Shaggy Lame Fox Syndrome in Pribilof Island Arctic Foxes ( Alopex lagopus pribilofensis), Alaska

A previously unrecognized condition is described in wild free-ranging Pribilof arctic foxes ( Alopex lagopus pribilofensis) from the Pribilof Islands, Alaska, USA. This condition is called shaggy lame fox syndrome (SLFS) denoting the primary clinical signs first observed. Criteria used to suspect SLFS on gross examination included emaciation, failure to shed winter pelage and moderate to severe polyarthritis. Criteria used to confirm SLFS histologically included polyarthritis (characterized by lymphoplasmacytic synovitis, tenosynovitis, bursitis, periosteal bony proliferation, and periarticular lymphoplasmacytic vasculitis) and systemic leukocytoclastic vasculitis. Other histological lesions often found included renal cortical infarcts, myocarditis with myocardial infarcts, lymphoplasmacytic meningitis, lymphoplasmacytic cuffing of meningeal and a few cerebral vessels, and cavitating infarcts of the brainstem and thalamus. The cause of SLFS is not known at this time; however, the gross and histological lesions suggest that the cause of SLFS may be a bacterial polyarthritis with a secondary immune-mediated vasculitis. These lesions are consistent with changes described with Erysipelothrix rhusiopathiae in domestic dogs; E. rhusiopathiae was identified from the synovial membrane of a swollen stifle joint and the kidney from one fox using real-time polymerase chain reaction and with culture from a fox that had gross and histological lesions of SLFS. Therefore, E. rhusiopathiae is a possible etiological agent for SLFS.