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.

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.

Estandarización de ELISA para el diagnóstico de fasciolosis bovina, ovina y humana / Standardization of ELISA for the diagnosis of bovine, ovine and human fasciolosis

RESUMEN Introducción: La fasciolosis representa un grave problema para el sector pecuario y la salud humana en muchos países. En Colombia, afecta principalmente al ganado bovino y ovino, con escasos reportes en humanos. Objetivo: Estandarizar un Ensayo de Inmunoadsorción Enzimática para bovinos, ovinos y humanos como herramienta de tamizaje de fasciolosis. Metodología: Se utilizaron 50 muestras de bovinos, 50 de ovinos y 39 de humanos con diagnóstico de fasciolosis confirmado por serología y examen de materia fecal. Se utilizaron cuatro presentaciones del antígeno excretor-secretor de Fasciola hepatica. Se calcularon la sensibilidad, la especificidad y la concordancia. Resultados: La sensibilidad del ELISA en humanos, ovinos y bovinos fue de 100% y la especificidad fue de 97%, 85,2% y 96,2%, respectivamente. El coeficiente Kappa de Cohen fue superior a 0,8 en las tres especies. Conclusiones: La prueba de ELISA estandarizada para el diagnóstico de la fasciolosis humana, ovina y bovina demostró una excelente sensibilidad y buena especificidad. Se propone realizar la validación a mayor escala para su posterior uso como herramienta en el tamizaje de esta parasitosis.

ABSTRACT Introduction: Fascioliasis represents a serious problem for livestock production and human health in the world. In Colombia, it mainly affects bovine and ovine cattle, with few cases reported in humans. Objective: To standardize an Enzyme-Linked ImmunoSorbent test (ELISA) in bovine, ovine, and human individuals as a screening tool of fascioliasis. Methods: 50 bovine, 50 ovine and 39 human samples with fascioliasis confirmed by serology and stool test were used. Sensitivity, specificity and concordance were calculated. Results: Sensitivity of the ELISA in humans, bovine and ovine cattle was 100 % and specificity was 97%, 85.2% and 96.2%, respectively. Cohen´s Kappa coefficient was >0.8 in all groups. Conclusions: Standardized ELISA test for bovine, ovine and human fascioliasis exhibited an excellent sensitivity and good specificity. It is proposed to carry out a large-scale validation for its ulterior use as a screening tool for the diagnosis of this parasitic infection.

Long-term comparative pharmacovigilance of orally transmitted Chagas disease: first report.

BACKGROUND: Two old drugs are the only choice against Trypanosoma cruzi and little is known about their secondary effects in the acute stage of oral-transmitted Chagas disease (ChD). METHODS: A cross-sectional analytical surveillance study was conducted in a sizable cohort of patients seen during the largest acute foodborne ChD microepidemic registered so far. Individuals were treated with benznidazole (BNZ) or nifurtimox (NFX). 'Common Terminology Criteria for Adverse Events' was assessed to categorize side effects according to severity. RESULTS: Out of 176 treatments applied, 79% had one or more adverse effects, which predominated in adults (97.8%) as compared to children (75.5%). Risk of side effects with NFX was significantly higher than BNZ. Four adults and a child treated with NFX had severe side effects (pulmonary infarction, facial paralysis, neutropenia, blurred vision, bone marrow hypoplasia) warranting hospitalization, and drug suspension. Adverse effects frequently reported with NFX were abdominal pain, hyporexia, weight loss, headache, nausea and lymphocytosis, whereas skin rash, neurosensory effects, hyporexia, fatigue, pyrosis, abdominal pain and eosinophilia were observed with BNZ. CONCLUSIONS: Frequency and severity of side effects during treatment of acute oral infection by T. cruzi demand direct supervision and close follow-up, even in those asymptomatic, to prevent life-threatening situations.

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.

