Persistent shedding of mouse hepatitis virus in mouse lines selected for genetic differences in alcohol sensitivity

Two replicate lines of mice, selected for hyperactivity and hypoactivity after ethanol administration, had been enzootically infected with mouse hepatitis virus (MHV) for over a decade. A cessation of breeding program (also known as a "burnout") was implemented to eradicate the virus and was successful in only one of the four lines. Subsequent investigation demonstrated persistent shedding of MHV in two lines of mice for at least 7 weeks. To the author's knowledge, this is the first documented case of clinically inapparent persistent shedding of MHV in mice that are not genetically engineered.