2000 E. coli Outbreak at a Dairy Farm
Crump et al (2002) discussed an outbreak of E. coli O157:H7 among visitors to a dairy farm in Pennsylvania in September, 2000. A case control study among the visitors was conducted to identify the risk factors of infection, along with a household survey to determine the rates of diarrheal illness. The total number of confirmed or suspected E. coli O157:H7 cases was 51. The median age among the patients was four. Eight of the cases developed hemolytic uremic syndrome (HUS). The environmental investigation indicated that 28 (13%) of 216 cattle on the farm were carrying E. coli O157:H7. The isolates from the animal had an identical DNA fingerprint pattern (by pulsed field gel electrophoresis) compared to the isolates from the patients. The bacteria were recovered from various surfaces in public access areas of the farm.
The investigation concluded that this large outbreak of E. coli O157:H7 was most likely a result of contamination of both animal hides and the environment. Hand washing was protective in preventing against transmission of the pathogen.