Hidatidosis poliquística autóctona en dos pacientes Yanomami en el Alto Orinoco, Amazonas, Venezuela / Polycystic hydatid disease in two patients indigenous Yanomami in the Upper Orinoco, Amazonas, Venezuela

La infección por Echinococcus sp. es hipoendémica en Venezuela. Sólo cuatro casos de hidatidosis autóctona por E. vogeli han sido reportados, tres de ellos en la región de la Guayana venezolana. En Febrero del año 2009 se realizó el diagnóstico clínico-sero-epidemiológico de hidatidosis poliquística en una paciente femenina de la etnia Yanomami, procedente de Parima B, Alto Orinoco, en la Amazonía venezolana. Se resolvió con tratamiento médico y quirúrgico por laparoscopia y se evidenció en el quiste la presencia de ganchos rostelares compatibles con E. vogeli. En Abril del 2009 en una segunda paciente Yanomami de igual procedencia, se le diagnosticó hidatidosis por E. vogeli siendo operada exitosamente por cirugía laparoscópica asistida por robot. Dos casos humanos en una misma población y la presencia de factores de riesgo como la tenencia de perros domésticos y la comunicación por informantes indígenas del hallazgo de quistes en hígados de animales de cacería (Cuniculus paca o lapa y Dasyprocta sp. o picure), hacen pensar en transmisión activa en la cuenca del Alto Orinoco y en zonas selváticas de la Guayana venezolana. El presente, es el primer registro de casos de hidatidosis poliquística en indígenas de la etnia Yanomami.

Infection by Echinococcus sp. is hypoendemic in Venezuela. Only four cases of autochthonous E. vogeli hydatidosis have been reported, including three in the Venezuelan region of Guayana. In February 2009, based on epidemiological data, signs and symptoms and serological tests, a female patient of the Yanomami ethnic group, was diagnosed with a polycystic hydatid disease in Parima B, Alto Orinoco, in the Venezuelan Amazon. Rostellar hooks compatible with E. vogeli were found in the cyst. It was resolved with medical and surgical treatment by laparoscopy. A second Yanomami patient from the same location was diagnosed with E. vogeli hydatidosis in April 2009, being successfully operated with robot-assisted laparoscopy. Two human cases in the same population and the presence of risk factors such as domestic dog ownership and findings of cysts in livers of hunted animals (such as Cuniculus and Dasyprocta sp.) reported by indigenous informants, suggest active transmission in the Upper Orinoco basin and forested areas of the Venezuelan Guayana. These are the first reported cases of polycystic hydatid disease of the Yanomami ethnic group.

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.

La transmisión oral en la enfermedad de chagas / The oral transmission of Chagas disease

La Enfermedad de Chagas se transmite al hombre por varios mecanismos participando en algunos, el vector de manera directa ó indirecta. En otras ocasiones, la transmisión de hombre a hombre ocurre a través de transfusiones, trasplantes de órganos y transplacentaria, y menos frecuente por la manipulación de tejidos, líquidos de animales infectados ó accidentes de laboratorio. La transmisión oral por contaminación de alimentos con el contenido intestinal de triatominos infectados con Trypanosoma cruzi ha sido un mecanismo demostrado experimentalmente en animales. Esta particular vía, probablemente la más común entre los animales silvestres, asociado a la constitución bioquímica de los aislados, ha sido responsable de numerosos brotes en Brasil. En Venezuela se han descrito cuatro episodios desde 2007 con 228 casos y 6 fallecimientos. Las medidas de vigilancia epidemiológica y control sanitario deben basarse en el estudio del comportamiento de los vectores, identificación de los factores de riesgo y en la concientización de personal de salud y autoridades sanitarias de que ésta es una modalidad de transmisión de T. cruzi por alimentos, definitivamente demostrada en Venezuela.

Chagas Disease is transmitted to humans through various mechanisms in which the vector directly or indirectly can participate. In other circumstances, infection from man to man occurs through blood transfusions, organ transplants and transplacental route and less often, by the manipulation of tissue fluids from infected animals or laboratory accidents. Oral transmission through food contamination with the intestinal content of triatomines infected with Trypanosoma cruzi has been demonstrat ed experimentally in animals. This particular way, probably the most common among wild animals, will depend on the biochemical constitution of the isolates and it has been responsible for numerous outbreaks in Brazil. In Venezuela, four episodes have been reported since 2007 with 228 cases and 6 deaths. The measures of surveillance and disease control by the health authorities should be based on the study of the behavior of the vectors, identification of the main risk factors for the human population and awareness of the health staff and health authorities, that this way of transmission is definitely established in Venezuela.

