Ten-year follow-up of the largest oral Chagas disease outbreak. Laboratory biomarkers of infection as indicators of therapeutic failure.

Trypanosoma cruzi uses various mechanisms of infection to access humans. Since 1967, food contaminated with metacyclic trypomastigotes has triggered several outbreaks of acute infection of Chagas disease by oral transmission. Follow-up studies to assess the effectiveness of anti-parasitic treatment of oral outbreaks are rather scarce. Here, we report a 10-year laboratory follow-up using parasitological, serological, and molecular tests of 106 individuals infected in 2007 of the largest known outbreak of orally transmitted Chagas disease, which occurred in Caracas city, Venezuela. Before treatment (2007), specific IgA, IgM and IgG, were found in 71% (75/106), 90% (95/106) and 100% (106/106), respectively, in addition to 21% (9/43) parasitemia, Complement Mediated Lysis (CML) in 98% (104/106) and 79% (34/43) parasitic DNA for PCR. Blood culture detected parasitemia up to 18 months post-treatment in 6% (6/106) of the patients. In 2017, the original number of cases in the follow-up decreased by 46% and due to the country's economic situation, not all the trials could be carried out in the entire population. During follow-up, IgA and IgM disappeared promptly, with IgM persisting in 19% (20/104) of the patients three years after treatment. The anti-T. cruzi IgG remained positive 10 years later in 41% (20/49) of the individuals evaluated. CML remained positive seven years later in 79% (65/82) of the cases. PCR positive cases decreased after treatment but progressively recovered, being positive in 69% (32/46) of the individuals evaluated in 2017. The group of children (under 18 years of age) showed the highest PCR positivity with 76% (26/34) of the cases, but their parasitic load tended to diminish, while in adults the parasitic load regained their initial values. The simultaneous evaluation of serological tests and PCR of the patients allowed us to separate patients among responders and non-responders to the anti-parasitic treatment, and this information prompted us to apply a second anti-parasitic treatment in the group of non-responders. In this population not subjected to the like lihood of re-infection, adult patients were more likely to be non-responders when compared to children. These results suggest that rigorous laboratory follow-up with T. cruzi infectious biomarkers is essential to detect cases of parasite persistence.

Enfermedad de Chagas y el binomio madre-hijo / Chagas disease and the mother-son binomy

La infección por Trypanosoma cruzi está garantizada por la presencia del parásito en muchos géneros animales incluido el hombre. Este a su vez, no solo adquiere el parásitoa través del vector (cutánea, por mucosas, oral) o por secreciones de didelfidos o accidentalmente por manipulación de material biológico infectante,sino también por la trasmisión hombre-hombre la cual aumenta la diseminación de la Enfermedad de Chagas aunque en menor proporción (trasmisión congénita, transfusional o por trasplante de tejidos). El parásito alcanza al feto in utero principalmente por su capacidad de atravesar la placenta especialmente después de la semana 20 cuando la barrera placentaria se adelgaza progresivamente. Sin embargo solo del 1 al 10% de los niños nacidos de madres con Enfermedad de Chagas desarrollan infección aguda variando de acuerdo al país, edad gestacional, al genotipo y carga del parásito entre varios factores. La clínica del neonato con T. cruzi va desde casos asintomáticos, bajo peso, prematuridad, hepatoesplenomegalia, dificultad respiratoria,hastael desenlace fatal. La prevención se basa en la detección por serología y tratamiento oportuno en niñas y mujeres antes del embarazo ya que los antiparasitarios específicos producen efectos adversos y en principio están contraindicados durante el embarazo. En cambio el tratamiento está indicado en el niño en cualquier momento cuando se demuestre la patología. El despistaje de la infección por T. cruzi debería ser obligatorio en toda Latinoamérica y en toda mujer latinoamericana en el mundo a fin de estar preparado para la atención postparto al infante y a la madre(AU)

