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It's a very crypto Thanksgiving—and we don't mean currency.
On Wednesday, Portland Water Bureau announced that a Cryptosporidium oocyst was detected in a 50-liter sample of Bull Run Water on Nov. 19. This is the second oocyst detection since last Sunday, Nov. 11, but the Portland Water Bureau says that after consulting public health officials, it's found "customers do not need to take any additional precautions."
Cryptosporidium is a potentially disease-causing microorganism that can cause vomiting, diarrhea, fever and stomach pain if ingested. An oocyst, according to the Centers for Disease Control and Prevention, is a "hardy, thick-walled stage of the life cycle of coccidian parasites."
Jaymee Cuti, a spokesperson for the Portland Water Bureau, says the source of contamination is likely wildlife.
"Past Cryptosporidium outbreaks in the U.S. have typically been associated with significant amounts of Cryptosporidium contamination from sources such as human sewage or runoff from livestock," Cuti tells WW. "Strict restrictions are in place to protect the Bull Run water source and surrounding area from such contamination."
In other words: Bull Run is sealed off from people and farming, so a bear probably pooped in the reservoir. Bull Run is unique in that the 147-square-mile basin at the base of Mount Hood is protected year-round by locked gates and one live-in ranger.
In the past, wildlife defecation has triggered readings for both crypto and E.coli. But former Multnomah County health officer Dr. Gary Oxman told WW in 2012 that serious health hazards, at the time related to E. coli, could only be caused by many, many bears defecating continually, or "one bear that had just the right organism, defecating repeatedly."
According to Wednesday's release, the water bureau is still serving all of the reservoir's water. Bull Run is not currently treated for Cryptosporidium, as is required under drinking water regulations, but the city is working to "install filtration by 2027 under a compliance schedule with the Oregon Health Authority."
"In the meantime," the release reads, "the Portland Water Bureau is implementing interim measures such as watershed protection and additional monitoring to protect public health."
People with compromised immune systems who get water from Bull Run are advised by the Environmental Protection Agency to consult with their doctor about whether or not they should drink tap water.
The areas that receive water from Bull Run include: The Portland Water Bureau and Burlington, City of Gresham, City of Sandy, City of Tualatin, Green Valley, GNR, Hideaway Hills, Lake Grove, Lorna Portland Water, Lusted, Palatine Hill, Pleasant Home, Raleigh, Rockwood, Skyview Acres, Tualatin Valley, Two Rivers, Valley View and West Slope Water Districts.