indices for infestation, colonization, and natural infection were: 10.9 percent, 50.0 percent, and 9.0 percent, respectively. CONCLUSIONS: Active, vector-borne transmission of T. cruzi was confirmed in the state of Veracruz, Mexico, with an overall antibody seroprevalence rate of 0.19 percent among the population under 18 years of age. Seroprevalence rates among this segment of the population, which serves as a sentinel group,...