Infection with Trypanosoma cruzi is guaranteed by the presence of the parasite in many animal genera including man. This in turn, not only acquires the parasite by contact with a vector (skin, mucoses and oral transmission) or by secretions of didelfides or accidentally by manipulation of infecting biological material, but also by man-man transmission which increases the spread of Chagas disease (congenital, transfusion or tissue transplant transmission). The parasite reaches the fetus in utero mainly due to its ability to cross the placenta especially after week 20 when the placental barrier becomes progressively thinner. However, only 1 to 10% of children born from mothers with Chagas disease develop acute infection, varying according to country, gestational age, genotype, and parasite load among various factors. The clinic of the neonate with T. cruzi ranges from asymptomatic cases, low weight, prematurity, hepatosplenomegaly, respiratory distress to the fatal outcome. Prevention is based on the detection by serology and timely treatment in girls and women before pregnancy since specific antiparasitic drugs produce adverse effects and are in principle contraindicated during pregnancy. Instead, treatment is indicated in the child at any time when the pathology is demonstrated. The screening of T. cruzi infection should be mandatory in all Latin America and in all Latin American women in the world in order to be prepared for the postpartum care of the infant and the mother(AU)

Toxoplasmosis y Enfermedad de Chagas: seroprevalencia y factores de riesgo en embarazadas del HUC

La Toxoplasmosis y la Enfermedad de Chagas (ECh) son infecciones parasitarias frecuentes en Latinoamérica, capaces de ser transmitidas verticalmente durante el embarazo. Este trabajo tiene como objetivo determinar la seroprevalencia ante Trypanosoma cruzi (T. cruzi) y Toxoplasma gondii (T. gondii), en las embarazadas de la consulta prenatal del Ambulatorio Docente del Hospital Universitario de Caracas. Estudio analítico, prospectivo de corte transversal, realizado en 300 pacientes, en el lapso comprendido entre enero 2018 ­ marzo 2019. El 31,66 % de la población estudiada presentó seropositividad para anticuerpos IgG específicos para T. gondii, avidez de IgG mayor al 50 % e IgM negativa en todas, resultados compatibles con la fase crónica de la infección. Al correlacionar con los factores de riesgo habituales para la transmisión de T. gondii destacaron el contacto con heces de gato (46,3 %) y el consumo de agua directamente del grifo (32,6 %). En el caso de la ECh se demostró la presencia de factores de riesgo en la población estudiada, como contacto con triatominos (51,45 %) y viviendas cercanas a vegetación (49 %), sin embargo, solo una embarazada (0,33 %) demostró seropositividad para T. cruzi sin presentar relación con los factores de riesgo estudiados. Se evidenció una seroprevalencia muy frecuente para T. gondii y menor para T. cruzi, con factores de riesgo para la trasmisión vectorial cutánea y oral muy altos, constituyéndo una amenaza tanto para la embarazada como para al feto. Se recomienda educar a la población para reducir su exposición a factores de riesgo.

Toxoplasmosis and Chagas Disease (ChD) are frequent parasitic infections in Latin America, capables of vertical transmission during pregnancy. The purpose of this article is to determine the seroprevalence against Trypanosoma cruzi (T. cruzi) and Toxoplasma gondii (T. gondii), in pregnant women attending the prenatal clinic of the "Hospital Universitario de Caracas". Analytical, prospective study of a transversal cohort, carried out in 300 patients, during the period January 2018 - March 2019. The 31.66 % of the analyzed population showed seropositivity for IgG specific antibodies for T. gondii, all displaying an avidity IgG greater than 50 % and negative IgM, corresponding to a chronic stage of the infection. When correlating with the usual risk factors for the transmission of T. gondii, it was highlighted the presence of contact with cat feces (46.3 %) and the consumption of water directly from the tap (32.6 %). While with Chagas Disease (ChD), the presence of risk factors for acquiring the infection were highly demonstrated in the population, such as contact with triatomines (51.45 %) and living close to vegetation (49 %), however, only one pregnant woman (0.33 %) presented seropositivity for T. cruzi, without being related to the known risk factors. We conclude that T. gondii presents a high seroprevalence and T. cruzi an infrequent seroprevalence in the covered population, with high risk factors for cutaneous and oral vector transmission, representing a threat for the mother and the fetus. We recommend educating the population to reduce their exposure to risk factors.

