An epizootic of cerebral nematodiasis in rabbits due to Ascaris columnarus.

An epizootic of cerebral nematodiasis due to ascaris columnaris occurred in a commercial rabbitry, and 80 diseased rabbits died or were killed. The morbidity was high in groups of recently purchased rabbits and in the offspring of 12 breeder rabbits. The breeder rabbits which had been on the farm for more than a yr survived the outbreaks. Wild animals and birds had access to the facilities, but raccoons and skunks were never observed. A columnaris larvae were found on histopathologic examination. and live larvae were recovered from brains of 2 diseased rabbits.