Etiology and Epidemiology of Verminous Encephalitis in an Emu

Abstract

Verminous encephalitis was reported in 1978 in an emu (Dromaius novaehollandiae) from Indiana (8). The bird was the second of two emus that had developed severe ataxia followed by bilateral leg paralysis, which resulted in natural death of the first bird. The second emu was presented alive but unable to stand to the Purdue Animal Disease Diagnostic Laboratory. No gross lesions were found, but on histologic examination, focal malacic lesions and inflammatory changes were seen in the cerebellum, in association with an ascarid larva. No generic or specific identification of the parasite was made, nor was information presented concerning the possible source or mode of infection of the birds. Of the four other known outbreaks or cases of cerebrospinal nematodiasis in avian species (1,3,4,5), the two most extensive were positively linked to migrating larvae of Baylisascaris procyonis, the common roundworm of raccoons (3,4). In one of these, 622 chickens died following a single exposure to contaminated bedding (4), and in the other, all 85 quail died following exposure to a contaminated run (3). A third case involved central nervous system (CNS) disease in a chukar partridge; B. procyonis was suggested as the cause (5). In the fourth case, no identification was made of the ascarid species responsible for CNS disease in tumbler pigeons (1). The present report is based on a retrospective evaluation of a case of verminous encephalitis in an emu (8). New information is presented concerning the etiology and epidemiology of the parasite involved. Examination of sections of cerebellum revealed an ascarid larva within a focus of reactive malacia. The larva had prominent