Course of serological tests in treated subjects with chronic Trypanosoma cruzi infection: A systematic review and meta-analysis of individual participant data.

OBJECTIVE: To determine the course of serological tests in subjects with chronic Trypanosoma cruzi infection treated with anti-trypanosomal drugs. METHODS: A systematic review and meta-analysis was conducted using individual participant data. Survival analysis and the Cox proportional hazards regression model with random effects to adjust for covariates were applied. The protocol was registered in the PROSPERO database (http://www.crd.york.ac.uk/PROSPERO; CRD42012002162). RESULTS: A total of 27 studies (1296 subjects) conducted in eight countries were included. The risk of bias was low for all domains in 17 studies (63.0%). Nine hundred and thirteen subjects were assessed (149 seroreversion events, 83.7% censored data) for enzyme-linked immunosorbent assay (ELISA), 670 subjects (134 events, 80.0% censored) for indirect immunofluorescence assay (IIF), and 548 subjects (99 events, 82.0% censored) for indirect hemagglutination assay (IHA). A higher probability of seroreversion was observed within a shorter time span in subjects aged 1-19 years compared to adults. The chance of seroreversion also varied according to the country where the infection might have been acquired. For instance, the pooled adjusted hazard ratio between children/adolescents and adults for the IIF test was 1.54 (95% confidence interval 0.64-3.71) for certain countries of South America (Argentina, Bolivia, Chile, and Paraguay) and 9.37 (95% confidence interval 3.44-25.50) for Brazil. CONCLUSIONS: The disappearance of anti-T. cruzi antibodies was demonstrated along the course of follow-up. An interaction between age at treatment and country setting was found.

Prevalencia de infección por Trypanosoma cruzi en escolares de Salta y Chaco, Argentina / Seroprevalencia of Trypanosoma cruzi infection in school-age children from localities in Salta and Chaco, Argentina / Prevalência de infecção por Trypanosoma cruzi em crianças em idade escolar de Salta e Chaco, na Argentina

El objetivo del trabajo consistió en identificar la seroprevalencia de la infección por Trypanosoma cruzi en niños en edad escolar en localidades de las provincias de Salta y Chaco. Se trabajó en 44 escuelas de la ciudad de Salta, en parajes de San Carlos; en 10 escuelas de La Unión y en 7 escuelas de Taco Pozo. El trabajo tiene un diseño de corte transversal. La toma de muestra se realizó por punción capilar con equipos Serokit, y la confirmación de los casos seropositivos o dudosos por punción venosa, y obtención de suero, para realizar HAI y ELISA. Los casos seropositivos confirmados fueron tratados con Benznidazol® durante 60 días en dosis de 5-7mg/kg/ día. Para el análisis estadístico se elaboraron tablas con frecuencias absolutas y relativas. Se analizaron 17.884 escolares y se detectaron159 seropositivos, siendo la mayor seroprevalencia en la localidad de La Unión y la menor en la ciudad de Salta. Se aplicó tratamiento a 93 niños (71,54 %) de la ciudad y en el ámbito rural se trataron todos los casos. La vía de infección vectorial fue la de mayor predominio en las madres (64,47%). Se concluye que aunque la seroprevalencia fue menor en la ciudad de Salta que en las zonas rurales, es necesario continuar con la vigilancia.

The aim of this work was to identify seroprevalence of Trypanosoma cruzi infection in school-age children who live in localities from Salta and Chaco. This work was conducted in the following schools: 44 located in Salta city, 10 in La Unión, 7 in Taco Pozo, and several in rural spots around San Carlos town. The design was cross-sectional and the samples were taken by capillary punction with Serokit equipment. Seropositive cases were confirmed by HAI and ELISA performed on serum obtained by venous punction. Confirmed seropositive cases were treated with Benznidazol® for 60 days in doses of 5-7 mg/kg/day. Tables with absolute and relative frequencies were made for statistical analysis. It resulted that the number of school-aged children analyzed was 17,884, 159 being seropositive. The highest seroprevalence was detected in La Unión and the lowest in Salta city. Treatment was given to 93 children (71.54%) from Salta city, while every child was treated in rural areas. Infections in mothers was vector-borne mainly (64.47%). It can be concluded that even though seroprevalence was lower in the city of Salta than in rural areas, it is important to continue monitoring for Chagas disease.

