Rheumatoid Arthritis

Rheumatoid arthritis is a very common autoimmune disorder of humans estimated to affect >1% of the human population, characterized by swelling and synovial inflammation of peripheral joints, with a positive serum rheumatoid factor. The disease progresses as the person ages resulting in severe deformities of the joints. This condition has not been reported in most captive great apes, but  has been reported in lowland gorillas housed in zoo environments, along with positive rheumatoid factor. Synovial biopsy in these cases showed very mild synovial lining proliferation with edema and focal nodular lymphocytic infiltrate around some synovial capillary blood vessels, not as exuberant as that often seen in human disease.  Overall, the incidence in great apes appears to be rare compared with that of humans