Estudio de la fasciolosis hepática humana y parasitosis intestinales en el caserío Mesa Arriba del municipio Carache, estado Trujillo,Venezuela / Study of human hepatic fasciolosis and intestinal parasitosis in the Mesa Arriba Village, Carache Municipality, Trujillo State, Venezuela

Se realizó un estudio clínico epidemiológico para determinar la ocurrencia de fasciolosis hepática humana y parasitosis intestinales en el caserío Mesa Arriba, municipio Carache. estado Trujillo, Venezuela, zona descrita como endémica para fasciolosis bovina, donde dos casos aislados, se han reportado en humanos. Se estudiaron 98 personas previo consentimiento informado, a quienes se les realizó una encuesta epidemiológica, examen físico, hematología, aminotransferasas, estudio coproparasitológico y serológico: ELISA con antígeno de excreción-secreción de adultos de Fasciola hepatica (AFhES) y “Western blot”(WB). Con base en los datos obtenidos, se conoció que el 88,8% de los participantes había consumido berro silvestre (Rorippa nasturtium aquaticum) y 59,2% tuvo contacto con ganado vacuno. En el estudio coproparasitológico se encontró que el 47,9% presentó algún tipo de parásito intestinal, 20,4% correspondió a helmintos, 15,3% a protozoarios y 12,2% a infecciones mixtas. No se encontraron huevos de Fasciola hepatica. El 18,4% de las personas mostró eosinofilia. Se obtuvo un suero positivo por el método de ELISA, con bandas inespecíficas al WB-AFhES. Se administró tratamiento específico para parásitos intestinales. No se demostró fasciolosis humana en este trabajo, a pesar de encontrar factores favorables a la infección, pero el mismo representó una aproximación a su estudio epidemiológico en el estado Trujillo.

A clinical-epidemiological study to determine the occurrence of human hepatic fasciolosis and intestinal parasitosis was done at the Mesa Arriba Village, Carache Municipality, Trujillo State, Venezuela, area which has been described as endemic for bovine fasciolosis and where two isolated cases have been reported in humans. The study included 98 persons who, after previously signing an informed consent form, answered an epidemiological survey and were physically examined and submitted to the following laboratory tests: complete hematology, aminotransferase, and coproparasitology and serology; ELISA using Fasciola hepatica adult excretion-secretion antigen (AFhES) and “Western Blot” (WB). Based on the results obtained, it was found that 88.8% of participants had consumed wild watercress (Rorippa nasturtium aquaticum) and 59.2% had contact with bovine cattle. The coproparasitological study showed that 47.9% had some type of intestinal parasite: 20.4% corresponded to helmints, 15.3% to protozoa, and 12.2% mixed infections. There were no Fasciola hepatica eggs; 18.4% of the individuals showed eosinophilia. The ELISA test gave one positive serum with non-specific WB-AFhES bands. Specific anti-intestinal parasite treatment was indicated. Human fasciolosis was not demonstrated in this study, in spite of finding favorable factors for this infection, but is represents and approximation to its epidemiological study at Trujillo State.

Fasciolosis humana en el municipio Mara estado Zulia Venezuela: prevalencia y factores asociados / Human fasciolosis in Mara municipality Zulia state Venezuela: prevalence and asociated factors

La Fasciolosis humana tiene baja frecuencia en Venezuela; sin embargo, el Municipio Mara es una región altamente endémica para fasciolosis bovina y no existen estudios sobre esta infección parasitaria en humanos. Con el propósito de determinar la prevalencia y factores asociados a la fasciolosis humana en el municipio Mara del estado Zulia, se recolectaron un total de 51 muestras de sangre y de heces. Los sueros se procesaron mediante la técnica de ELISA y “Western blot” (WB) con antígenos excreción-secreción de Fasciola hepatica (AFhES). A los sueros que resultaron positivos se les realizó ELISA IgG anti Toxocara spp, Toxoplasma gondii y cisticerosis. Las muestras de heces se concentraron mediante las técnicas de Ritchie y sedimentación rápida. Dos sueros (3,9 por ciento) fueron positivos a la técnica de ELISA AFhES; estos no reconocieron las moléculas específicas del WB-AFhES, detectadas por sueros de pacientes con infección absolutamente demostrada. Ambos individuos resultaron negativos a IgG anti Toxocara spp, Toxoplasma gondii y cisticerosis, así como también a parásitos intestinales. La prevalencia general de las parasitosis intestinales fue de 52,9 por ciento (27/51), siendo más frecuente los protozoarios que los helmintos. No se encontraron huevos de F. hepatica. Los dos individuos positivos a ELISA AFhES tenían en común trabajar en el corte de pasto fresco. Los resultados obtenidos sugieren que la población ha estado en contacto con F. hepatica, en ausencia de una infección activa por la falta de reconocimiento de las moléculas específicas del WB-AFhES y la ausencia de huevos en las heces. La fasciolosis humana tiene una baja frecuencia en Venezuela, razón por la cual no es sospechada su presencia, existiendo poco conocimiento de esta infección por el personal de salud y la población general.

