In males, the infection can cause acute orchitis and epididymitis, and in turn infertility. Up to 20% of cases can have genitourinary involvement; orchitis and epididymitis are most common. Other risk factors include inguinal hernias, Klinefelter syndrome, and mumps orchitis. Injection of sperm antigens causes inflammation of the testis (auto-immune orchitis) and reduced fertility. To study orchitis in the testis, autoimmune orchitis has been induced in the rodent testis. Symptoms of orchitis are similar to those of testicular torsion. It is much more common than testicular inflammation, termed orchitis. It can also cause orchitis in men, and meningitis, pancreatitis, and deafness in some cases. Autoimmune orchitis is rare in humans, compared to anti-sperm antibodies. Orchitis is also common in men. Orchitis is not rare in bulls and rams. Orchitis can also be seen during active mumps, particularly in adolescent boys. Orchitis is a condition of testicular pain involving swelling, inflammation and possibly infection.