Regla de predicción para determinar infestación canina por Echinococcus granulosus / Prediction rule to determine canine infestation by Echinococcus granulosus

Nuestro objetivo fue determinar un score que ayude a predecir la probabilidad de infestación canina por Echinococcus en una zona endémica en hidatidosis. Se realizó un estudio longitudinal en 3 anexos de la provincia de Concepción ubicado en los andes centrales de Perú. La infección canina por Echinococcus granulosus fue definido por la presencia de antígeno identificado en la muestra de heces. El modelo predictivo se obtuvo mediante un análisis de regresión logística basado en los parámetros sociodemográficos, esta regla fue internamente validada por remuestreo de tipo bootstrap. Resultados: De 152 canes que se sometieron al estudio de heces, 76 tuvieron infección por Echinococcus confirmada por antígeno reactivo. Se identificaron 4 factores ponderados dentro de la regla de predicción que, en suma, dieron el puntaje: El can que duerme fuera de casa (3 puntos), alimentar con vísceras crudas al can (3 puntos) y sacrificar al ganado dentro de la casa (2 puntos) y el can se alimenta con croquetas (-2 puntos). Se encontró que esta regla de predicción tuvo valor del área bajo la curva ROC 0,78; (IC 95%: 0,70 ­ 0,86). Estos parámetros de predicción con un puntaje ≥ 3 tenía una sensibilidad del 75% y especificidad del 65,8%, con un valor predictivo positivo del 85,3%. Esta regla ayudará al personal de la salud a identificar a los canes infestados por Echinococcus granulosus, para su intervención anti parasitaria y preventiva en sus dueños(AU)

Cystic hydatidosis is an endemic disease in Andean regions, our objective was to determine a score that helps to predict canine Echinococcus infestation in an endemic area with hydatidosis. A longitudinal study was carried out in 3 annexes of the province of Concepción located in the central Andes of Peru. Canine echinococcosis infection was defined by the presence of E. granulosus antigen identified in the stool sample. The predictive model was obtained through a logistic regression analysis based on the sociodemographic parameters, this rule was internally validated by bootstrap type resampling. Results: Of 152 dogs that underwent the stool study, 76 had an Echinococcus infection confirmed by reactive antigen. Four weighted factors were identified within the prediction rule that, in sum, gave the score: The dog that sleeps outside the home (3 points), feeding raw viscera to the dog (3 points), slaughtering the cattle inside the house (2 points) and the dog is fed with croquettes (-2 points). This prediction rule was found to have a value of the area under the ROC curve 0.78 (95% CI: 0.70 - 0.86). At a cutoff point of ≥ 3 points, the prediction rule was found to have a sensitivity of 75% and a specificity of 65.8%, with a positive predictive value of 85.3%. This rule will help health personnel to identify canes infested by Echinococcus granulosus, for their anti-parasitic and preventive intervention in their owners(AU)

Identifying Trypanosoma cruzi discreet typing units in triatomines collected in different natural regions of Perú.

INTRODUCTION: Trypanosoma cruzi has been divided by international consensus into six discrete typing units (DTU): TcI, TcII, TcIII, TcIV, TcV y TcVI. The factors determining the dynamics of T. cruzi genotypes vector transmission of Chagas' disease in the different geographical regions of Perú are still unknown. OBJECTIVE: To detect and type T. cruzi DTUs from the faeces of seven species of triatomines (Panstrongylus chinai, P. geniculatus, P. herreri, Rhodnius robustus, R. pictipes, Triatoma carrioni and T. infestans) captured in eight departments from different natural regions of Perú. MATERIALS AND METHODS: We examined 197 insects for detecting trypanosomes. DNA was extracted from each insect intestinal contents and PCR amplification of kDNA, SL-IR, 24Sα rRNA and 18Sα RNA was performed for detecting T. cruzi DTUs. RESULTS: Five T. rangeli and 113 T. cruzi infections were detected; 95 of the latter were identified as TcI (two in P. chinai, one in P. geniculatus, 68 in P. herreri, four in R. pictipes, seven in R. robustus, one in T. carrioni, 12 in T. infestans), five as TcII (four in P. herreri, one in T. infestans), four as TcIII (three in P. herreri, one in R. robustus) and four TcIV infections in P. herreri. CONCLUSIONS: This is the first study which has attempted a large-scale characterization of T. cruzi found in the intestine of epidemiologically important vectors in Perú, thus providing basic information that will facilitate a better understanding of the dynamics of T. cruzi vector transmission in Perú.

