Experimentally Induced Cerebral Cystic Echinococcosis in Rats: A Suitable Animal Model for Cerebral Echinococcosis

Abstract

Background: Echinococcus granulosus is a worldwide zoonotic cestode that lives mainly in the intestine of dog as definitive host. Its larval stage infects intermediate hosts and forms hydatid cysts mainly in the liver and lungs tissues and less other organs such as brain, eye and bone. In the experimental models, inoculation of protoscoleces into the peritoneum, thoracic cavity, subcutaneous and cerebrum produces hydatid cysts. Experimental echinococcosis in the animal models provides a good opportunity for study of the parasite-host relationship, different transmission ways of infection in the intermediate hosts and effect of new drugs.

Methods: The present study was conducted in the Veterinary School, Shahid Bahonar University of Kerman, Kerman, Iran in 2018. In this study, cerebral hydatidosis was investigated in 6 female Wistar rats weighing (200±20 gr). For this purpose, protoscoleces were collected from hydatid cysts of infected sheep liver. Overall, 300 protoscolices were injected directly in the lateral ventricle by an insulin syringe through the implanted cannula.

Results: After 4 months of inoculation, multiple thin-walled, transparent hydatid cysts were observed in the rat skull. All cysts were infertile. The cysts were localized prominently on the cerebral cortex and lesser in the parenchyma and ventricles. The cyst walls consisted of three layers consist of the outer layer (fibrous capsule), two parasitic layers and the endocyst layer (germinal layer). The cyst was surrounded by the inflammatory cells consist of lymphocytes, plasma cells and macrophages.

Conclusion: To the best of our knowledge, this research is the first experimental cerebral hydatidosis arisen from larval stage of Echinococcus granulosus in the animal model.