Description of an oral Chagas disease outbreak in Venezuela, including a vertically transmitted case.

We describe the eleventh major outbreak of foodborne Trypanosoma cruzi transmission in urban Venezuela, including evidence for vertical transmission from the index case to her fetus. After confirming fetal death at 24 weeks of gestation, pregnancy interruption was performed. On direct examination of the amniotic fluid, trypomastigotes were detected. T. cruzi specific-polymerase chain reaction (PCR) also proved positive when examining autopsied fetal organs. Finally, microscopic fetal heart examination revealed amastigote nests. Acute orally transmitted Chagas disease can be life threatening or even fatal for pregnant women and unborn fetuses owing to vertical transmission. There is therefore an urgent need to improve national epidemiologic control measures.

Description of an oral Chagas disease outbreak in Venezuela, including a vertically transmitted case

We describe the eleventh major outbreak of foodborne Trypanosoma cruzi transmission in urban Venezuela, including evidence for vertical transmission from the index case to her fetus. After confirming fetal death at 24 weeks of gestation, pregnancy interruption was performed. On direct examination of the amniotic fluid, trypomastigotes were detected. T. cruzi specific-polymerase chain reaction (PCR) also proved positive when examining autopsied fetal organs. Finally, microscopic fetal heart examination revealed amastigote nests. Acute orally transmitted Chagas disease can be life threatening or even fatal for pregnant women and unborn fetuses owing to vertical transmission. There is therefore an urgent need to improve national epidemiologic control measures.

Orally-transmitted Chagas disease: Epidemiological, clinical, serological and molecular outcomes of a school microepidemic in Chichiriviche de la Costa, Venezuela.

Oral transmission of Trypanosoma cruzi is a frequent cause of acute Chagas disease (ChD). In the present cross-sectional study, we report the epidemiological, clinical, serological and molecular outcomes of the second largest outbreak of oral ChD described in the literature. It occurred in March 2009 in Chichiriviche de la Costa, a rural seashore community at the central littoral in Venezuela. The vehicle was an artisanal guava juice prepared at the local school and Panstrongylus geniculatus was the vector involved. TcI genotype was isolated from patients and vector; some showed a mixture of haplotypes. Using molecular markers, parasitic loads were high. Eighty-nine cases were diagnosed, the majority (87.5%) in school children 6-15 years of age. Frequency of symptomatic patients was high (89.9%) with long-standing fever in 87.5%; 82.3% had pericardial effusion detected by echocardiogram and 41% had EKG abnormalities. Three children, a pregnant woman and her stillborn child died (5.6% mortality). The community was addressed by simultaneous determination of specific IgG and IgM, confirmed with indirect hemagglutination and lytic antibodies. Determination of IgG and IgA in saliva had low sensitivity. No individual parasitological or serological technique diagnosed 100% of cases. Culture and PCR detected T. cruzi in 95.5% of examined individuals. Based on the increasing incidence of oral acute cases of ChD, it appears that food is becoming one of the most important modes of transmission in the Amazon, Caribbean and Andes regions of America.

Update on oral Chagas disease outbreaks in Venezuela: epidemiological, clinical and diagnostic approaches.

Orally transmitted Chagas disease has become a matter of concern due to outbreaks reported in four Latin American countries. Although several mechanisms for orally transmitted Chagas disease transmission have been proposed, food and beverages contaminated with whole infected triatomines or their faeces, which contain metacyclic trypomastigotes of Trypanosoma cruzi, seems to be the primary vehicle. In 2007, the first recognised outbreak of orally transmitted Chagas disease occurred in Venezuela and largest recorded outbreak at that time. Since then, 10 outbreaks (four in Caracas) with 249 cases (73.5% children) and 4% mortality have occurred. The absence of contact with the vector and of traditional cutaneous and Romana's signs, together with a florid spectrum of clinical manifestations during the acute phase, confuse the diagnosis of orally transmitted Chagas disease with other infectious diseases. The simultaneous detection of IgG and IgM by ELISA and the search for parasites in all individuals at risk have been valuable diagnostic tools for detecting acute cases. Follow-up studies regarding the microepidemics primarily affecting children has resulted in 70% infection persistence six years after anti-parasitic treatment. Panstrongylus geniculatus has been the incriminating vector in most cases. As a food-borne disease, this entity requires epidemiological, clinical, diagnostic and therapeutic approaches that differ from those approaches used for traditional direct or cutaneous vector transmission.

