Chronic disease in the Mojave desert tortoise: Host physiology and recrudescence obscure patterns of pathogen transmission.

A seminatural, factorial-design experiment was used to quantify dynamics of the pathogen and upper respiratory tract disease in the Mojave desert tortoise () over 2 years. Groups of initially healthy animals were separated into serologically positive (seropositive), seronegative, and artificially infected groups and paired into 23 pens. We found no evidence of long-term immune protection to or of immunological memory.