Alterações iniciais da fibrose septal por Capillaria Hepatica (Bancroft, 1893) em ratos / Initial changes of septal fibrosis Capillaria hepatica (Bancroft, 1893) in rats

espaço-porta é o local de origem da fibrose em muitas doenças crônicas hepáticas. Essa área do fígado participa da drenagem linfática hepática e abriga diversos elementos celulares potencialmente fibrogênicos. Estudos sobre a fibrose hepática relacionados à infecção experimental de ratos pelo helminto Capillaria hepatica têm demonstrado que a fibrose começa em áreas portais com a distribuição de septos que sulcam o parênquima hepático se desenvolvendo em áreas próximas ao espaço de Disse. Entretanto, apesar de esta fibrose ocorrer de forma paralela aos sinusóides, estudos têm revelado que não apenas as células estreladas hepáticas participam da fibrose septal, mas também outros tipos celulares residentes nos espaços-porta. Diante destes aspectos, o presente estudo desenvolveu-se com o intuito de investigar a contribuição das células potencialmente fibrogênicas dos espaços-porta, nas fases iniciais da infecção, onde a fibrose se concentra. Para isso, foram utilizados fragmentos de fígado, em blocos parafinados, disponíveis nos arquivos do Laboratório de Patologia Experimental (CPqGM/Fiocruz) provenientes de ratos infectados com 800 ovos de Capillaria hepatica e foi possível observar que ocorreu a proliferação de colangiócitos e a concentração de miofibroblastos em áreas portais, além da ativação de células estreladas hepáticas, sendo todos os resultados vistos por meio da coloração de rotina HE, Picro-sírius vermelho e imunohistoquímica para α-actina de músculo liso, CD31 e GFAP.

Portal space is the local of origin for fibrosis in many chronic liver diseases. This area is involved with lymph drainage and contains several cell types, potentially fibrogenic. Experimental studies related to hepatic fibrosis during Capillaria hepatica infection in rats have suggested that the septal fibrosis indeed takes origin from portal spaces, with the distribution of the septs in the parenchymal region in proximity areas of Disse space. However, despite this fibrosis occurs in parallel to sinusoids, studies have revealed that not only the hepatic stellate cells participate in septal fibrosis, but also other resident cell types in the portal spaces. In face these aspects, the goal of present study was investigate the contribution of the cells potentially fibrogenic in the portal space, in the early phases of the infection. For this, blocks in paraffin available of the liver of rats infected with 800 eggs of Capillaria hepatica archived in the Laboratory of Experimental Pathology (Research Center Gonçalo Moniz, Fiocruz - BA), were utilized and it was observed that proliferation of colangiocytes and concentration of myofibroblasts occurred portal areas, in addition to the activation of hepatic stellate cells. All results were analised by routine staining HE, Sirius red and immunohistochemistry for α-SMA, GFAP and CD31.

Rattus norvegicus como indicador de la circulación de Capillaria hepatica y Taenia taeniaeformis en la Plaza Minorista de Medellín, Colombia / Rattus norvegicus as an indicator of circulation of Capillaria hepatica and Taenia taeniaeformis on a groceries trade center of Medellín, Colombia

Introducción. Rattus norvegicus cumple un papel epidemiológico en el mantenimiento y dispersión de agentes zoonóticos bacterianos, virales y parasitarios de interés en salud pública. La presencia de infección por helmintos en especies Rattus cercanas a poblaciones expuestas en condiciones ambientales propicias, puede convertirse en un factor de riesgo de transmisión. Objetivo. Reportar la frecuencia de infección con Capillaria hepatica y formas larvarias de Taenia taeniaeformis en ratas silvestres (R. norvegicus) capturadas en una zona urbana de Medellín. Materiales y métodos. Se capturaron 254 ejemplares de R. norvegicus. Los hígados de 54 ejemplares que presentaron lesión hepática macroscópica durante la necropsia, fueron examinados por histopatología convencional. Resultados. La frecuencia de infección por C. hepatica fue de 20,1 % (51/254). Seis hígados fueron también positivos para larvas de T. taeniaeformis con una frecuencia de 2,4 % (6/254). Los hígados infestados con C. hepatica exhibían parásitos en el estadio adulto o juvenil y huevos ovalados con opérculos bipolares, asociados con hepatitis granulomatosa leve a moderada multifocal y acompañada por infiltrado leucocitario. Se observaron lesiones granulomatosas en resolución y fibrosis residual o calcificada que contenía huevos. Donde se encontraron cisticercos de T. taeniaeformis, el hallazgo más frecuente fueron quistes hepáticos que contenían larvas, y lesiones inflamatorias y fibróticas. Conclusión. Estos resultados indican que helmintos de potencial zoonótico circulan en R. norvegicus de ambientes urbanos. Debe investigarse la verdadera distribución de estos parásitos, para determinar el riesgo potencial que corren las poblaciones animales y humanas expuestas a adquirir este tipo de infecciones.

Introduction. Rattus norvegicus, the Norway rat, plays a pivotal role in the maintenance and spread of several zoonotic bacterial, viral and parasitic pathogens of public health interest. The presence of helminthic infections near susceptible human populations can, under appropriate environmental conditions, become a risk factor for their transmission. Objective. Frequencies of infection were reported for Capillaria hepatica and larval forms of Taenia taeniaeformis in wild rats (R. norvegicus) captured in an urban area. Materials and methods. Two hundred and fifty-four adult specimens of R. norvegicus were collected in an urban zone of Medellín, Colombia. The livers of 54 specimens that showed macroscopic hepatic lesions during necropsy were examined by conventional histopathology. Results. The frequency of infestation with C. hepatica was 20.1% (51/254). Six livers (2.4%) were also positive for larvae of T. taeniaeformis. Livers infested with C. hepatica exhibited adult or juvenile parasites and oval eggs with bipolar opercula, and were associated with mild to moderate multifocal granulomatous hepatitis with leucocyte infiltrate. Granulomatous lesions and calcified residual fibroses were found with eggs but without adult parasites. Those animals with cysticerci of T. taeniaeformis showed a high frequency of hepatic cysts containing larvae as well as inflammed and fibrotic lesions. Conclusion. Zoonotic helminths circulate at high frequency in R. norvegicus that occur in urban environments. Further research about the distribution of these parasites will determine the level of health threat they present for susceptible human and domestic animal populations.

Capillariasis philippinensis: a fish-borne parasitic zoonosis.

Fish from lagoons in Northern Luzon, Philippines, have been shown experimentally to be intermediate hosts of Capillaria philippinensis. Eggs ingested by the fish hatch in the intestines and the larvae double in size in 3 weeks. When fed to monkeys, Mongolian gerbils and birds, the larvae develop into adults and reproduce. Fish from the lagoons or purchased from the market were fed to gerbils and the animals developed patent infections, demonstrating natural transmission of the parasite. Philippine and Thailand populations have the habit of eating uncooked freshwater and brackish water fish and some have been experimentally infected with C. philippinensis. These countries report the largest number of cases of intestinal capillariasis. Fish-eating birds are now considered natural hosts for the parasite, fish the intermediate hosts, and humans accidentally become infected by eating infected fish.