O objetivo do trabalho consistiu em identificar a soroprevalência da infecção por Trypanosoma cruzi em crianças em idade escolar em localidades das províncias de Salta e de Chaco. O trabalho foi realizado em 44 escolas da cidade de Salta, em paragens de San Carlos; em 10 escolas de La Unión e em 7 escolas de Taco Pozo. O mesmo tem um desenho de corte transversal. Tomada de amostra: foi realizada por punção capilar com equipamentos Serokit e a confirmação dos casos soropositivos ou duvidoso por punção venosa e obtenção de soro, para realizar HAI e ELISA. Os casos soropositivos confirmados foram tratados com Benznidazole® durante 60 dias em doses de 5-7 mg/kg/dia. Para a análise estatística foram preparadas tabelas com frequências absolutas e relativas. Analisaram-se 17.884 crianças detectando 159 soropositivos, sendo a maior soroprevalência na cidade de La Unión e a menor na cidade de Salta. Aplicou-se o tratamento a 93 crianças, (71,54%) da cidade e na área rural se trataram todos os casos. A via de infecção vetorial foi a de maior predominância nas mães (64,47%). Conclui-se que embora a soroprevalência tenha sido menor na cidade de Salta do que nas áreas rurais, é necessário continuar com a vigilância.

Uso de la reacción en cadena de la polimerasa para el control terapéutico de la infección crónica por trypanosoma cruzi / Use of the polymerase chain reaction (pcr) for the therapeutic control of chronic trypanosoma cruzi infection

En las normas actuales de tratamiento etiológico de la fase crónica tardía de la enfermedad de Chagasen Argentina, Brasil y la Organización Mundial de la Salud, se recomienda controlar la eficaciaterapéutica con pruebas serológicas y parasitológicas convencionales. Sin embargo las primerassuelen continuar positivas 10 años o más luego del tratamiento, y las segundas son, en general, debaja sensibilidad en esta etapa de la enfermedad. La Reacción en Cadena de la Polimerasa (PCR)al ser más sensible que los exámenes parasitológicos convencionales, podría informar con unacobertura mayor si hubo falla terapéutica. Hemos ofrecido tratamiento con benznidazol (5 mg/kg/día, por 60 días) a 138 pacientes de 16 a 35 años de edad, infectados crónicamente con Trypanosomacruzi. La eficacia terapéutica se controló con PCR periódicas, hemocultivo y serología convencionalen dos grupos de pacientes: uno (GT, 57 pacientes) que aceptó y cumplió el tratamiento y otro(GNT, 37 pacientes) que lo rechazó. Antes de la administración de benznidazol la PCR mostró unasensibilidad diagnóstica de 41 por ciento (57/138 pacientes) y el hemocultivo 7,2 por ciento (10/138). Sesenta mesespostratamiento el grupo GT mostró una positividad de PCR acumulada de 28,1 por ciento (16/57) y el grupoGNT 54,1 por ciento (20/37; p=0.0016). A pesar de que la sensibilidad diagnóstica de PCR es limitada, lanegatividad de pruebas repetidas con método normatizado podría evidenciar disminución de laparasitemia o probable curación en 71,9 por ciento de los pacientes tratados, lo que habría que confirmar conel seguimiento serológico...

Current norms for the etiological treatment of chronic Chagas disease, recommended by WHOor currently in force for Argentina and Brazil, advise the control of therapeutic efficacy usingconventional serological and parasitological tests. However, serology usually remains positive 10 ormore years after treatment and parasitological tests are insensitive in the chronic stage. PolymeraseChain Reaction (PCR) is more sensitive than parasitological tests and could provide earlier evidenceof therapeutic failure. We offered benznidazole treatment (5 mg/kg/day, 60 days) to 138 patients(age=16 to 35 years old), chronically infected with Trypanosoma cruzi. Therapeutic efficacy waschecked with periodic PCR, haemoculture and conventional serology in two groups of patients: One(TG) accepting and complying with treatment and the other (NTG) rejecting it. Before benznidazoleadministration, PCR displayed a diagnostic sensitivity of 41.3 percent (57/138) and haemoculture 7.2 percent(10/138). Sixty months after treatment, TG displayed a cumulated PCR positivity of 28.1 percent (16/57)and NTG 54.1 percent (20/37; p=0.0166). Even though the sensitivity of PCR is limited, repeated negativeresults of a standardized method may reveal lower parasitaemia or probable cure, in 71.9 percent of treatedpatients, to be confirmed with serological follow up...

Diagnóstico de infección por Trypanosoma cruzi en Centros de Atención Primaria de Salta, Argentina / Diagnosis of Trypanosoma cruzi infection in Primary Public Health Centers of Salta, Argentina / Diagnóstico de infecþÒo por Trypanosoma cruzi nos Postos de Saúde de Salta, Argentina