In Venezuela, human Fasciolosis shows a low frequency. However, Mara Municipality is a highly endemic region for bovine fasciolosis and there are no reports of this parasite infection in humans. To determine the prevalence and associated factors to human fasciolosis in Mara municipality - Zulia state, a total of 51 blood and stool samples were collected. Serums were tested by ELISA and Western Blot (WB) assays, with excretion-secretion antigens of Fasciola hepatica (AFhES). The serum samples that resulted positive by these assays were tested by ELISA IgG anti Toxocara sp, Toxoplasma gondii and cysticerosis. Stool samples were concentrated by the Ritchie and rapid sedimentation techniques. Two serum samples were reactive to ELISA AFhES (3.9 percent) and these did not recognize the specific molecules of WB-AFhES detected by serum from patients with an absolutely demonstrated infection. Both participants were not positive to IgG anti Toxocara sp, Toxoplasma gondii, cysticerosis, and stool samples of these were negative to intestinal parasites. The general prevalence of intestinal parasites was 52.9 percent (27/51), being protozoa more frequent than helminthes. No Fasciola eggs were found. The two positives participants had in common that both had worked as fresh pasture cutters. These results suggest that the population had been in contact with F. hepatica, with no active infection because of the lack of specific molecules recognition and the absence of eggs in stool samples. Human fasciolosis has a low frequency in Venezuela and is underestimated and underrecognized by health workers and the general population.

[Human fasciolosis in Mara municipality, Zulia state. Venezuela: prevalence and asociated factors]. / Fasciolosis humana en el municipio Mara, estado Zulia, Venezuela: prevalencia y factores asociados.

In Venezuela, human Fasciolosis shows a low frequency. However, Mara Municipality is a highly endemic region for bovine fasciolosis and there are no reports of this parasite infection in humans. To determine the prevalence and associated factors to human fasciolosis in Mara municipality - Zulia state, a total of 51 blood and stool samples were collected. Serums were tested by ELISA and Western Blot (WB) assays, with excretion-secretion antigens of Fasciola hepatica (AFhES). The serum samples that resulted positive by these assays were tested by ELISA IgG anti Toxocara sp, Toxoplasma gondii and cysticerosis. Stool samples were concentrated by the Ritchie and rapid sedimentation techniques. Two serum samples were reactive to ELISA AFhES (3.9%) and these did not recognize the specific molecules of WB-AFhES detected by serum from patients with an absolutely demonstrated infection. Both participants were not positive to IgG anti Toxocara sp, Toxoplasma gondii, cysticerosis, and stool samples of these were negative to intestinal parasites. The general prevalence of intestinal parasites was 52.9% (27/51), being protozoa more frequent than helminthes. No Fasciola eggs were found. The two positives participants had in common that both had worked as fresh pasture cutters. These results suggest that the population had been in contact with F. hepatica, with no active infection because of the lack of specific molecules recognition and the absence of eggs in stool samples. Human fasciolosis has a low frequency in Venezuela and is underestimated and underrecognized by health workers and the general population.

