Health authorities said Thursday they still were seeking the source of a parasitic outbreak in Lawrence as the number of cases continues to rise.

Officials also said they thought the city’s water supply was safe from cryptosporidium — but admitted they had not yet tested to ensure its absence from Lawrence drinking water.

“We’ll probably start testing soon,” said Shari Stamer, the city’s water quality manager.

The number of cryptosporidium cases in Lawrence has increased to 15, up from 11 when the outbreak was disclosed a week ago today, said Kay Kent, director of the Lawrence-Douglas County Health Department. There were no cases reported in Douglas County in 2002.

Federal and state health officials are in Lawrence helping investigate the outbreak.

Students at four Lawrence elementary schools Thursday were sent home with questionnaires designed to help authorities determine how far the disease has spread — and if the outbreak has a common source.

“We’ve had some anecdotal information that there may be more diarrhea in the community, so we’re really thinking there might be more cases out there,” Kent said.

She added: “The truth of the matter is we do not know the source.”

Young victims

The Lawrence-Douglas County Health Department has requested assistance from the Centers for Disease Control and Prevention and the Kansas Department of Health and Environment in conducting an investigation into cryptosporidium outbreak in Douglas County. Thursday at the Lawrence-Douglas County Health Department CDC and KDHE staff work with local public health staff on the investigation. Kim Ens, Lawrence-Douglas County Health Department disease control program coordinator, left, Cheryl Baniz Ocfemia, epidemiologist with KDHE, review data from Douglas County.

Cryptosporidium is a microscopic parasite that causes diarrhea, loose or watery stool, stomach cramps, upset stomach and a slight fever. It can be fatal to patients with weakened immune systems, such as the young, elderly or people with HIV. More than two-thirds of those who contract cryptosporidiosis are children — and Kent said Thursday that 11 of the 15 Lawrence victims were younger than 18.

The parasite is easily passed in swimming pools, because it is able to survive outside the body for long periods of time and is resistant to levels of chlorine typically found in pools.

In Lawrence, the outbreak was serious enough for officials to temporarily shut four swimming pools for decontamination. They were closed from Friday until Sunday, some of the hottest days of the summer.

Kent said Thursday officials had known since late July that at least one person with cryptosporidium had been swimming, but they chose not to take action at the pools until the number of cases grew larger. The closure orders came after consultation with the federal Centers for Disease Control and Prevention and the Kansas Department of Health and Environment.

She said there was not a standard number of cases that prompts pool closures.

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“One is not it,” she said. “But it really had to do with the fact of the number (of cases), the number that had … some similar type of contact.”

Terrorism unlikely

While the source is unknown, Kent said some suspects were low on the list of possible causes. Terrorism, for example, is unlikely.

“We’ve asked that question ourselves,” she said. “Just because of the location of the cases and where they occurred, we don’t believe so. But we asked that question — you always ask that question these days.”

Kent said the city’s water supply was not suspected.

“At this point in time, we have no reason to believe that the general water supply is implicated,” she said. “We are looking at all risk factors, though.”

Stamer said the city was not required to test the water supply for cryptosporidium, but federal officials were expected to order monthly testing by next year. An effective test only recently became available.

Other tests of the system are designed to detect drinking water contamination, Stamer said.

“Filtration is the barrier for cryptosporidium — chlorine does not kill it,” she said. “We watch our filter performance, we’ve done filter performance testing and that type of thing.”

Lawrence draws its water from Clinton Lake and the notoriously dirty Kansas River. Stamer said cryptosporidium might be lurking in those waters before arriving at the city’s treatment plants.

“I can’t tell the public it’s not out there, at least in the source water,” she said. “It’s not a sterile environment, we know that.

“Because of how we handle our business here, at the plants, and how the work is being done, I’m pretty confident the water is safe.”

City pools aren’t regularly tested for the parasite in Lawrence or elsewhere, said Jimmy Gibbs, the city’s aquatics supervisor. Such tests would cost upwards of $1,000 per sample, he said.

“Right now, there are no basic regulations or standards,” Gibbs said. “It’s kind of one of those things that when it does show up, then you react to it.”

Investigation

Kent said city pools on Thursday were tested for the parasite for the first time. It was not known late Thursday when those test results would be available.

Four officials from the CDC and one from KDHE have been in Lawrence this week helping to investigate the source of the outbreak.

“They are taking it very seriously,” Kent said.

Questionnaires went to students of four randomly selected schools — Hillcrest, Prairie Park, Quail Run and Sunflower. The cases do not appear to be centered in any particular neighborhood, Kent said.

“We actually are going to be pinpointing them,” she said. “Just getting addresses at this point, they appear to be scattered throughout” the city.

She said families should return the surveys today, so officials could analyze the results this weekend. Officials also will conduct phone interviews with residents in coming weeks.

“We will be interviewing the cases, then, to find out what they’ve been doing, to find out what the risk factor is,” Kent said.

She did not have a target date for completing the investigation.

“It’s unusual,” Kent said of the outbreak. “So it’s very important to find the source and look at ways to intervene or prevent it.”