Update on oral Chagas disease outbreaks in Venezuela: epidemiological, clinical and diagnostic approaches

Orally transmitted Chagas disease has become a matter of concern due to outbreaks reported in four Latin American countries. Although several mechanisms for orally transmitted Chagas disease transmission have been proposed, food and beverages contaminated with whole infected triatomines or their faeces, which contain metacyclic trypomastigotes of Trypanosoma cruzi, seems to be the primary vehicle. In 2007, the first recognised outbreak of orally transmitted Chagas disease occurred in Venezuela and largest recorded outbreak at that time. Since then, 10 outbreaks (four in Caracas) with 249 cases (73.5% children) and 4% mortality have occurred. The absence of contact with the vector and of traditional cutaneous and Romana’s signs, together with a florid spectrum of clinical manifestations during the acute phase, confuse the diagnosis of orally transmitted Chagas disease with other infectious diseases. The simultaneous detection of IgG and IgM by ELISA and the search for parasites in all individuals at risk have been valuable diagnostic tools for detecting acute cases. Follow-up studies regarding the microepidemics primarily affecting children has resulted in 70% infection persistence six years after anti-parasitic treatment. Panstrongylus geniculatus has been the incriminating vector in most cases. As a food-borne disease, this entity requires epidemiological, clinical, diagnostic and therapeutic approaches that differ from those approaches used for traditional direct or cutaneous vector transmission.

The performance of laboratory tests in the management of a large outbreak of orally transmitted Chagas disease.

Orally transmitted Chagas disease (ChD), which is a well-known entity in the Brazilian Amazon Region, was first documented in Venezuela in December 2007, when 103 people attending an urban public school in Caracas became infected by ingesting juice that was contaminated with Trypanosoma cruzi. The infection occurred 45-50 days prior to the initiation of the sampling performed in the current study. Parasitological methods were used to diagnose the first nine symptomatic patients; T. cruzi was found in all of them. However, because this outbreak was managed as a sudden emergency during Christmas time, we needed to rapidly evaluate 1,000 people at risk, so we decided to use conventional serology to detect specific IgM and IgG antibodies via ELISA as well as indirect haemagglutination, which produced positive test results for 9.1%, 11.9% and 9.9% of the individuals tested, respectively. In other more restricted patient groups, polymerase chain reaction (PCR) provided more sensitive results (80.4%) than blood cultures (16.2%) and animal inoculations (11.6%). Although the classical diagnosis of acute ChD is mainly based on parasitological findings, highly sensitive and specific serological techniques can provide rapid results during large and severe outbreaks, as described herein. The use of these serological techniques allows prompt treatment of all individuals suspected of being infected, resulting in reduced rates of morbidity and mortality.

The performance of laboratory tests in the management of a large outbreak of orally transmitted Chagas disease

Orally transmitted Chagas disease (ChD), which is a well-known entity in the Brazilian Amazon Region, was first documented in Venezuela in December 2007, when 103 people attending an urban public school in Caracas became infected by ingesting juice that was contaminated with Trypanosoma cruzi. The infection occurred 45-50 days prior to the initiation of the sampling performed in the current study. Parasitological methods were used to diagnose the first nine symptomatic patients; T. cruzi was found in all of them. However, because this outbreak was managed as a sudden emergency during Christmas time, we needed to rapidly evaluate 1,000 people at risk, so we decided to use conventional serology to detect specific IgM and IgG antibodies via ELISA as well as indirect haemagglutination, which produced positive test results for 9.1%, 11.9% and 9.9% of the individuals tested, respectively. In other more restricted patient groups, polymerase chain reaction (PCR) provided more sensitive results (80.4%) than blood cultures (16.2%) and animal inoculations (11.6%). Although the classical diagnosis of acute ChD is mainly based on parasitological findings, highly sensitive and specific serological techniques can provide rapid results during large and severe outbreaks, as described herein. The use of these serological techniques allows prompt treatment of all individuals suspected of being infected, resulting in reduced rates of morbidity and mortality.

