The investigation was limited by several factors. Not all party attendees were interviewed;
individuals who were less severely ill may not have been reported or sought medical care.
Also, separate interviews were not conducted for all reported secondary outbreak cases of
STEC as they were known contacts or family members of primary cases. Therefore, additional
cases may exist. The environmental investigation was limited by the difficulty in isolating STEC
O157 from bovine fecal samples and due to intermittent shedding of STEC in feces6
. The calf
was moved to pasture shortly after the house party and investigators were not able to obtain
additional environmental samples.