 Some strains of M-CoV cause a progressive demyelinating encephalitis in mice which has been used as a murine model for multiple sclerosis.Significant research efforts have been focused on elucidating the viral pathogenesis of these animal coronaviruses, especially by virologists interested in veterinary and zoonotic diseases.A feature of the MHV is that many strains have the hemagglutinin-esterase gene turned into a pseudogene.