BAKER CITY — Samples of city water taken Wednesday contained cryptosporidium, Baker City Manager Mike Kee said Sunday, but the lab results don’t tell authorities how, when and where enough of the parasitic protozoa entered the city water supply to sicken dozens of people.
Widespread diarrhea, stomach cramps and other symptoms have afflicted people over the past 10 days in this Eastern Oregon city.
Results from a Seattle lab showed small numbers of crypto “oocysts” in six of seven water samples. But the numbers of oocysts per sample — ranging from one to three — would not account for the extent of illness in the community, according to Dr. Bill Keene, senior state epidemiologist.
Kee said Keene told him it’s likely that a much larger number of oocysts — perhaps in the tens of thousands or more — entered the water supply and then spread unequally in the system.
This unequal distribution, combined with people being variably susceptible to crypto’s effects, explains why, in some families, only one member has been sick even though all members drank city water.
City workers took additional water samples Saturday from Good-rich Lake, the main city reservoir, along with samples of mountain goat feces, Kee said. Keene will test the goat scat for crypto.
The parasite gets into water through feces, whether animal or human, and both city and state officials say the large mountain goat population near Goodrich is a plausible source of the crypto.
City workers also took water samples Monday from all other city water sources — a dozen streams and springs in the Elkhorn Mountains and a well that contains water pumped in from the watershed last winter and this spring.
Kee said the city hopes to rescind the order for residents to boil water used for drinking, brushing teeth, washing dishes or cooking, as soon as possible. “But we really need to find out what made this happen,” Kee said. “We certainly don’t want to go off the boil order and then have another round of people getting sick.”
Results received Saturday from five of seven water samples also showed giardia cysts. However, Kee said there’s good reason to believe that giardia, another waterborne parasite, is not the source of the problems in Baker City.
First, the lab did not test the giardia cysts to find out if they are “viable” — that is, capable of causing illness. The likelihood is that the cysts are not viable, Kee said, because giardia, unlike crypto, is vulnerable to the chlorine the city adds to its drinking water as a disinfectant. Giardia lacks the protective oocyst that protects crypto from chlorine.
Kee said health officials told him they expected lab tests to show giardia cysts, but the chlorine concentration is sufficient to make those cysts not viable.
Second, Kee said, 10 of the 13 people confirmed to be infected with crypto were also tested for giardia. None of the 10 were infected with giardia, he said. Kee said at least three people who reported symptoms consistent with crypto have been tested and the tests were negative for both crypto and giardia.
Symptoms of giardia infection are similar to those for crypto, although giardia tends to cause more severe diarrhea, as well as vomiting, gas and bloating.
Kee said both the city and county have sent emergency declaration requests to the state. That would allow the city and county to ask for extra resources if needed and also give the agencies more flexibility in spending money — if special equipment were needed, for instance. Kee said officials at St. Alphonsus Medical Center-Baker City told him that the number of people visiting the emergency room with crypto-like symptoms dropped substantially on Saturday.
He said Keene and other state experts are trying to figure out not only when the infectious level of crypto entered the city’s water, but how.
Kee said he has talked with several people who don’t live in Baker City, but who were visiting in early or mid-July, who came down with persistent diarrhea and stomach cramps after they returned home. Those likely cases add to the probability that the city water supply is the source of the outbreak.
Cryptosporidium spp. “Crypto”
Where crypto occurs
Crypto may be found in anything that has come into contact with contaminated feces, including soil, food, water or surfaces.
How crypto can be contracted
• Accidentally putting something in your mouth or swallowing something that has come in contact with infected stool.
• Swallowing recreational water that has come into contact with feces.
• Eating uncooked food that has been contaminated. Wash all fruits and vegetables with uncontaminated water if intending to eat them raw.
• Touching mouth with contaminated hands. Hands can become contaminated by touching surfaces, changing diapers, caring for an infected person or handling an infected animal.
Who is at high risk for contamination?
• Children who attend day care
• Child care workers
• Parents of infected children
• People who care for infected people
• International travelers
• Backpackers, hikers and campers who drink untreated water
• People who drink from untreated shallow, unprotected wells
• Swimmers who swallow water from contaminated sources
• People who handle infected animals
• People exposed to feces through sexual contact