The Whatcom County Health Department in Bellingham, Washington has issued their final report into the E. coli O157:H7 outbreak that sickened at least 25 children. The outbreak appears to be over.
All of the ill people either attended the Milk Makers Fest between April 21 and 23, 2015 at the Northwest Fairgrounds in Lynden, Washington; helped with the event between April 20 and April 24, or were in close contact with people associated with the event. Environmental contamination with E. coli O157:H7 at the Dairy Barn at the fairgrounds was the likely source of this outbreak.
Case counts were calculated based only on lab-confirmed infections with E. coli O157:H7 or physician-diagnosed hemolytic uremic syndrome (HUS), which is a complication of an E. coli infection. Twenty-five peoeple were confirmed cases. Nine of those cases were considered secondary (the ill person didn’t attend the event but had close contact with someone who did). No one died. Ten people were hospitalized. And six people developed HUS.
Multiple samples were taken from the environment where the event was held. They were collected on April 30 and May 13, 2015 and tested in a lab. Several areas of the north end of the Dairy Barn at the fairgrounds were contaminated with the same strain of E. coli that made people sick. Negative results “do not rule out contamination in other parts of the barn.”
The outbreak strain of E. coli O157:H7 was identified in the manure bunker, the hay maze area, bleachers by the east wall, and bleachers by the west wall in the Dairy Barn. The report states that contamination most likely occurred before the Milk Makers Fest.
Any environment where animals have been kept, such as barns, should be considered contaminated with pathogenic bacteria. E. coli O157 can survive in the environment up to 42 weeks.
Interviews of patients, and those who did not get sick, revealed some results. Event attendees who reported washing or sanitizing their hands before eating lunch were less likely to get sick. Children who reported always biting their nails were more likely to become ill. Leaving animal areas without washing hands may have contributed to an increased risk of transmission. And eating in animal areas might have contributed to an increased risk.
The report ends with several recommendations, both for event organizers and the public. Organizers should have pans for cleaning and disinfection before, during, and after events, and ensure access to hand washing facilities with soap, running water, and disposable towels.
The public should always consider any environment where animals are kept, whether a barn, farm, or petting zoo, to be contaminated with bacteria. Hands should always be washed right away when leaving animal areas, after removing dirty clothing or shoes, and before eating. Adults should supervise young children. Be aware that shoes, clothing, and stroller wheels can become contaminated and be a source of illness after leaving an animal area.
Finally, the nine secondary cases highlight the need to be careful when caring for those who are ill with diarrheal illnesses. Always wash your hands throughly with soap and water after using the bathroom or changing a diaper. Always wash hands before and after preparing food for yourself and others, and before eating. Stay home from work or school if you have diarrhea. And check with your doctor if diarrhea lasts longer than three days or is watery and/or bloody. Many schools and day care centers have special rules for those who have been diagnosed with E. coli infections.