La Enfermedad de Chagas causada por el parásito hemoflagelado Trypanosoma cruzi, constituye un grave problema de Salud Pública. En Argentina, se controla sistemáticamente la sangre a transfundir, la donación de órganos y se ha disminuido notablemente la transmisión vectorial. El objetivo de este proyecto fue implementar el uso del equipo para recolección de sangre capilar y conservación en glicerina (Serokit) en los servicios de enfermería de los Centros de Atención Primaria de la Salud en la ciudad de Salta a fin de conocer la seroprevalencia de infección por Trypanosoma cruzi en pacientes que concurren a los mismos. Para ello se realizó el par serológico HAI y ELISA en las muestras conservadas en Serokit y luego en muestras de sangre tomadas por punción venosa para confirmación. Durante dos años de trabajo se analizaron 1647 pacientes que concurrieron a 28 Centros de Salud, resultando 1,7% (29/1647) seropositivos. El Valor Predictivo Positivo fue 93,50% y el Valor Predictivo Negativo fue 99,8%. Todos los niños seropositivos fueron tratados con Benznidazol. Se concluye que el uso de Serokit para la toma y conservación de muestras para posterior diagnóstico de infección por Trypanosoma cruzi es recomendable en Centros de Atención Primaria de la Salud que no cuentan con laboratorio.(AU)

Chagas disease is caused by the hemoflagelate parasite Trypanosoma cruzi, and represents a main concern in public health. In Argentina, blood transfusion and organ donation are systematically controlled for T. cruzi infection, and vectorial transmission has dropped significantly. The aim of this project was to implement the use of the equipment for collecting capillary blood and conservation in glycerine (Serokit) in the nursery service of Primary Health Care Centers (PHCC) in the city of Salta, and to know the seroprevalence of T. cruzi infection in PHCC patients. To that aim, the serological pair HAI and ELISA was carried out in samples preserved in Serokit, followed by analysis of blood samples taken by venous punction to confirm the results. During a two-year period, 1647 patients that were assisted at 28 PCHC were analyzed, resulting in 1.7% (29/1647) seropositive samples. Positive Predictive Value was 93.5% and Negative Predictive Value was 99.8%. Every seropositive child was given Benznidazole treatment. It can be concluded that use of Serokit for taking and preserving samples to diagnose serologically T. cruzi infection is recommended in PHCC that lack their own biochemistry laboratory.(AU)

A doenþa de Chagas produzida pelo protozoário flagelado Trypanosoma cruzi constitui um grave problema para a Saúde Pública. Na Argentina, o controle sistemático do sangue para transfusÒo e o do órgÒo para transplantar, fez com que diminuísse notavelmente a transmissÒo vetorial. O objetivo deste projeto foi implementar o uso do equipamento para coleta de sangue capilar e conservaþÒo em glicerina (Serokit) nos serviþos de enfermagem dos Postos de AtenþÒo Primaria da Saúde da cidade de Salta a fim de conhecer a soroprevalÛncia de infecþÒo com Trypanosoma cruzi em pacientes que sÒo atendidos nos mesmos. Foi realizado o par sorológico HAI e ELISA nas amostras conservadas em Serokit e depois nas amostras de sangue retiradas através de uma punþÒo venosa para a confirmaþÒo. Durante dois anos de trabalho, foram analisados 1647 pacientes que foram atendidos nos 28 Postos de Saúde, resultando 1.7% (29/1647) soropositivos. O Valor Preditivo Positivo foi Tripae 93.50% e o Valor Preditivo Negativo foi de 99.8%. Todas as crianþas soropositivas foram medicadas com Benznidazol. A conclusÒo é que o uso de Serokit para a tomada e conservaþÒo de amostras para posterior diagnóstico de infecþÒo por Trypanosoma cruzi é recomendável nos Postos de AtenþÒo Primária da Saúde onde nÒo existe a disponibilidade de laboratórios.(AU)

Diagnóstico de infección por Trypanosoma cruzi en Centros de Atención Primaria de Salta, Argentina / Diagnosis of Trypanosoma cruzi infection in Primary Public Health Centers of Salta, Argentina / Diagnóstico de infecção por Trypanosoma cruzi nos Postos de Saúde de Salta, Argentina

La Enfermedad de Chagas causada por el parásito hemoflagelado Trypanosoma cruzi, constituye un grave problema de Salud Pública. En Argentina, se controla sistemáticamente la sangre a transfundir, la donación de órganos y se ha disminuido notablemente la transmisión vectorial. El objetivo de este proyecto fue implementar el uso del equipo para recolección de sangre capilar y conservación en glicerina (Serokit) en los servicios de enfermería de los Centros de Atención Primaria de la Salud en la ciudad de Salta a fin de conocer la seroprevalencia de infección por Trypanosoma cruzi en pacientes que concurren a los mismos. Para ello se realizó el par serológico HAI y ELISA en las muestras conservadas en Serokit y luego en muestras de sangre tomadas por punción venosa para confirmación. Durante dos años de trabajo se analizaron 1647 pacientes que concurrieron a 28 Centros de Salud, resultando 1,7% (29/1647) seropositivos. El Valor Predictivo Positivo fue 93,50% y el Valor Predictivo Negativo fue 99,8%. Todos los niños seropositivos fueron tratados con Benznidazol. Se concluye que el uso de Serokit para la toma y conservación de muestras para posterior diagnóstico de infección por Trypanosoma cruzi es recomendable en Centros de Atención Primaria de la Salud que no cuentan con laboratorio.