Despistaje de toxoplasmosis y enfermedad de Chagas en la consulta prenatal del Hospital Universitario de Caracas / Sereening of toxoplasmosis and Chagas disease in the prenatal consultation of the Hospital Universitario de Caracas

Determinar seropositividad para Toxoplasma gondii y Trypanosoma cruzi en embarazadas, Estudio analítico transversal realizado en 678 gestantes. Para la detección de anticuerpos anti-Toxoplasma se utilizó ELISA para la captura de IgM, IgG y avidez de IgG. Para T. cruzi se realizó ELISA IgG y hemaglutinación indirecta. Consulta Prenatal del Hospital Universitario de Caracas. El mayor número de pacientes se ubicó en el grupo etario 16 - 20 años, 42 por ciento cursaba su primer embarazo, 25 por ciento el segundo y 33 por ciento tenía 3 o más. El 39 por ciento se encontraba en el primer trimestre del embarazo, 43 por ciento en el segundo y 18 por ciento en el tercero. El despistaje para T. cruzi no mostró ninguna persona reactiva. Se presentó infección toxoplásmica por ELISA IgG en 38 por ciento de las embarazadas de las cuales 10 pudieran corresponder a infecciones recientes por tener IgM positiva o baja avidez de anticuerpos específicos, 8 de ellas se encontraban en el primero o segundo trimestre del embarazo. Una segunda serología en 54 mujeres no reveló seroconversión. La seropositividad para toxoplasmosis fue alta y detectó algunas embarazadas con infección reciente encontrándose la mayoría en los dos primeros trimestres, cuando hay riesgo de malformaciones congénitas. La combinación de estas técnicas en toxoplasmosis permite estimar tiempo de evolución y su aplicación en consultas prenatales permitiría detectar infecciones recientes para tratamiento oportuno. Es igualmente importante insistir en la obligatoriedad del diagnóstico de enfermedad de Chagas por ser transmisible al feto y encontrarse Venezuela entre los países endémicos

To determine seropositivity for Toxoplasma gondii and Trypanosoma cruzi in pregnant women. A cross-sectional analytical study was conducted at 678 pregnant women. ELISA was used for the detection of anti-Toxoplasma antibodies IgM, IgG and IgG avidity. For T. cruzi IgG ELISA was performed and Indirect Hemagglutination Test. Prenatal care at the Hospital Universitario de Caracas. The highest number of patients was located in the age group 16 to 20 years, 42 percent was in her first pregnancy, 25 percent the second and 33 percent had 3 or more. The 39 percent was in the first trimester, 43 percent in the second and 18 percent in the third. The screening for T. cruzi showed no reactive person. Toxoplasmic infection was presented by IgG ELISA in 38 percent of pregnant women of which 10 might be due to recent infections by having a positive IgM or low avidity of specific antibodies, 8 of them were in the first or second trimester of pregnancy. A second serology in 54 women did not show seroconversion. Toxoplasmosis seropositivity was high and detected some pregnant women with recent infection in the first two quarters, when there is risk of congenital malformations. The combination of these techniques in Toxoplasmosis can estimate time of evolution and its application in prenatal consultations would detect recent infections. It is equally important to emphasize the obligation of the diagnosis of Chagas’ disease which can be transmitted to the fetus and also because Venezuela is an endemic country

Large urban outbreak of orally acquired acute Chagas disease at a school in Caracas, Venezuela.

