Experimental intravitreous cysticercosis

Background: Cysticercosis is one of the parasitic diseases that most frequently affects the eye. The most common and severe manifestations of ocular infection are secondary to posterior segment involvement, which often leads to blindness and atrophy of the eye. The pathogenesis of ocular injury in this disease is poorly understood. The authors have developed an experimental animal model for intravitreous cysticercosis using New Zealand rabbits and Taenia crassiceps cysticerci. Methods: Twelve rabbits were divided into two groups. Rabbits in group I were inoculated with one living cysticercus in the vitreous cavity. Rabbits in group II received an intramuscular dose of steroids prior to inoculation of parasites Results: An intense inflammatory reaction, which lead to a severe ocular injury, was observed in rabbits of group I, while rabbits in group II had minimal inflammatory changes. Histopathological studies showed a severe histiocytic infiltrate with generalized retinal damage in group I, and a mild inflammatory infiltrate, limited to the area of direct contact with the parasite in group II. The ocular lesions found in rabbits which did not receive steroids (group I) resembled those found in human ocular cysticercosis. Conclusion: These observations indicate that ocular damage in this parasitic disease might be directly related to inflammatory changes produced by the presence of cysticerci. This model appears to be useful for future investigations