Chagas disease is caused by the hemoflagelate parasite Trypanosoma cruzi, and represents a main concern in public health. In Argentina, blood transfusion and organ donation are systematically controlled for T. cruzi infection, and vectorial transmission has dropped significantly. The aim of this project was to implement the use of the equipment for collecting capillary blood and conservation in glycerine (Serokit) in the nursery service of Primary Health Care Centers (PHCC) in the city of Salta, and to know the seroprevalence of T. cruzi infection in PHCC patients. To that aim, the serological pair HAI and ELISA was carried out in samples preserved in Serokit, followed by analysis of blood samples taken by venous punction to confirm the results. During a two-year period, 1647 patients that were assisted at 28 PCHC were analyzed, resulting in 1.7% (29/1647) seropositive samples. Positive Predictive Value was 93.5% and Negative Predictive Value was 99.8%. Every seropositive child was given Benznidazole treatment. It can be concluded that use of Serokit for taking and preserving samples to diagnose serologically T. cruzi infection is recommended in PHCC that lack their own biochemistry laboratory.

A doença de Chagas produzida pelo protozoário flagelado Trypanosoma cruzi constitui um grave problema para a Saúde Pública. Na Argentina, o controle sistemático do sangue para transfusão e o do órgão para transplantar, fez com que diminuísse notavelmente a transmissão vetorial. O objetivo deste projeto foi implementar o uso do equipamento para coleta de sangue capilar e conservação em glicerina (Serokit) nos serviços de enfermagem dos Postos de Atenção Primaria da Saúde da cidade de Salta a fim de conhecer a soroprevalência de infecção com Trypanosoma cruzi em pacientes que são atendidos nos mesmos. Foi realizado o par sorológico HAI e ELISA nas amostras conservadas em Serokit e depois nas amostras de sangue retiradas através de uma punção venosa para a confirmação. Durante dois anos de trabalho, foram analisados 1647 pacientes que foram atendidos nos 28 Postos de Saúde, resultando 1.7% (29/1647) soropositivos. O Valor Preditivo Positivo foi Tripae 93.50% e o Valor Preditivo Negativo foi de 99.8%. Todas as crianças soropositivas foram medicadas com Benznidazol. A conclusão é que o uso de Serokit para a tomada e conservação de amostras para posterior diagnóstico de infecção por Trypanosoma cruzi é recomendável nos Postos de Atenção Primária da Saúde onde não existe a disponibilidade de laboratórios.

Histologic and histomorphometric study of bone repair under acute Trypanosoma cruzi infection in rats.

Trypanosoma cruzi (T cruzi) is an intracellular protozoan pathogen that causes American trypanosomiasis (Chagas disease). The aim of this study was to evaluate the histopathological effects of acute infection by T. cruzi on bone repair, Wistar rats were used throughout. The animals were assigned to two groups: Control Group (CG n =20) and Experimental Group (EG n = 20). All the animals were anesthetized, at to the first lower right molar was extracted. The EG animals were inoculated subcutaneously at to with 0.1 mL of 10 trypomastigotes of the virulent strain Tulahuen of T. cruzi. The CG animals were administered an equivalent volume ofsaline solution subcutaneously. The animals in both groups were euthanized at 15 days post-infection and tooth extraction. The mandibles were resected, fixed informalin solution, radiographed, decalcified and embedded in paraffin. Bucco-lingually oriented sections were obtained at the level of the mesial tooth socket of the first lower molar and stained with hematoxylin-eosin. Total alveolar volume (TV) and bone volume (TBV/TV) in the apical third of the tooth socket were evaluated histomorphometrically. The histological analysis revealed an alteration in post-extraction bone tissue repair in animals infected by T. cruzi. A reduction in osteogenic activity was observed concomitant with a rise in quiescent and eroded bone surfaces. Histomorphometric evaluation revealed a significant reduction (19%) in total alveolar volume (TV) and bone volume (TBV/TV) (24%) in the apical third of the tooth socket in animals infected with T. cruzi in comparison to non-infected animals (p<0.05). The results obtained using this experimental model showed decreased osteogenesis in bone tissue repair under acute Trypanosoma cruzi infection in rats.