Detección de unidades discretas de tipificación de Trypanosoma cruzi en triatominos recolectados en diferentes regiones naturales de Perú / Identifying Trypanosoma cruzi discreet typing units in triatomines collected in different natural regions of Perú

Resumen Introducción. Trypanosoma cruzi se ha dividido en seis unidades taxonómicas discretas (Discreet Typing Units, DTU) denominadas TcI, TcII, TcIII, TcIV, TcV y TcVI. Aún se desconocen los factores determinantes de la dinámica de la transmisión vectorial de los genotipos de T. cruzi en las diferentes regiones geográficas de distribución de la enfermedad de Chagas en Perú. Objetivo. Detectar y tipificar las unidades taxonómicas discretas de T. cruzi en las heces de siete especies de triatominos (Panstrongylus chinai, P. geniculatus, P. herreri, Rhodnius robustus, R. pictipes, Triatoma carrioni y T. infestans), capturados en ocho departamentos de diferentes regiones naturales de Perú. Materiales y métodos. Se examinaron 197 insectos para la detección de tripanosomas. Se extrajo el ADN del contenido intestinal de cada insecto y se amplificó mediante reacción en cadena de la polimerasa (PCR) de los genes kDNA, SL-IR, 24Sa rRNA y 18Sa RNA para detectar las DTU de T. cruzi. Resultados. Se detectaron cinco infecciones con T. rangeli y 113 con T. cruzi. De estas últimas, fue posible identificar 95 de TcI (dos en P. chinai, una en P. geniculatus, 68 en P. herreri, cuatro en R. pictipes, siete en R. robustus, una en T. carrioni, y 12 en T. infestans); cinco de TcII (cuatro en P. herreri, una en T. infestans); cuatro de TcIII (tres en P. herreri, una en R. robustus) y cuatro infecciones de TcIV en P. herreri. Conclusión. Este es el primer trabajo de caracterización a gran escala de T. cruzi en el intestino de vectores de importancia epidemiológica en Perú, orientado a generar información básica que permita entender la dinámica de la transmisión vectorial de T. cruzi en esta región del continente.

Abstract Introduction: Trypanosoma cruzi has been divided by international consensus into six discrete typing units (DTU): TcI, TcII, TcIII, TcIV, TcV y TcVI. The factors determining the dynamics of T. cruzi genotypes vector transmission of Chagas' disease in the different geographical regions of Perú are still unknown. Objective: To detect and type T. cruzi DTUs from the faeces of seven species of triatomines (Panstrongylus chinai, P. geniculatus, P. herreri, Rhodnius robustus, R. pictipes, Triatoma carrioni and T. infestans) captured in eight departments from different natural regions of Perú. Materials and methods: We examined 197 insects for detecting trypanosomes. DNA was extracted from each insect intestinal contents and PCR amplification of kDNA, SL-IR, 24Sa rRNA and 18Sa RNAwas performed for detecting T. cruzi DTUs. Results: Five T. rangeli and 113 T. cruzi infections were detected; 95 of the latter were identified as TcI (two in P. chinai, one in P. geniculatus, 68 in P. herreri, four in R. pictipes, seven in R. robustus, one in T. carrioni, 12 in T. infestans), five as TcII (four in P. herreri, one in T. infestans), four as TcIII (three in P. herreri, one in R. robustus) and four TcIV infections in P. herreri. Conclusions: This is the first study which has attempted a large-scale characterization of T. cruzi found in the intestine of epidemiologically important vectors in Perú, thus providing basic information that will facilitate a better understanding of the dynamics of T. cruzi vector transmission in Perú.

