Polyarthritis's any type of arthritis which involves five or more joints — an inflammation of two, three or four joints's an oligoarthritis. Polyarthritis may be experienced at any age and isn't gender specific. Causes Polyarthritis's most often caused by an auto-immune disorder such as Rheumatoid arthritis, Psoriatic arthritis, and Lupus erythematosus but can also be caused by infection with an alphavirus such as Chikungunya Virus and Ross River Virus. This condition's termed Alphavirus… (More on Polyarthritis)