Detección, tratamiento y control de niños infectados con trypanosoma cruzi: estudio transversal en centros de atención primaria de Salta, Argentina / Detection, treatment and control of children infected with trypanosoma cruzi: cross-sectional study in centers of primary care of Salta, Argentina

INTRODUCCION: En la ciudad de Salta, la transmisión vectorial de la Enfermedad de Chagas se ha interrumpido desde 1970. Sin embargo, la transmisión congénita continúa debido a la presencia de mujeres infectadas en edad fértil.OBJETIVO: El estudio se propuso: a) incentivar la búsqueda de madres seropositivas, b) diagnosticar y tratar a los niños infectados, c) probar posibles marcadores precoces de curación a fin de evaluar en menor tiempo la efectividad del tratamiento.METODOS: Se trabajó en coordinación con Centro de Atención Primaria de la Salud de la ciudad de Salta. Se aplicaron métodos serológicos convencionales y no convencionales.RESULTADOS: La seroprevalencia en embarazadas en la ciudad de Salta en 2010 fue de 3,1% (61/1946). Se analizaron 57 niños y se encontraron 16 infectados con Trypanosoma cruzi, diagnosticados por microhematocrito o por serología convencional según la edad. Se aplicó tratamiento según las Normas Nacionales de Atención al Infectado Chagásico. Se evaluó la efectividad del tratamiento en 33 niños (edad promedio: 9,6 años), que habían sido tratados durante 2007-2008. El 21,2% (7/33) de esos niños fueron negativos por hemaglutinación en el postratamiento; además, se detectaron 3 antígenos recombinantes como posibles marcadores precoces de cura: Ag SAPA (p=0,0000182), Ag 13 (p=0,0026) y Ag 1 (p=0,02).CONCLUSIONES: Se recomienda el tratamiento y su seguimiento en todos los niños infectados.

INTRODUCTION: In the city of Salta, the vector transmission of Chagas disease has been interrupted since 1970. Nevertheless, congenital transmission is still a problem due to infected women in fertile age.OBJECTIVE: The aims of this study were: a) to search for seropositive mothers, b) to diagnose and to treat infected children, c) to test new antigens in order to detect early markers of treatment effectiveness.METHODS: The study was conducted in coordination with Centers of Primary Health Care in Salta. Conventional and non-conventional serological techniques were applied.RESULTS: During 2010, the Chagas disease prevalence in pregnant women was 3.1% (61/1946). Besides, 16 trypanosoma cruzi-infected children were found, out of 57 analyzed (diagnosed by microhematocrit or by conventional serology, depending on the age). Treatment was applied according to national care guidelines for Chagas disease infected patients. The efficiency of treatment was evaluated in 33 children (average: 9.6 years old), which had been treated during 2007-2008. From these, 21.2% (7/33) were negative for hemagglutination in the post-treatment; and 3 recombinant antigens were detected as possible good markers of treatment effectiveness: Ag SAPA (p=0.0000182), Ag 13 (p=0.0026) and Ag 1 (p=0.02).CONCLUSIONS: Treatment and follow-up should be performed in all infected children.

Detección, tratamiento y control de niños infectados con trypanosoma cruzi: estudio transversal en centros de atención primaria de Salta, Argentina / Detection, treatment and control of children infected with trypanosoma cruzi: cross-sectional study in centers of primary care of Salta, Argentina

INTRODUCCION: En la ciudad de Salta, la transmisión vectorial de la Enfermedad de Chagas se ha interrumpido desde 1970. Sin embargo, la transmisión congénita continúa debido a la presencia de mujeres infectadas en edad fértil.OBJETIVO: El estudio se propuso: a) incentivar la búsqueda de madres seropositivas, b) diagnosticar y tratar a los niños infectados, c) probar posibles marcadores precoces de curación a fin de evaluar en menor tiempo la efectividad del tratamiento.METODOS: Se trabajó en coordinación con Centro de Atención Primaria de la Salud de la ciudad de Salta. Se aplicaron métodos serológicos convencionales y no convencionales.RESULTADOS: La seroprevalencia en embarazadas en la ciudad de Salta en 2010 fue de 3,1% (61/1946). Se analizaron 57 niños y se encontraron 16 infectados con Trypanosoma cruzi, diagnosticados por microhematocrito o por serología convencional según la edad. Se aplicó tratamiento según las Normas Nacionales de Atención al Infectado Chagásico. Se evaluó la efectividad del tratamiento en 33 niños (edad promedio: 9,6 años), que habían sido tratados durante 2007-2008. El 21,2% (7/33) de esos niños fueron negativos por hemaglutinación en el postratamiento; además, se detectaron 3 antígenos recombinantes como posibles marcadores precoces de cura: Ag SAPA (p=0,0000182), Ag 13 (p=0,0026) y Ag 1 (p=0,02).CONCLUSIONES: Se recomienda el tratamiento y su seguimiento en todos los niños infectados.