[Recurrent diarrhea due to Cystoisopora belli in HIV/AIDS patients receiving HAART]. / Diarrea recurrente por Cystoisopora belli en pacientes con infección por VIH con TARGA.

The Cystoisospora belli, before denominated as Isospora belli, is the etiologic agent of cystoisosoporiasis, an opportunistic infection affecting immunocompromised patients, characterized by chronic diarrhea and weight loss. The incidence of chronic diarrhea for this agent, in HIV patients, has decreased considerably. This thanks to the advent of highly active antiretroviral therapy (HAART), which has improved the patient's immune response and decrease viral load. We present six cases of cystoisosoporiasis recurrent and refractory to treatment in HIV patients, who was being treated with with trimethoprim / sulfamethoxazole (TMP / SMX) orally as a prophylaxis. Five of these patients passed away due to the infection, despite of the fact that they had a good response to HAART (adequate increase in CD4 and viral load undetectable) and they had been treated with second line drugs.

Diarrea recurrente por Cystoisopora belli en pacientes con infección por VIH con TARGA / Recurrent diarrhea due to Cystoisopora belli in HIV/AIDS patients receiving HAART

La Cystoisospora belli, antes denominada Isospora belli, es el agente etiológico de la cystoisosporiasis, una infección oportunista que afecta a pacientes inmunodeprimidos, caracterizada por diarrea crónica y pérdida ponderal. La incidencia de diarrea crónica por este agente, en pacientes infectados por el VIH, ha disminuido considerablemente. Ello gracias al advenimiento de la terapia antirretroviral de gran actividad (TARGA), con la que se ha logrado mejorar la respuesta inmunológica del paciente y disminuir su carga viral. Se presentan seis casos de cystoisosporiasis recurrente y refractaria en pacientes con infección por VIH, en quienes se diagnosticó cystoisosporiasis pese a que previamente se encontraban recibiendo profilaxis con trimetropin/sulfametoxazol (TMP/SMX). Cinco de ellos evolucionaron de manera tórpida y fallecieron, a pesar de una buena respuesta al TARGA (adecuado incremento de CD4 y disminución de la carga viral hasta rangos indetectables), y de tratamiento con TMP/SMX por vía oral y otros medicamentos de segunda línea.

The Cystoisospora belli, before denominated as Isospora belli, is the etiologic agent of cystoisosoporiasis, an opportunistic infection affecting immunocompromised patients, characterized by chronic diarrhea and weight loss. The incidence of chronic diarrhea for this agent, in HIV patients, has decreased considerably. This thanks to the advent of highly active antiretroviral therapy (HAART), which has improved the patient’s immune response and decrease viral load. We present six cases of cystoisosoporiasis recurrent and refractory to treatment in HIV patients, who was being treated with with trimethoprim / sulfamethoxazole (TMP / SMX) orally as a prophylaxis. Five of these patients passed away due to the infection, despite of the fact that they had a good response to HAART (adequate increase in CD4 and viral load undetectable) and they had been treated with second line drugs.

Comparación de tres pruebas serológicas para detectar infecciones por Paragonimus mexicanus en gatos infectados / Comparison of three serological tests to detect Paragonimus mexicanus infections in infected cats