Antígeno excreción-secreción de Fasciola hepatica: ultrafiltración y aplicación en inmunodiagnóstico / Fasciola hepatica excretion-secretion antigen: ultrafiltration and application in immunodiagnosis

La baja sensibilidad de la coprología en el diagnóstico de la fasciolosis humana ha motivado el desarrollo del inmunodiagnóstico. El antígeno de excreción-secreción de adultos de Fasciola hepatica (AFhES) en ELISA es adecuado para el screening, aunque sobrestima la prevalencia; cuando se utiliza en Western blot (WB) no muestra un buen reconocimiento de sus componentes. Para lograr una mejor preparación, se ultrafiltró el antígeno a través de membranas YM de 10, 30 y 50 kDa. Los retenidos (R) se usaron en ELISA y WB. La mayor discriminación entre positivos y negativos en ELISA y la mejor resolución en el reconocimiento al antígeno en WB, se logró con la fracción R50. Se destacan las moléculas de 9, 14, 65 kDa y la región alrededor de 27 kDa, detectadas con alta sensibilidad (90 al 100% de los sueros positivos) y especificidad (por ningún negativo). Al ensayar 29 sueros con otras parasitosis, sólo el de una persona con Paragonimus sp. reaccionó a la molécula de 65 kDa. ELISA-AFhES con todas las fracciones filtradas fue útil, facilitando el screening de la infección, aunque con R50 se obtuvieron los mejores resultados. La comprobación de los casos positivos se logra eficientemente utilizando la fracción R50 del AFhES en WB.

Low sensitivity in the coprologic diagnosis of human fasciolosis has motivated the development of immunodiagnosis. The excretion-secretion antigen from Fasciola hepatica adult worms (ESAFh) with ELISA is suitable for screening, although it overestimates its prevalence. However, when tested by Western blot (WB) it does not show any optimal recognition of its components. In order to obtain a better preparation, the antigen was ultrafiltered by YM 10, 30 and 50 kDa membranes. Retentates (R) were used by ELISA and WB. A higher discrimination between positives and negatives by ELISA and a better resolution in the antigen recognition in WB was achieved with the R50 fraction. Molecules of 9, 14, 65 kDa, and region about 27 kDa were detected with high sensitivity (90 to 100% of positive sera) and specificity (none of the negative sera). Among the 29 sera with other parasitic diseases, only one with Paragonimus sp. reacted to the 65 kDa molecule. ELISA-ESAFh with all filtrated fractions was useful, facilitating the infection screening even though the best results were obtained with R50. The verification of positive cases is efficiently achieved using the R50 of the ESAFh fraction by WB.

Brote familiar de fascioliasis en Venezuela / Family outbreak of fascioliasis in Venezuela

De los 9 casos de fascioliasis humana registrados en Venezuela, 4 han sido publicados en los últimos 10 años, siendo 2 de éstos procedentes de la región andina. El riesgo de endemicidad frecuente en bovinos y la condición clínica de una niña de 14 años, con malestar abdominal, vómitos, eosino filia y antecedentes de ingestión abundante de berros, motivó realizar un estudio en su lugar de procedencia (Timotes, Edo. Mérida), para conocer la exposición de la comunidad al riesgo de infección. Se evaluaron 65 personas, a quienes se les realizó historia clínica, con consentimiento previa información, toma de muestras de sangre, exámenes de heces (n=37) y ecografía abdominal (n=33). Se practicó ELISA con extracto soluble de adultos de Fasciola hepatica (ELISA-AFhES), resultando 9 personas positivas. Se practicó “Western blot” (WB) a todos los sueros positivos en ELISA, de los cuales 5 reconocieron moléculas específicas de 9, 14, 27 y 65 kDa, lo que constituye un patrón de positividad al WB. Los cuatro sueros restantes, con débil reactividad al ELISA, no reconocieron estas moléculas. Por estudios coprológicos se encontraron Entamoeba coli, Entamoeba histolytica/dispar, Blastocystis hominis, Giardia lamblia, Endolimax nana y Ascaris lumbricoides. Tres de las 5 personas positivas por ELISA-AFhES y WB-AFhES resultaron con huevos de Fasciola hepatica en las heces. Los 5 pasos positivos corresponden a niñas de una familia, todas hermanas, cuyos padres resultaron sin infección, a pesar de que todos ingieren berros y ensaladas con productos de la región. El presente estudio constituye el primer reporte de transmisión a humanos en una población de un área bien delimitada en la región andina venezolana.