INTRODUCTION: In the city of Salta, the vector transmission of Chagas disease has been interrupted since 1970. Nevertheless, congenital transmission is still a problem due to infected women in fertile age.OBJECTIVE: The aims of this study were: a) to search for seropositive mothers, b) to diagnose and to treat infected children, c) to test new antigens in order to detect early markers of treatment effectiveness.METHODS: The study was conducted in coordination with Centers of Primary Health Care in Salta. Conventional and non-conventional serological techniques were applied.RESULTS: During 2010, the Chagas disease prevalence in pregnant women was 3.1% (61/1946). Besides, 16 trypanosoma cruzi-infected children were found, out of 57 analyzed (diagnosed by microhematocrit or by conventional serology, depending on the age). Treatment was applied according to national care guidelines for Chagas disease infected patients. The efficiency of treatment was evaluated in 33 children (average: 9.6 years old), which had been treated during 2007-2008. From these, 21.2% (7/33) were negative for hemagglutination in the post-treatment; and 3 recombinant antigens were detected as possible good markers of treatment effectiveness: Ag SAPA (p=0.0000182), Ag 13 (p=0.0026) and Ag 1 (p=0.02).CONCLUSIONS: Treatment and follow-up should be performed in all infected children.

Histologic and histomorphometric study of bone repair under acute Trypanosoma cruzi infection in rats

Trypanosoma cruzi (T. cruzi) is an intracellular protozoan pathogen that causes American trypanosomiasis (Chagas disease). The aim of this study was to evaluate the histopathological effects of acute infection by T. cruzi on bone repair. Wistar rats were used throughout. The animals were assigned to two groups: Control Group (CG n =20) and Experimental Group (EG n =20). All the animals were anesthetized, at t0 the first lower right molar was extracted. The EG animals were inoculated subcutaneously at t0 with 0.1 mL of 105 trypomastigotes of the virulent strain Tulahuen of T. cruzi. The CG animals were administered an equivalent volume of saline solution subcutaneously. The animals in both groups were euthanized at 15 days post-infection and tooth extraction. The mandibles were resected, fixed in formalin solution, radiographed, decalcified and embedded in paraffin. Bucco-lingually oriented sections were obtained at the level of the mesial tooth socket of the first lower molar, and stained with hematoxylin-eosin. Total alveolar volume (TV) and bone volume (TBV/TV) in the apical third of the tooth socket were evaluated histomorphometrically. The histological analysis revealed an alteration in post-extraction bone tissue repair in animals infected by T. cruzi. A reduction in osteogenic activity was observed concomitant with a rise in quiescent and eroded bone surfaces. Histomorphometric evaluation revealed a significant reduction (19%) in total alveolar volume (TV) and bone volume (TBV/TV) (24%) in the apical third of the tooth socket in animals infected with T. cruzi in comparison to non-infected animals (p<0.05). The results obtained using this experimental model showed decreased osteogenesis in bone tissue repair under acute Trypanosoma cruzi infection in rats.

El Trypanosoma cruzi (T. cruzi) es un protozoario intracelular que causa Trypanosomoniasis Americana (Enfermedad de Chagas). El objetivo del presente trabajo fue el estudio histopatologico del efecto de la infeccion aguda por Trypanosoma cruzi sobre la reparacion del tejido oseo. Se utilizaron ratas Wistar macho que fueron asignadas a dos grupos: Grupo Control (GC n =20) y Grupo Experimental (GE n =20). Los animales de ambos grupos, bajo anestesia general intraperitoneal, fueron sometidos a t0, a exodoncia del primer molar inferior derecho, en el GE fueron inoculados,a t0 por via subcutanea en la region inguinal izquierda con 0.1 mL de 105 tripomastigotes de la cepa virulenta Tulahuen de Trypanosoma cruzi. A los animales del GC se les administro el volumen equivalente de solucion salina por via subcutanea. A los animales de ambos grupos se les practico la eutanasia a los 15 dias. Se resecaron las mandibulas, se fijaron en solucion de formol al 10%, se radiografiaron, se descalcificaron y se incluyeron en parafina. Se obtuvieron cortes orientados en sentido vestibulo-lingual a nivel del alveolo mesial del primer molar inferior derecho y se colorearon con hematoxilina-eosina para su posterior estudio histologico e histomorfometrico. Histologicamente se observo una menor actividad osteogenica a expensas de un incremento de las superficies quiescentes y de las superficies erosivas en el GE. En la evaluacion histomorfometrica se detecto disminucion estadiasticamente significativa del volumen oseo total (19%) y del volumen trabecular en el tercio apical del alveolo (24%) en el GE con respecto al GC (p<0.05). Los resultados obtenidos en este modelo experimental evidencian una disminucion de la osteogenesis en la reparacion osea en ratas con infeccion aguda por Trypanosoma cruzi.

Hydroxymethylnitrofurazone is active in a murine model of Chagas' disease.

