Mycoplasmosis: experimental and spontaneous infections of the genital tract of bulls.

A strain of M. bovigenitalium was isolated from semen of a bull (K) with chronic seminal vesiculitis. Using this strain a vesiculitis of the same type as found in bull K, characterized by simultaneous acute and chronic lesions, was induced experimentally in 2 bulls by direct inoculation into the vesicular glands. In the acute phase a marked infiltration of eosinophils was found in the interstitial tissues and alveoli whereas in the chronic phase fibrosis, lymphoid and epithelial hyperplasia were seen. Degeneration of vascular walls and connective tissue was common. On inoculation into the testis of 3 bulls a chronic epididymitis and ampullitis were produced. The histological changes were of the same type as found in the vesicular glands of the 3 bulls with vesiculitis. By indirect hemagglutination a specific and significant increase in serum antibody could be demonstrated. As the titers were low and the maximum titers were reached early, it will probably not often be possible to make an etiological diagnosis on the basis of serological evidence. A comparative experiment employing the type strain (PG 11) of M. bovigenitalium was performed. A rise in antibody titer was seen, but neither clinical nor histological changes could be demonstrated.