Number 09 is a friendly 18 year old bighorn sheep ewe in the Lostine population. She has been chronically infected with Mycoplasma ovipneumoniae for the duration of our three year study. However, not all infected animals have snotty noses. Most infected animals appear healthy and have an excellent survival rate, but lambs infected by these asymptomatic carriers succumb to pneumonia with very high mortality rates. It is the lamb mortality and subsequent low recruitment that suppresses infected populations.