JHM Infections in Rats As a Model for Acute and Subacute Demyelinating Disease

An animal model with different central nervous system (CNS) disease processes associated with demyelination is described which provides a basis to analyse the pathogenetic mechanisms leading to these disorders. Intracerebral infection of rats with the murine coronavirus strain JHM can result in an acute encephalomyelitis with a short incubation period or in subacute to chronic encephalomyelitis occurring after prolonged incubation. The most prominent finding of the latter two diseases consists of typical demyelinated lesions distributed in selected areas of the CNS. The induction of high rates of animals with demyelination depends both on properties of the virus used for infection and host factors such as age and immune status. A high number of rats with demyelination was obtained by intracerebral inoculation of temperature sensitive mutants into suckling rats with maternal JHM antibodies.