Diagnostic reliability of an immunochromatographic test for Chagas disease screening at a primary health care centre in a rural endemic area.

Many patients with Chagas disease live in remote communities that lack both equipment and trained personnel to perform a diagnosis by conventional serology (CS). Thus, reliable tests suitable for use under difficult conditions are required. In this study, we evaluated the ability of personnel with and without laboratory skills to perform immunochromatographic (IC) tests to detect Chagas disease at a primary health care centre (PHCC). We examined whole blood samples from 241 patients and serum samples from 238 patients. Then, we calculated the percentage of overall agreement (POA) between the two groups of operators for the sensitivity (S), specificity (Sp) and positive (PPV) and negative (NPV) predictive values of IC tests compared to CS tests. We also evaluated the level of agreement between ELISAs and indirect haemagglutination (IHA) tests. The readings of the IC test results showed 100% agreement (POA = 1). The IC test on whole blood showed the following values: S = 87.3%; Sp = 98.8%; PPV = 96.9% and NPV = 95.9%. Additionally, the IC test on serum displayed the following results: S = 95.7%; Sp = 100%; PPV = 100% and NPV = 98.2%. Using whole blood, the agreement with ELISA was 96.3% and the agreement with IHA was 94.1%. Using serum, the agreement with ELISA was 97.8% and the agreement with IHA was 96.6%. The IC test performance with serum samples was excellent and demonstrated its usefulness in a PHCC with minimal equipment. If the IC test S value and NPV with whole blood are improved, then this test could also be used in areas lacking laboratories or specialised personnel.

Diagnostic reliability of an immunochromatographic test for Chagas disease screening at a primary health care centre in a rural endemic area

Many patients with Chagas disease live in remote communities that lack both equipment and trained personnel to perform a diagnosis by conventional serology (CS). Thus, reliable tests suitable for use under difficult conditions are required. In this study, we evaluated the ability of personnel with and without laboratory skills to perform immunochromatographic (IC) tests to detect Chagas disease at a primary health care centre (PHCC). We examined whole blood samples from 241 patients and serum samples from 238 patients. Then, we calculated the percentage of overall agreement (POA) between the two groups of operators for the sensitivity (S), specificity (Sp) and positive (PPV) and negative (NPV) predictive values of IC tests compared to CS tests. We also evaluated the level of agreement between ELISAs and indirect haemagglutination (IHA) tests. The readings of the IC test results showed 100% agreement (POA = 1). The IC test on whole blood showed the following values: S = 87.3%; Sp = 98.8%; PPV = 96.9% and NPV = 95.9%. Additionally, the IC test on serum displayed the following results: S = 95.7%; Sp = 100%; PPV = 100% and NPV = 98.2%. Using whole blood, the agreement with ELISA was 96.3% and the agreement with IHA was 94.1%. Using serum, the agreement with ELISA was 97.8% and the agreement with IHA was 96.6%. The IC test performance with serum samples was excellent and demonstrated its usefulness in a PHCC with minimal equipment. If the IC test S value and NPV with whole blood are improved, then this test could also be used in areas lacking laboratories or specialised personnel.

Perspectiva interdisciplinaria para el abordaje de una enfermedad infecciosa: chagas o tripanosomiasis americana / Interdisciplinary perspective to approach an infectious disease: american trypanosomiasis or chagas disease

La enfermedad de Chagas, producida por elTrypanosomacruziy transmitida por un insecto triatomino, es de grancomplejidad. En el control de esta endemia no puedeconsiderarse la enfermedad como un hecho individualy sólo biológico. Entre sus múltiples componentes debeconsiderarse la relación de los sujetos con el hábitat, losmodos de producción, las condiciones culturales, lasrelaciones sociales y las formas organizativas.Como profesionales del campo de la salud intentamosnuevos enfoques que integran diferentes miradas disciplinaresy modos de intervención distintos, donde “el otro” recuperesu ser sujeto y no esté convocado a desempeñar un merorol de paciente. Posiciones que implican favorecer procesosparticipativos, escuchar a los propios protagonistas (mujerescon Chagas, equipos de salud, referentes comunitarios)recuperar sus peculiares visiones, poner en palabras lo nodicho sobre esta enfermedad silenciosa y silenciada, y develarlo que el Chagas esconde. Constituye una herramientaimportante a la hora de pensar propuestas de trabajo.