Introducción: La paragonimiasis es una enfermedad pulmonar causada por tremátodes del género Paragonimus. Generalmente, el diagnóstico de laboratorio de la infección en humanos se realiza mediante la detección de huevos del parásito en esputo o heces; sin embargo, los resultados pueden ser negativos, necesitándose métodos diagnósticos alternativos. Objetivos: Comparar tres pruebas serológicas para la detección de anticuerpos contra el antígeno somático del estadio adulto de Paragonimus mexicanus (PmAS) en muestras de suero de gatos infectados experimentalmente. Diseño: Estudio experimental. Lugar: Bioterio del Instituto de Medicina Tropical ôDaniel A. Carriónõ de la Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Material biológico: Gatos domésticos de 4 a 6 meses de edad y antígeno somático crudo de P. mexicanus (PmAS). Intervenciones: Se obtuvo muestras de sangre de 12 gatos domésticos infectados experimentalmente con P. mexicanus. Los sueros fueron evaluados por el inmunoensayo enzimático (ELISA), la doble difusión (DD) y contrainmunoelectroforesis (CIEF). Principales medidas de resultados: Se determinó el porcentaje de gatos que revelaron resultados positivos de acuerdo a los criterios establecidos. Resultados: Se encontró una buena correlación entre los resultados obtenidos por ELISA y aquellos obtenidos por CIEF o DD. La CIEF y el ELISA fueron más sensibles que la doble difusión. Con la CIEF y el ELISA, 81,8 por ciento (9/11) y 75,0 por ciento (9/12) de los sueros evaluados dieron resultados positivos, respectivamente, mientras que 58,3 por ciento (7/12) de ellos fue positivo para la DD. Los sueros de 2 conejos con fasciolosis experimental dieron una reacción positiva con el antígeno PmAS por ELISA y CIEF. No se observó reacción cruzada cuando se usó sueros de gatos con dipilidiasis o de gatos sanos. Conclusiones: Estos resultados indican que la CIEF y el ELISA, que emplean antígeno somático crudo, son pruebas de similar sensibilidad para el diagnóstico de paragonimiosis, pero no pueden ser usadas para el diagnóstico diferencial de las infecciones por P. mexicanus y F. hepatica, debido a la ocurrencia de reacciones cruzadas.

Background: Paragonimiasis is a lung disease caused by Paragonimus trematodes genus. Human infection laboratory diagnosis is usually done by detection of parasite eggs in sputum or feces; however, findings may be negative and alternative diagnostic methods are required. Objectives: To compare three serologic tests for detection of Paragonimus mexicanus somatic antigen (PmAS) antibodies in serum samples of cats infected experimentally. Design: Experimental study. Setting: Instituto de Medicina Tropical ôDaniel A. Carriónõ bioterium, Faculty of Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru. Biologic material: Domestic cats 4-6 years old and P. mexicanus (PmAS) crude somatic antigen. Interventions: Blood samples were collected from twelve domestic cats infected with P. mexicanus. Serum samples were evaluated by enzyme-linked immunosorbent assay (ELISA), double diffusion (DD) and counterimmunoelectrophoresis (CIE). Results: Good correlation was found between ELISA results and those of CIE or DD. Both CIE and ELISA were more sensitive than DD. With CIE and ELISA sera were respectively positive 81.8 per cent (9/11) and 75.0 per cent (9/12), whereas 58.3 per cent (7/12) were positive for DD test. Sera from 2 rabbits with experimental fascioliosis had positive reaction with PmAS antigen by both ELISA and CIE tests. No cross-reactivity was observed using sera from cats with dipylidiasis or from healthy cats. Conclusions: Results showed that both ELISA and CIE were equally sensitive tests for paragonimiosis diagnosis but could not be used for differential diagnosis of P. mexicanus and F. hepatica infections due to cross-reaction.

Frequency of human toxocariasis in a rural population from Cajamarca, Peru determined by DOT-ELISA test.