The addition of a hydroxymethyl group to the antimicrobial drug nitrofurazone generated hydroxymethylnitrofurazone (NFOH), which had reduced toxicity when its activity against Trypanosoma cruzi was tested in a murine model of Chagas' disease. Four groups of 12 Swiss female mice each received 150 mg of body weight/kg/day of NFOH, 150 mg/kg/day of nitrofurazone (parental compound), 60 mg/kg/day of benznidazole (BZL), or the solvent as a placebo. Treatments were administered orally once a day 6 days a week until the completion of 60 doses. NFOH was as effective as BZL in keeping direct parasitemia at undetectable levels, and PCR results were negative. No histopathological lesions were seen 180 days after completion of the treatments, a time when the levels of anti-T. cruzi antibodies were very low in mice treated with either NFOH or BZL. Nitrofurazone was highly toxic, which led to an overall rate of mortality of 75% and necessitated interruption of the treatment. In contrast, the group treated with its hydroxymethyl derivative, NFOH, displayed the lowest mortality (16%), followed by the BZL (33%) and placebo (66%) groups. The findings of histopathological studies were consistent with these results, with the placebo group showing the most severe parasite infiltrates in skeletal muscle and heart tissue and the NFOH group showing the lowest. The present evidence suggests that NFOH is a promising anti-T. cruzi agent.

Serological evaluation of specific-antibody levels in patients treated for chronic Chagas' disease.

Serological tests are the main laboratory procedures used for diagnosis during the indeterminate and chronic stages of Chagas' disease. A serological regression to negativity is the main criterion used to define parasitological cure in treated patients. The aim of this work was to monitor the individual specificities of antibody levels for 3 years posttreatment in 18 adult patients. Conventional serological techniques (hemagglutination assays and enzyme-linked immunosorbent assay [ELISA]) were modified by using recombinant antigens to detect early markers of treatment effectiveness. For this purpose, serum samples were taken before and during treatment and every 6 months after treatment for at least 3 years. When hemagglutination assays were used, a decrease in antibody levels was observed in only one patient. When ELISA with serum dilutions was used, antibody clearance became much more apparent: in 77.7% (14/18) of the patients, antibody titers became negative with time. This was observed at serum dilutions of 1/320 and occurred between the 6th and the 30th months posttreatment. The immune response and the interval for a serological regression to negativity were different for each patient. For some of the recombinant antigens, only 50% (9/18) of the patients reached the serological regression to negativity. Recombinant antigen 13 might be a good marker of treatment effectiveness, since 66.6% (six of nine) of the patients presented with an early regression to negativity for specific antibodies to this antigen (P = 0.002).

High prevalence of congenital Trypanosoma cruzi infection and family clustering in Salta, Argentina.

OBJECTIVE: Trypanosoma cruzi, the causative agent of Chagas' disease, is transmitted mainly by insect vectors, but congenital and transfusion-borne infections occasionally occur. The factors that are involved in transmission from mother to offspring are not well understood. The objective of this study was to study the presence of T cruzi infection in children who were born to infected mothers and in the children's siblings to evaluate the epidemiologic risk factors associated with congenital transmission of Chagas' disease. METHODS: Congenital T cruzi infection was studied in 340 children who were born to chronically infected mothers in Salta, Argentina. Infection was detected in 31 children, who were selected for additional study as infected index cases (IIC). Of the 309 noninfected children, 31 were taken as noninfected index cases (NIIC). We compared the prevalence of congenital T cruzi transmission in the remaining siblings of the IIC and NIIC. Data and blood samples were collected in house-to-house visits. Diagnosis of infection was established mainly by serologic methods, indirect hemmagglutination, and enzyme-linked immunosorbent assay. RESULTS: The prevalence was 31.4% (32 of 102 children) for IIC siblings, whereas no infected siblings were found in families with NIIC (0 of 112). Clustering of congenital infection was found in 14 families, in which >1 child was infected. Second-generation congenital transmission (from grandmother to mother to newborn) was established in 4 families. The association among low weight at birth, prematurity, and congenital transmission was highly significant. An important observation was the absence of pathologic findings in a high proportion of infected children. The detection of asymptomatic infections was a consequence of population screening, as opposed to hospital-based diagnosis, for which symptomatic cases predominate. Congenital transmission was associated with the geographic origin of mothers: women from areas where insect vectors proliferate were less likely to give birth to infected offspring than women from areas under active vector control. CONCLUSIONS: Siblings of an infant infected with T cruzi are at high risk for infection themselves and, even in the absence of symptoms, should also be screened for infection. The findings of family clustering of infection and of second-generation congenital infection in vector-free areas suggest that new modalities of transmission, other than classic vector-borne spread, may occur both in endemic and in nonendemic areas.

Early diagnosis of congenital Trypanosoma cruzi infection using PCR, hemoculture, and capillary concentration, as compared with delayed serology.

