Staggering disease in cats: isolation and characterization of the feline Borna disease virus.

A Borna disease virus (BDV)-like agent was isolated from the central nervous system (CNS) of cats with a spontaneous non-suppurative encephalomyelitis ('staggering disease'). In contrast to the rabbit-adapted BDV strain V, which can be propagated in several primary and permanent cell cultures, the cat virus grew only in embryonic mink brain cells. Infection of adult Wistar rats with feline brain tissue material did not result in clinical disease during a period of 5 months, nor in growth of infectious virus in the brain. However, using the brain suspension of a newborn rat inoculated with feline brain tissue material, it was possible to induce typical Borna disease (BD) in four adult rats. This indicates a possible adaptation of the cat virus during passages in rats. By the use of an RT-PCR technique, BDV-specific RNA could be detected in a majority of brain samples from diseased cats. BDV-specific antigen was demonstrated in feline CNS samples both by immunohistochemistry and ELISA. However, the amount of BDV RNA and BDV antigen was less in the cats as compared to horses with BD, providing further support for the notion that a distinct feline BDV strain exists.

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.

Borna disease virus infection and affective disorders in man.

Borna Disease virus (BDV) can persistently infect the central nervous system of a broad spectrum of animal species. The clinical course varies from slight behavioral disturbances to a fatal neurological syndrome. In-vivo diagnosis is based on the strong humoral immune response to BDV antigens. Since also human infections could be confirmed by specific antibodies and increased seroprevalence was found in patients with chronic neurologic or immunologic disorders, the contribution of BDV or a BDV-like human variant to syndromes with yet unknown etiology became of great interest. We presented the first data of a current follow-up study on 70 psychiatric patients who were tested three times each after hospitalization. In contrast to previously found low prevalence of antibody carriers by screening (2-4%), we now found 20% positives by follow-up testing. Furthermore, of the randomly selected patients with different psychiatric diagnosis, the highest proportion of antibody carriers was detected among patients with major depression (more than 30%), compared to only 8% among patients with dysthymia (neurotic depression). This led us to hypothesize that Bornavirus infection might contribute somehow to the syndrome of major depressive illness by altering neuronal cells in the limbic system.