Today, the Portland Water Bureau received results from two additional samples that were positive for Cryptosporidium, a potentially pathogenic microorganism. These detections from samples collected Tuesday, Feb. 7 and Wednesday, Feb. 8, from the Bull Run Watershed, are the fifth and sixth positive samples this year. The levels detected were low, with one Cryptosporidium oocyst detected in one sample and two Cryptosporidium oocysts in the second.
The Portland Water Bureau continues to closely coordinate with public health officials. At this time, there is no evidence of an increased public health risk as a result of these most recent detections. We continue to recommend that people with severely weakened immune systems seek specific advice about drinking water from their health care provider. However, there is still no need for the general public to take additional precautions.
“All identified cases of cryptosporidiosis, the disease caused by Cryptosporidium, are reported to state and county health officials” said Dr. Jennifer Vines, Deputy Health Officer, Multnomah County. “So far, the county’s ongoing disease surveillance has shown no unexplained increase in Cryptosporidium cases.”
Symptoms of cryptosporidiosis may include diarrhea, nausea, vomiting, stomach cramps, and fever. The symptoms can range from mild to severe. Cryptosporidiosis is not the only illness or condition that can cause these symptoms. These symptoms are common in the general population this time of year – up to 2 percent of the public can have similar symptoms on any given day (11,000 people in Portland). Health professionals recommend that you seek medical advice if you are experiencing these symptoms and they persist for more than a few days.
The Portland Water Bureau currently does not treat for the parasite Cryptosporidium because of a variance issued by the State of Oregon Health Authority (OHA) in 2012.
As required by the conditions of the variance, the Portland Water Bureau had been testing for Cryptosporidium at the source water intake twice a week. Since Jan. 8, after the initial detections, the Portland Water Bureau began monitoring at the source water intake at least four times per week. This will continue for one year to demonstrate whether the Cryptosporidium concentration in the source water is less than 0.075 oocysts per 1,000 liters.
“The Portland Water Bureau is continuing to work with our partners at Multnomah County Health Department and Oregon Health Authority to ensure that public health is protected,” said Water Bureau Administrator Mike Stuhr. “We will continue to closely monitor our drinking water source and communicate any findings with the public.”
The Water Bureau is continuing its investigation into the recent detections. While no specific source has been identified, scat from wildlife found in the Bull Run are the most likely source of the Cryptosporidium detections which may have been washed into the reservoirs during the recent winter storms. The Water Bureau will continue to notify the public if any additional precautions are necessary. In the meantime, the Water Bureau is evaluating potential operational changes such as temporarily activating our secondary groundwater source.
Additional information regarding Water Bureau’s treatment variance and answers to frequently asked questions are available at www.portlandoregon.gov/water/lt2treatmentvariance. Customers with questions regarding water quality can call the Water Line at (503) 823-7525.