Development of Taenia pisiformis in golden hamster (Mesocricetus auratus).

The life cycle of Taenia pisiformis includes canines as definitive hosts and rabbits as intermediate hosts. Golden hamster (Mesocricetus auratus) is a rodent that has been successfully used as experimental model of Taenia solium taeniosis. In the present study we describe the course of T. pisiformis infection in experimentally infected golden hamsters. Ten females, treated with methyl-prednisolone acetate were infected with three T. pisiformis cysticerci each one excised from one rabbit. Proglottids released in faeces and adults recovered during necropsy showed that all animals were infected. Eggs obtained from the hamsters' tapeworms, were assessed for viability using trypan blue or propidium iodide stains. Afterwards, some rabbits were inoculated with eggs, necropsy was performed after seven weeks and viable cysticerci were obtained. Our results demonstrate that the experimental model of adult Taenia pisiformis in golden hamster can replace the use of canines in order to study this parasite and to provide eggs and adult tapeworms to be used in different types of experiments.

Chinchilla laniger can be used as an experimental model for Taenia solium taeniasis.

Chinchilla laniger has been reported as an experimental definitive host for Taenia solium; however no information about its suitability and yield of gravid tapeworm proglottids containing viable and infective eggs has been published. In total 55 outbred female chinchillas were infected with 4 cysticerci each; hosts were immunodeppressed with 6 or 8 mg of methyl-prednisolone acetate every 14 days starting the day of infection and their discomfort was followed. Kinetics of coproantigen ELISA or expelled proglottids was used to define the infection status. Efficiency of tapeworm establishment was 21% and of parasite gravidity was 8%; chinchillas showed some degree of suffering along the infection. Viability of eggs obtained from gravid proglottids was tested comparing methods previously published, our results showed 62% viability with propidium iodide, 54% with trypan blue, 34% with neutral red, 30% by oncosphere activation and 7% with bromide 3-(4,5-dimetil-tiazol-2-il)-2,5-difenil-tetrazolio (MTT) reduction; no statistical differences were obtained between most techniques, except activation. Four piglets were infected with 50,000 eggs each, necropsy was performed 3 months later and, after counting the number of cysticerci recovered, the percentage of infection was similar to data obtained with T. solium eggs recovered from humans. Our results demonstrate that the experimental model of T. solium taeniasis in C. laniger is a good alternative for providing eggs and adult tapeworms to be used in different types of experiments; optimization of the model probably depends on the use of inbred hosts and on the reduction of infected animals' suffering.

Efecto de una plastia circular en el cuello de la vejiga paralítica experimental / Effect of circular plasty in the experimental paralitic bladder neck

Introducción. La incontinencia urinaria es un problema grave que demanda medidas terapéuticas de acuerdo a su grado y etiología. En la llamada vejiga neurógena por ser consecutiva a lesiones nerviosas, se han utilizado diversos métodos para su control, tales como: medicamentos, cateterismo uretral, colectores, esfínteres artificiales e intervenciones quirúrgicas en cuello, pared vesical y derivación permanente de vías urinarias. Material y métodos. En este trabajo se presenta un modelo experimental de plastia circular en 55 conejos machos, en los cuales se produjo una vejiga paralítica por sección medular en la que se realizó una plastia, no descrita, por plegamiento del cuello con suturas de pespunte vertical y transversal en todo su rededor, respetando la desembocadura de ureteros y conductos espermáticos. Resultados. Evaluada por cistometría en la etapa previa al procedimiento, la vejiga tuvo una capacidad media de 37 mL, con presión de salida de 28 cm; en la fase paralítica la capacidad fue de 200 mL y la presión de 28 cm; después de la plastia tuvo 61 mL de capacidad y 27 cm de presión de salida. Conclusión. El resultado de la plastia fue satisfactorio porque la incontinencia presente en la fase paralítica no existió después de la plastia