Low transmission areas of schistosomiasis in Venezuela: consequences on the diagnosis, treatment, and control

Schistosomiasis low transmission areas as Venezuela, can be defined as those where the vector exists, the prevalence of active cases is under 25 percent, individuals with mild intensity of infection predominate and are mostly asymptomatic. These areas are the consequence of effective control programs, however, "silent" epidemiological places are difficult to trace, avoiding the opportune diagnosis and treatment of infected persons. Clinic and abdominal ultrasound have not shown to discriminate infected from uninfected persons in areas where besides Schistosoma mansoni, intestinal parasites are the rule. Under these conditions, serology remains as a very valuable diagnostic tool, since it gives a closer approximation to the true prevalence. In this sense, circumoval precipitin test, ELISA-SEA with sodium metaperiodate, and alkaline phosphatase immunoassay joined to coprology allow the identification of the "schistosomiasis cases". In relation to public health, schistosomiasis has been underestimated by the sanitary authorities and the investment on its control is being transferred to other diseases of major social and political relevance neglecting sanitary efforts and allowing growth of snail population. Some strategies of diagnosis and control should be done before schistosomiasis reemergence occurs in low transmission areas.

Localización pancreática de fasciola hepática en un caso humano autóctono proveniente del Edo. Bolívar, Venezuela

La fasciolosis humana es una entidad poco frecuente reportada previamente 8 veces en Venezuela, de personas provenientes del centro y los estados occidentales. Se presenta el caso de un paciente masculino de 25 años, natural y procedente del Estado Bolívar, donde practica equitación y supervisa tareas de corral del ganado equino y bovino. La enfermedad actual se inicia con diarreas desde los 14 años, acompañada de persistente eosinofilia. ELISA e "Immunoblot", resultaron francamente positivos al antígeno de excreción- secreción de Fasciola hepática. Ante persistente dolor epigástrico, se practicó eco-endoscopia, resultando en la visualización de dilatación quística del ducto pancreático con una estructura interna probablemente correspondiente a un parásito. El examen parasitológico del contenido duodenal y heces reportó huevos de Fasciola hepática en este último material. Se administró tratamiento con Bithionol luego de lo cual disminuyó la eosinofilia y hubo franca mejoría clínica. Es el primer caso de fasciolosis humana proveniente del sureste del país, donde la fasciolosis bovina o humana no había sido descrita y en el cual además, ocurrió una localización ectópica pancreática de difícil diagnóstico clínico.

Human fasciolosis in Venezuela is an infrequent disease, reported only 8 times previously in persons coming from the center and the western states of the country. The case of a 25 years old masculine patient from Bolivar State, where he practices equitation and supervises tasks of corral of equine and bovine cattle is reported. The disease began with diarrhea at 14 years old, accompanied by persistent eosinofilia. ELISA and "Immunoblot" were strongly positive to excretion-secretion Fasciola hepatica antigen. Given the presence of persistent epigastric pain, echo-endoscopy was practiced, resulting in the visualization of cyst expansion of the pancreatic duct with an internal structure probably corresponding to a parasite. The parasitologic examination of the duodenal content and feces reported Fasciola hepatica eggs this last material. After treatment with Bithionol, eosinofilia diminished and there was frank clinical improvement. It is the first case of human fasciolosis of the southeastern part of the country, where bovine or human fasciolosis had not been described in which additionally, an ectopic pancreatic location of difficult clinical diagnosis occurred.

Low transmission areas of schistosomiasis in Venezuela: consequences on the diagnosis, treatment, and control.

Schistosomiasis low transmission areas as Venezuela, can be defined as those where the vector exists, the prevalence of active cases is under 25%, individuals with mild intensity of infection predominate and are mostly asymptomatic. These areas are the consequence of effective control programs, however, "silent" epidemiological places are difficult to trace, avoiding the opportune diagnosis and treatment of infected persons. Clinic and abdominal ultrasound have not shown to discriminate infected from uninfected persons in areas where besides Schistosoma mansoni, intestinal parasites are the rule. Under these conditions, serology remains as a very valuable diagnostic tool, since it gives a closer approximation to the true prevalence. In this sense, circumoval precipitin test, ELISA-SEA with sodium metaperiodate, and alkaline phosphatase immunoassay joined to coprology allow the identification of the "schistosomiasis cases". In relation to public health, schistosomiasis has been underestimated by the sanitary authorities and the investment on its control is being transferred to other diseases of major social and political relevance neglecting sanitary efforts and allowing growth of snail population. Some strategies of diagnosis and control should be done before schistosomiasis reemergence occurs in low transmission areas.