Chagas disease, caused by Trypanosoma cruzi and transmitted by a triatomine insectis extremely complicated. When controlling this endemic disease, the disease cannot beconsidered as an individual and merely biological fact. Among its many components therelationship of individuals to the habitat, production modes, cultural conditions, socialrelationships and organizational forms must be considered.As health professionals we present new approaches that integrate different disciplinesand modes of intervention, where “the other” recovers his/her individual being and isnot merely called upon to play a role as a patient. Positions that encourage participativeprocesses involving listening to the protagonists themselves (women with Chagas, healthteams, community references), recovering their unique visions, communicating what isnot said about this silent and hushed up disease, and revealing what Chagas hides areimportant tools when thinking about work proposals.

Epidemiología de la enfermedad de Chagas en menores en riesgo de la provincia de Santa Fe / Epidemiology of Chagas disease in children at risk in Santa Fe province

INTRODUCCION: El Chagas es una endemia prevalente en áreas rurales latinoamericanas por la persistencia del vector. El tratamiento etiológico es más efectivo en el período agudo (oligosintomático) y en menores de 15 años en cualquier etapa. En la provincia de Santa Fe, los departamentos 9 de Julio y Vera presentan un alto riesgo de transmisión por la presencia de vinchucas, con mayor peligro en las zonas rurales. En la periferia de la ciudad de Santa Fe (departamento La Capital) podría haber menores infectados por antecedentes migratorios.OBJETIVO: Diagnosticar niños de 1 a 15 años que residen en zona de riesgo o con antecedente migratorio, estimar probables vías de infección y comparar la prevalencia con trabajos anteriores.METODOS: Se realizó un estudio seroepidemiológico en escuelas de los distritos Garabato y Fortín Olmos (Vera), Gato Colorado (9 de Julio) y en la escuela ComCaia de Recreo (La Capital). A los seropositivos se les realizó una encuesta para determinar las probables vías de infección. Se comparó la prevalencia actual con la del último control de cada distrito.RESULTADOS: No se hallaron seropositivos en Recreo (prevalencia 0%, 0/130). La prevalencia fue de 1% (6/604) en Garabato; 1,88% (13/688) en Fortín Olmos y 3% (12/399) en Gato Colorado. Esto significó una disminución con respecto al último estudio: Garabato 11,2% (año 2000), Fortín Olmos 14,6% (2004), Gato Colorado 6,3% (2006). La vía de infección más frecuente sería la congénita, seguida por la vectorial.CONCLUSIONES: Pese a que la prevalencia disminuyó, se deben continuar las acciones de control tanto para la vía vectorial como para la congénita.

INTRODUCTION: Chagas is an endemic disease prevalent in Latin American rural areas due to the persistence of the vector. Eiological treatment is more effective un acute phase (oligosymptomatic) and in people younger than 15 years in any stage. In Santa Fe province, 9 de Julio and Vera departments are at high risk of transmission by the presence of triatomines, with greater risk in rural areas. On the outskirts of Santa Fe city (La Capital department) , there may be infected children due to migration background.OBJECTIVE: To diagnose children aged 1 to 15 years living in a risk area or with migrant background, to estimate the most probable way/s of infection and to compare the prevalence with previous works.METHODS: A seroepidemiological study was conducted in schools of the districts Garabato and Fortín Olmos (Vera), Gato Colorado (9 de Julio) and the school ComCaia in Recreo (La Capital). A survey was conducted in positive patients to determine the most probable way of infection. The current prevalence was compared with the last control in each district.RESULTS: No seropositives were found in Recreo (prevalence 0%, 0/130). The prevalence was 1% (6/694) in Garabato; 1.88% (13/688) in Fortín Olmos, and 3% (12/399) in Gato Colorado. This meant a decrease compared to the previous studies: Garabato 11.2% (2000), Fortín Olmos 14.6% (2004), Gato Colorado 6.3% (2006). The most probable way of infection was the congenital, followed by the vector one.CONCLUSIONS: Although the prevalence decreased, it is necessary to continue with these actions to prevent both vector and congenital transmission.

Perspectiva interdisciplinaria para el abordaje de una enfermedad infecciosa: chagas o tripanosomiasis americana / Interdisciplinary perspective to approach an infectious disease: american trypanosomiasis or chagas disease

La enfermedad de Chagas, producida por elTrypanosomacruziy transmitida por un insecto triatomino, es de grancomplejidad. En el control de esta endemia no puedeconsiderarse la enfermedad como un hecho individualy sólo biológico. Entre sus múltiples componentes debeconsiderarse la relación de los sujetos con el hábitat, losmodos de producción, las condiciones culturales, lasrelaciones sociales y las formas organizativas.Como profesionales del campo de la salud intentamosnuevos enfoques que integran diferentes miradas disciplinaresy modos de intervención distintos, donde ôel otroö recuperesu ser sujeto y no esté convocado a desempeñar un merorol de paciente. Posiciones que implican favorecer procesosparticipativos, escuchar a los propios protagonistas (mujerescon Chagas, equipos de salud, referentes comunitarios)recuperar sus peculiares visiones, poner en palabras lo nodicho sobre esta enfermedad silenciosa y silenciada, y develarlo que el Chagas esconde. Constituye una herramientaimportante a la hora de pensar propuestas de trabajo.(AU)