The aim of this study was to estimate the frequency of human toxocariasis in Cauday district, Cajamarca, Peru, using a dot-ELISA test. From June to October 2005, a total of 256 adult subjects were studied. Blood samples were collected for serology by a dot-ELISA test and for hematological examination. Parasitological examination was also carried out in stool samples to check cross-reactions in the dot-ELISA. The frequency observed was 44.92%, with a significant higher proportion of positivity in male subjects. From subjects with positive serology, 45.6% had respiratory symptoms, 40.44% abdominal pain, 32.35% hepatic symptoms, 14.7% cutaneous signs, 13.23% ocular manifestations, 43.38% eosinophilia, and all of these were statistically associated to serology. Among the population evaluated, 90.23% (231/256) were parasitized. From subjects with positive serology, 92.17% had at least one intestinal parasite and the most frequent were: Blastocystis hominis (68.38%), Giardia lamblia (28.68%), Hymenolepis nana (20.0%), Ascaris lumbricoides (15.65%), Entamoeba histolytica/E. dispar (13.24%), Cyclospora cayetanensis (4.41%), Cryptosporidium sp. (1.47%), Enterobius vermicularis (0.87%), Strongyloides stercoralis (0.87%), Taenia sp. (0.87%), and Trichuris trichiura (0.87%). The rate of false positives in the dot-ELISA test was improved by serum absorption each with A. suum antigens, with a decrease of cross-reactions. In conclusion, human toxocariasis is highly frequent in this population and some risk factors like dog/cat ownership, presence of pets within house, and previous history of geophagia were observed in the present study.

Frequency of human toxocariasis in a rural population from Cajamarca, Peru determined by DOT-ELISA test / Freqüência de toxocaríase humana numa população rural de Cajamarca, Peru, mediante o uso do teste DOT-ELISA

The aim of this study was to estimate the frequency of human toxocariasis in Cauday district, Cajamarca, Peru, using a dot-ELISA test. From June to October 2005, a total of 256 adult subjects were studied. Blood samples were collected for serology by a dot-ELISA test and for hematological examination. Parasitological examination was also carried out in stool samples to check cross-reactions in the dot-ELISA. The frequency observed was 44.92%, with a significant higher proportion of positivity in male subjects. From subjects with positive serology, 45.6% had respiratory symptoms, 40.44% abdominal pain, 32.35% hepatic symptoms, 14.7% cutaneous signs, 13.23% ocular manifestations, 43.38% eosinophilia, and all of these were statistically associated to serology. Among the population evaluated, 90.23% (231/256) were parasitized. From subjects with positive serology, 92.17% had at least one intestinal parasite and the most frequent were: Blastocystis hominis (68.38%), Giardia lamblia (28.68%), Hymenolepis nana (20.0%), Ascaris lumbricoides (15.65%), Entamoeba histolytica/E. dispar (13.24%), Cyclospora cayetanensis (4.41%), Cryptosporidium sp. (1.47%), Enterobius vermicularis (0.87%), Strongyloides stercoralis (0.87%), Taenia sp. (0.87%), and Trichuris trichiura (0.87%). The rate of false positives in the dot-ELISA test was improved by serum absorption each with A. suum antigens, with a decrease of cross-reactions. In conclusion, human toxocariasis is highly frequent in this population and some risk factors like dog/cat ownership, presence of pets within house, and previous history of geophagia were observed in the present study.

O propósito do presente estudo foi estimar a freqüência da toxocaríase no distrito de Cauday, Cajamarca, Peru, usando o dot-ELISA teste. Entre junho e outubro de 2005, um total de 256 pessoas foram avaliadas. Coletaram-se amostras de sangue para o teste de dot-ELISA e para o exame hematológico e amostras de fezes para exame parasitológico. A freqüência geral de anticorpos anti-Toxocara observada foi de 44,92%, com maior proporção significativa de positividade em pessoas do sexo masculino. Das pessoas com sorologia positiva, 45,6% apresentavam sintomas respiratórios, 40,44% dores abdominais, 32,35% moléstias hepáticas, 14,7% sinais cutâneos, 13,23% manifestações oculares, 43,38% eosinofilia e todos estes fatores foram estatisticamente associados à sorologia. Entre as pessoas avaliadas 90,23% estavam parasitadas e 92,17% das pessoas com sorologia positiva tinham algum parasito intestinal, sendo os mais freqüentes: Blastocystis hominis (68,38%), Giardia lamblia (28,68%), Hymenolepis nana (20,0%), Ascaris lumbricoides (15,65%), Entamoeba histolytica/E. dispar (13,24%), Cyclospora cayetanensis (4,41%), Cryptosporidium sp. (1,47%), Enterobius vermicularis (0,87%), Strongyloides stercoralis (0,87%), Taenia sp. (0,87%) e Trichuris trichiura (0,87%). A taxa de falsos positivos no teste dot-ELISA foi melhorada pela absorção dos soros com antígenos de A. suum, com diminuição das reações cruzadas. Em conclusão, a toxocaríase humana é altamente freqüente nesta população e fatores de risco como ter um cão/gato, presença dos animais dentro de casa e estória prévia de geofagia foram observados durante o presente estudo.