BACKGROUND: Trypanosoma cruzi oral transmission is possible through food contamination by vector's feces. Little is known about the epidemiology and clinical features of microepidemics of orally acquired acute Chagas disease (CD). METHODS: A case-control, cohort-nested, epidemiological study was conducted during an outbreak of acute CD that affected a school community. Structured interviews were designed to identify symptoms and sources of infection. Electrocardiograms were obtained for all patients. Specific serum antibodies were assessed by immunoenzimatic and indirect hemagglutination tests. In some cases, parasitemia was tested directly or by culture, animal inoculation, and/or a polymerase chain reaction technique. RESULTS: Infection was confirmed in 103 of 1000 exposed individuals. Of those infected, 75% were symptomatic, 20.3% required hospitalization, 59% showed ECG abnormalities, parasitemia was documented in 44, and 1 child died. Clinical features differed from those seen in vectorial transmission. The infection rate was significantly higher among younger children. An epidemiological investigation incriminated contaminated fresh guava juice as the sole source of infection. CONCLUSIONS: This outbreak was unique, because it affected a large, urban, predominantly young, middle-class, otherwise healthy population and resulted in an unprecedented public health emergency. Rapid diagnosis and treatment avoided higher lethality. Food-borne transmission of T. cruzi may occur more often than is currently recognized.

[A confirmatory diagnosis of antibodies anti-Trypanosoma cruzi in donors referred by blood banks in Venezuela]. / Diagnóstico confirmatorio de anticuerpos anti-Trypanosoma cruzi en donantes referidos por bancos de sangre en Venezuela.

To establish the confirmatory diagnosis of Trypanosoma cruzi infection, at least two immunoserological tests (ELISA, Indirect hamaglutination, IH, Complement Fixation Test, CFT) were carried out in 254 donors, from public and private blood banks of Venezuela, during 48 months between 1997-1998 and 2003-2004, referred to the Immunology Section of the Tropical Medicine Institute in Caracas. Antibodies anti-T. cruzi were detected in 129/254 (50,79%) by ELISA-IgG or IH and CFT. The "artificial xenodiagnosis" was positive in 10/118 persons with positive confirmed serology. Of 129 donors found positive by the serological tests, 68 were living in the capital region and 61 in the interior of the country. Likewise 113 were born in the interior of the country, 8 in Caracas and 8 in Colombia. Of them, 12 individuals serologically confirmed declared to have donated blood in a minimum of 4 occasions before diagnosis. The present study emphasizes the importance of detection of antibodies against T. cruzi in the integral evaluation of blood donors, since many of them with antibodies anti-T. cruzi, have donated blood several times previous to diagnosis.

Diagnóstico confirmatorio de anticuerpos anti-Trypanosoma cruzi en donantes referidos por bancos de sangre en Venezuela / A confirmatory diagnosis of antibodies anti-Trypanosoma cruzi in donors referred by blood banks in Venezuela

Con el objetivo de establecer el diagnóstico confirmatorio para Trypanosoma cruzi se realizaron al menos dos pruebas inmunoserológicas (ELISA, Reacción de Hemoaglutinación Indirecta, RHI, o Reacción de Fijación de Complemento, RFC) a donantes provenientes de bancos de sangre de centros asistenciales públicos y privados de Venezuela que acudieron durante 48 meses entre los años 1997-1998 y 2003-2004 a la Sección de Inmunología del Instituto de Medicina Tropical en Caracas, Venezuela. Se evaluaron 254 donantes referidos de diferentes bancos de sangre por presentar anticuerpos anti-T. cruzi en pruebas de despistaje. Se con firmó la presencia de anticuerpos en 129/254 (50,79 por ciento) de los individuos por las técnicas de ELISA-IgG o RHI y RFC. El “xenodiagnóstico artificial” fue positivo en 10/118 (8,5 por ciento) personas con serología positiva. De 129 donantes en contra dos reactivos por técnicas serológicas, 68 eran residentes de la región capital y 61 del interior del país. Así mismo, 113 nacieron en el interior del país, 8 en Caracas y 8 en Colombia. En 12 individuos con firma dos serológicamente se constató la donación de sangre en mínimo 4 ocasiones antes de detectar la infección. El presente estudio resalta la importancia de la búsqueda activa de individuos con Enfermedad de Chagas a través de la detección de anticuerpos contra T. Cruzi en la evaluación integral de donantes de sangre para descartar el riesgo de transmisión a otras personas. Muchos de estos donantes con anticuerpos anti-T. cruzi, la gran mayoría clínicamente asintomáticos, habían donado sangre en varias ocasiones previas al diagnóstico.