Chagas disease, caused by Trypanosoma cruzi and transmitted by a triatomine insectis extremely complicated. When controlling this endemic disease, the disease cannot beconsidered as an individual and merely biological fact. Among its many components therelationship of individuals to the habitat, production modes, cultural conditions, socialrelationships and organizational forms must be considered.As health professionals we present new approaches that integrate different disciplinesand modes of intervention, where ôthe otherö recovers his/her individual being and isnot merely called upon to play a role as a patient. Positions that encourage participativeprocesses involving listening to the protagonists themselves (women with Chagas, healthteams, community references), recovering their unique visions, communicating what isnot said about this silent and hushed up disease, and revealing what Chagas hides areimportant tools when thinking about work proposals.(AU)

Epidemiología de la enfermedad de Chagas en menores en riesgo de la provincia de Santa Fe / Epidemiology of Chagas disease in children at risk in Santa Fe province

INTRODUCCION: El Chagas es una endemia prevalente en áreas rurales latinoamericanas por la persistencia del vector. El tratamiento etiológico es más efectivo en el período agudo (oligosintomático) y en menores de 15 años en cualquier etapa. En la provincia de Santa Fe, los departamentos 9 de Julio y Vera presentan un alto riesgo de transmisión por la presencia de vinchucas, con mayor peligro en las zonas rurales. En la periferia de la ciudad de Santa Fe (departamento La Capital) podría haber menores infectados por antecedentes migratorios.OBJETIVO: Diagnosticar niños de 1 a 15 años que residen en zona de riesgo o con antecedente migratorio, estimar probables vías de infección y comparar la prevalencia con trabajos anteriores.METODOS: Se realizó un estudio seroepidemiológico en escuelas de los distritos Garabato y Fortín Olmos (Vera), Gato Colorado (9 de Julio) y en la escuela ComCaia de Recreo (La Capital). A los seropositivos se les realizó una encuesta para determinar las probables vías de infección. Se comparó la prevalencia actual con la del último control de cada distrito.RESULTADOS: No se hallaron seropositivos en Recreo (prevalencia 0%, 0/130). La prevalencia fue de 1% (6/604) en Garabato; 1,88% (13/688) en Fortín Olmos y 3% (12/399) en Gato Colorado. Esto significó una disminución con respecto al último estudio: Garabato 11,2% (año 2000), Fortín Olmos 14,6% (2004), Gato Colorado 6,3% (2006). La vía de infección más frecuente sería la congénita, seguida por la vectorial.CONCLUSIONES: Pese a que la prevalencia disminuyó, se deben continuar las acciones de control tanto para la vía vectorial como para la congénita.

INTRODUCTION: Chagas is an endemic disease prevalent in Latin American rural areas due to the persistence of the vector. Eiological treatment is more effective un acute phase (oligosymptomatic) and in people younger than 15 years in any stage. In Santa Fe province, 9 de Julio and Vera departments are at high risk of transmission by the presence of triatomines, with greater risk in rural areas. On the outskirts of Santa Fe city (La Capital department) , there may be infected children due to migration background.OBJECTIVE: To diagnose children aged 1 to 15 years living in a risk area or with migrant background, to estimate the most probable way/s of infection and to compare the prevalence with previous works.METHODS: A seroepidemiological study was conducted in schools of the districts Garabato and Fortín Olmos (Vera), Gato Colorado (9 de Julio) and the school ComCaia in Recreo (La Capital). A survey was conducted in positive patients to determine the most probable way of infection. The current prevalence was compared with the last control in each district.RESULTS: No seropositives were found in Recreo (prevalence 0%, 0/130). The prevalence was 1% (6/694) in Garabato; 1.88% (13/688) in Fortín Olmos, and 3% (12/399) in Gato Colorado. This meant a decrease compared to the previous studies: Garabato 11.2% (2000), Fortín Olmos 14.6% (2004), Gato Colorado 6.3% (2006). The most probable way of infection was the congenital, followed by the vector one.CONCLUSIONS: Although the prevalence decreased, it is necessary to continue with these actions to prevent both vector and congenital transmission.