Paragonimosis in the Cajabamba and Condebamba districts, Cajamarca, Peru

Stool samples from 409 pre-school and school students, living in six villages of the Cajabamba and Condebamba districts, Cajamarca, Perú, were examined using wet preparations and Lumbreras' method, looking for Paragonimus eggs. Fecal and sputum samples from two children (0.5 percent) of 6 and 8 year-old showed eggs of Paragonimus. One hundred and twenty freshwater crabs, Hypolobocera chilensis eigenmanni, were collected from the Condebamba valley and 21 (17.5 percent) of them were infected with P. mexicanus (syn. P. peruvianus) metacercariae. Our results show the persistence of Paragonimus in human beings and in the main source of infection, the crabs

La Paragonimosis en escolares del Valle de Condebamba, Cajamarca - Perú / Paragonimiasis in School children from Condebamba Valley, Cajamarca-Perú

Objetivo: Estudiar la prevalencia de paragominiosis en escolares de educación primaria de tres localidades del valle de Condebamba, Departamento de Cajamarca. Materiales y métodos: Se utilizó el examen de heces, la intradermorreacción y contrainmunoelectroforesis a quienes tuvieron esta última prueba positiva. Resultados: De las 77 intradermorreacciones practicadas 2 fueron positivas (2,6 por ciento), las cuales tyambién fueron positivas por contrainmunoelectroforesis. Todas las 77 muestras de heces examinadas fueron negativas para huevos de Paragonimus. Conclusión: Estpos resultados muestra una declinación de los caoss de paragominosis humana en el valle de Condebamba.

Prevalencia de E. histolytica y E. dispar por microscopía y ELISA en muestras fecales de una población urbano marginal de Lima / Pevalence of E. histolytica and E. dispar by means microscopy and ELISA in a sub urban of Lima

El propósito del presente estudio fue utilizar pruebas inmunoenzimáticas (ELISA) para estudiar la prevalencia de Entamoeba histolytica y Entamoeba dispar en una localidad urbano marginal de Lima( Callao). Se utilizaron dos ELISA: uno que detecta E. histolytica. Se obtuvieron aleatoriamente 128 muestras de heces, de las cuales 13 (10 por ciento) fueron positivas por microscopia a E. histolytica o E. dispar (ELISA Entamoeba), y otro que identifia especificamente a E. hystolicatica. Se obtuvieron aleatoriamaente 128 muestras de heces de las cuakles 13 (10 por ciento) fueron positivas por microscopía a E. histolytica o E. dispar, siendo sólo 7 positivas por ELISA - Entamoeba (Especificidad = 96 por ciento). No se detecto E. histolytica enla población estudiada. No hubo una buena correlación entre la identificaciín microscoópica y la prueba de ELISA que identifica E. histolytica o E. dispar, probablemente debido a una sobreestimación en la identificación morfológica.

La paragonimosis en escolares del Valle de Condebamba, Cajamarca, Perú / Paragonimosis in school children from Condebamba valley, Cajamarca, Perú

Se realizó un estudio de la prevalencia de parafonimosis en escolares de educación primaria de tres localidades del valle de Condebamba, Departamento de Cajamarca, utilizando la intradermorreacción y el examen de heces. De las 77 intradermorreacciones practicadas 2 fueron positivas (2,6 por ciento), las cuales también fueron positivas por contrainmunoelectroforesis. Todas las 77 muestras de heces examinadas fueron negativas a huevos de paragonimus. Estos resultados muestran una declinación de casos de paragonimosis humana en el valle de Condebamba