The lysogenic bacteriophage MAV1 has been shown to be a virulence factor for the development of arthritis in rats infected with Mycoplasma arthritidis. In the present study, arthritis was evaluated by histopathologic examination to demonstrate that MAV1 is a virulence factor not only in the rat but also in the mouse. Specifically, the MAV1 lysogen 158L3-1 was more virulent than the nonlysogen strain 158 in DBA/2NCr, C3H/HeNCr, C3H/HeJ, and C3Smn. CB17-Prkdcscid/J mice, as well as in LEW rats.