Congenital Trypanosoma cruzi infection is a highly pathogenic and underreported condition. Early recognition is essential for effective treatment. Umbilical chord blood from newborns (n = 302) to infected mothers was analyzed with microhematocrit, hemoculture, and PCR methods. Each subject was then followed serologically. In calibrated suspensions of T. cruzi in blood, the sensitivity of PCR was 27-fold higher than hemoculture. However, this advantage was not reflected during routine testing of samples from maternities, partly because of the uneven distribution of few parasites in small samples. Levels of detection of congenital infection were 2.9% (8/272) for microhematocrit, 6.3% (18/287) for hemoculture, 6.4% (15/235) for PCR, and 8.9% (27/302) for cumulated results. Evaluation against the standard of delayed serology indicates that the regular application of PCR, hemoculture, and microhematocrit to blood samples allows the rapid detection of about 90% of the congenitally infected newborns, in samples that can be obtained before the mother and child leave the maternity ward.

Aporte de las técnicas de biología molecular al diagnóstico de la enfermedad de Chagas / Contribution of the molecular biology technics at Chaga's disease

El diagnóstico parasitológico en la Enfermedad de Chagas se ve dificultado por la escasez de parásitos en el material diagnóstico y por los inconvenientes que surgen al emplear las técnicas serológicas para descubrir casos agudos, casos de enfermedad congénita o bolsas de transfusión contaminadas. La Reacción en Cadena de Polimerasas (PCR) ha superado la sensibilidad de las técnicas convencionales de diagnóstico parasitológico porque no sólo es capaz de detectar indirectamente a los parásitos como unidad, sino también a segmentos específicos de ADN que están representados centenares de veces en cada parásito. Presentamos aquí las experiencias que hemos podido realizar hasta ahora para detectar al Trypanosoma cruzi en bolsas de transfusión y en sangre de neonatos de madres chagásicas. En 52 bolsas de transfusión analizadas por 2 métodos serológicos y por PCR encontramos que esta técnica (como así también el hemocultivo y el xerodiagnóstico) tiene poca concordancia (52 por ciento) con la serología. La técnica PCR confirmó 12 de 14 muestras seronegativas (85,7 por ciento es especificidad), pero sólo 15 de 38 seropositivas (39,5 por ciento), lo que indicaría que las pruebas serológicas no señalan, necesariamente, aquellas bolsas que contienen parásitos. La detección precoz del Trypanosoma cruzi en la sangre del recién nacido de madre chagásica es esencial para diagnosticar y tratar la Enfermedad de Chagas congénita, pero con frecuencia los métodos empleados fallan por falta de sensibilidad. Hemos aplicado la técnica PCR y el hemocultivo en forma sistemática a 34 hijos de madres chagásicas, detectando hasta ahora 2 casos congénitos que no habían sido diagnosticados por el método usual de microstrout. El alto costo del método PCR lo hace muy poco recomendable para el tamizaje de los bancos de sangre. Sin embargo, para el diagnóstico de Chagas congénito, esta técnica sería económicamente rentable si se usa como complemento de otros métodos en los centros de diagnóstico perinatal de las zonas endémicas.

Aporte de las técnicas de biología molecular al diagnóstico de la enfermedad de Chagas / Contribution of the molecular biology technics at Chagas disease

El diagnóstico parasitológico en la Enfermedad de Chagas se ve dificultado por la escasez de parásitos en el material diagnóstico y por los inconvenientes que surgen al emplear las técnicas serológicas para descubrir casos agudos, casos de enfermedad congénita o bolsas de transfusión contaminadas. La Reacción en Cadena de Polimerasas (PCR) ha superado la sensibilidad de las técnicas convencionales de diagnóstico parasitológico porque no sólo es capaz de detectar indirectamente a los parásitos como unidad, sino también a segmentos específicos de ADN que están representados centenares de veces en cada parásito. Presentamos aquí las experiencias que hemos podido realizar hasta ahora para detectar al Trypanosoma cruzi en bolsas de transfusión y en sangre de neonatos de madres chagásicas. En 52 bolsas de transfusión analizadas por 2 métodos serológicos y por PCR encontramos que esta técnica (como así también el hemocultivo y el xerodiagnóstico) tiene poca concordancia (52 por ciento) con la serología. La técnica PCR confirmó 12 de 14 muestras seronegativas (85,7 por ciento es especificidad), pero sólo 15 de 38 seropositivas (39,5 por ciento), lo que indicaría que las pruebas serológicas no señalan, necesariamente, aquellas bolsas que contienen parásitos. La detección precoz del Trypanosoma cruzi en la sangre del recién nacido de madre chagásica es esencial para diagnosticar y tratar la Enfermedad de Chagas congénita, pero con frecuencia los métodos empleados fallan por falta de sensibilidad. Hemos aplicado la técnica PCR y el hemocultivo en forma sistemática a 34 hijos de madres chagásicas, detectando hasta ahora 2 casos congénitos que no habían sido diagnosticados por el método usual de microstrout. El alto costo del método PCR lo hace muy poco recomendable para el tamizaje de los bancos de sangre. Sin embargo, para el diagnóstico de Chagas congénito, esta técnica sería económicamente rentable si se usa como complemento de otros métodos en los centros de diagnóstico perinatal de las zonas endémicas. (AU)