Mycoplasmosis in free-ranging desert tortoises in Utah and Arizona.

Upper respiratory tract disease (URTD) has been associated with major losses of free-ranging desert tortoises (Gopherus agassizii) in the southwestern United States. This prompted a clinical examination of 63 free-ranging desert tortoises for signs of URTD and sampling for Mycoplasma agassizii, the causative agent of URTD. Tortoises were sampled from three sites in the eastern Mojave Desert (1992-93), and from three sites in the Sonoran Desert (1992-94).