Feline encephalomyelitis

Infectious diseases of the central nervous system

Neurologic disease is seen commonly in cats, with infectious causes accounting for 30-45% of cases. However, since a specific infection cannot be identified in 12-40% of these cases, it is essential that we try to understand these cases better in the hope that we can eventually identify the cause(s), and so determine how best to treat and/or prevent them.

High prevalence of Borna disease virus in domestic cats with neurological disorders in Japan

A total of 15 (T-1-T-15) domestic cats with neurological disorders in Tokyo area were examined for association with Borna disease virus (BDV). None had detectable antibodies to feline immunodeficiency virus (FIV), feline leukemia virus, feline infectious peritonitis virus and Toxoplasma gondii, and only cat T-8 had detectable antibody to FIV. Serological and molecular epidemiological studies revealed a significantly high prevalence of BDV infection in these cats: antibodies against BDV p24 and/or p40 proteins in 10/15 (66.7%) and p24 and/or p40 RNA in peripheral blood mononuclear cells in 8/15 (53.3%). Further, in situ hybridization and immunohistochemistry analyses of the autopsied brain samples derived from one of the cats (T-15) revealed BDV RNA predominantly in neuronal cells in restricted regions, such as olfactory bulb and medulla of cerebrum. Thus, BDV is present in Japanese domestic cats with neurological disorders at a high prevalence.

Description of feline nonsuppurative meningoencephalomyelitis ("staggering disease") and studies of its etiology

A spontaneous neurological disease in domestic cats is described. The clinical signs included staggering gait, hind limb ataxia, and paresis. Histologically, a nonsuppurative meningoencephalomyelitis with a characteristic distribution pattern was found, indicating a viral etiology. In serum samples from diseased cats, antibodies to Borna disease virus were demonstrated.

Encephalomyelopathy in young cats

Nineteen cats, aged three to 16 months, developed neurological signs including hindleg paralysis, head shaking, nystagmus, defective vision and reduced proprioception. Most of the animals were in cat colonies in research centres and were derived from specific pathogen-free stock. One was referred from veterinary practice. Over 40 per cent of litters could be affected constituting a serious commercial loss. Wallerian degeneration affected long tracts in the spinal cord and variously in the brain stem and cerebral white matter. In seven animals there was loss of Purkinje cells in the cerebellum and in eight there was neuronal loss in the spinal cord. Gliosis accompanied all changes. Although no viral agent was isolated the clinical pattern of the disease and evidence from other cases reported in the literature suggest an infectious cause.

Natural Borna disease in domestic animals others than horses and sheep

In 24 cats (Uppsala, Sweden) with neurological signs of "staggering disease" and typical neuropathology, 44% had Borna disease virus (BDV)-specific antibodies. In 173 cat sera (Berlin, Germany) of animals with unknown record, 7% were BDV positive. Out of 24 cats with undefined neurological disorders, 13% were BDV positive. Similarities in staggering disease of cats and Borna disease of horses and sheep suggest related etiological agents.

Feline non-suppurative meningoencephalomyelitis. A clinical and pathological study

A spontaneous neurological disease in cats characterized by behavioural and motor disturbances was investigated by clinical, morphological and immunological methods. Neuropathological examination showed a marked inflammatory reaction in the cerebral leptomeninges and the grey matter of the brain. In the white matter, the reaction was moderate. The changes consisted of perivascular cuffing by mononuclear cells and neuronal damage. The brain stem (thalamus, mesencephalon, caudal colliculus) was most severely affected. The spinal cord and its leptomeninges were involved to a lesser degree. The histopathological picture as well as the laboratory findings suggests a viral cause of the disease. The morphology of the disease and serological as well as immunohistochemical results indicate that this disorder is different from previously known feline viral encephalitides.

Primary demyelination in the central nervous system of cats

Primary demyelinating lesions have been observed in the central nervous system of 16 (approximately 7%) of a total of 235 clinically normal cats. The size of the lesions varied from small perivascular lesions in white matter to a large lesion occupying the diameter of an optic nerve. Intracytoplasmic inclusions consisting of tubular structures were common to all lesions examined by electron microscopy. The features of these feline lesions are briefly compared with those seen in multiple sclerosis.

Multiple sclerosis: is the domestic cat involved?

Recent evidence suggests a possible viral aetiology of multiple sclerosis (MS). The present hypothesis proposes a relationship between MS and a demyelinating condition in the central nervous system of cats from which a paramyxovirus has been isolated. The theory attempts to relate the distribution and incidence of MS with the keeping of cats as household pets. The incidence of MS is explained on the basis of a human susceptibility factor, perhaps the histocompatibility antigens and the onset, remissions and relapse of MS are considered to be related to stressful situations which trigger a persistent virus.

Observations on focal demyelinating lesions in cat optic nerves

A demyelinating perivascular condition has been observed in the optic nerves of three cats, the lesions of which included the following features: thinly myelinated and demyelinated axons, few normal oligodendrocytes, astroglial scar tissue, lymphocytes, plasma cells, mononuclear phagocytic cells and lipid-laden cells. Also present were tubular inclusion bodies which had morphological features similar to the nucleocapsids of some paramyxoviruses. These lesions are compared with some other demyelinating diseases of the central nervous system, and similarities to the lesions of multiple sclerosis are suggested.