It is estimated that 180 million kittens are born in the U.S. each year, many of which are abandoned, orphaned, or relinquished for fostering by thousands of U.S. animal shelters. Roughly 15% of kittens fostered by these shelters will die or be euthanized because of illness before the age of 8-‐weeks. Most of these kittens have diarrhea or post-‐mortem evidence of gastrointestinal disease at the time of death. The long-‐term goal of this research is to identify infectious causes and life-‐saving prevention or treatment strategies to reduce the death toll of gastrointestinal illness in foster-‐age kittens. In published preliminary data, the researchers have shown that enteropathogenic E. coli (EPEC) is commonly cultured from the feces of foster-‐age kittens and that attachment of EPEC to the intestinal epithelium is significantly associated with mortality. They have additionally shown in healthy kittens that a member of the normal bacterial flora, E. hirae, also attaches to the intestinal epithelium and is often absent in the intestines of sick kittens. In these studies, they will determine if a simple PCR test, performed on kitten feces, can be used to diagnose EPEC infection and whether there are specific genetic or behavioral attributes of EPEC that are associated with kitten mortality. Other goals will be to identify antibiotics useful for treatment of EPEC infection in kittens, and to generate preliminary data in support of using E. hirae or other commercially available probiotics to help treat kittens with diarrhea due to EPEC infection.