WATERLOO - He understood the risks.

In the days following the flood last month, Tom Arthur spent several days on Sans Souci Island helping clean mud and debris out of friends' home and garage. With city water cut off to the neighborhood, Arthur had to find a new way to power up equipment.

"I put a sump pump in a back area that had some settled floodwater and pumped that into my high pressure washer. I drenched myself in that water for days while I was cleaning off their stuff," he said.

Three days later, he began to pay the price for his generosity. A small, pimple-like breakout covered his lower legs. On closer examination, Arthur said he could see where each individual parasite had burrowed into his leg.

Then the itching set in.

"It came with a vengeance," Arthur said. "It really was debilitating."

He waited through the weekend, coating his legs in lidocaine to relieve the itching, before seeing his family doctor. Dr. Michael Deters recognized the source of Arthur's discomfort and prescribed an antibiotic and anti-inflammatory medicine.

Dr. Todd Lawrence, associate medical director for the emergency department at Covenant Medical Center, said he hasn't encountered any flood-related parasites. But he has seen an increase in skin infections since the water receded. The infections, which usually result in an abscess that must be drained, can be treated easily with antibiotics.

Though there is no way to prove the infections are caused by the flood, Lawrence said most of the new patients encountered dirty water.

Lawrence said those who have an infection, which would look like a large pimple, should see a doctor if it is red and swollen or appears to be spreading.

"We suggest no popping it. Squeezing things out only pushes the infection deeper and it gets worse. Instead, they need to come in and have it drained," Lawrence said.

While the skin infection cases are tapering off, Lawrence said he is still seeing an increase in the number of patients suffering from respiratory problems.

"For the most part, these people have no history of asthma or emphysema but they have had long exposures to the chemicals used to clean these homes. It's called chemical bronchitis, and really the only way to avoid it is to wear a mask and have good ventilation," Lawrence said.

The Black Hawk County Health Department also is investigating a gastrointestinal illness reported by several people working or living at the American Red Cross shelter in the University of Northern Iowa's West Gym. Department Director Tom O'Rourke said the characteristics of the illness do not suggest a food-borne cause, but final lab work has not been completed.

O'Rourke said nearly a dozen people reported the illness to doctors in the last two weeks. Though some have called the illness the norovirus, O'Rourke said he won't be able to identify the cause until lab work is complete.

Symptoms of the norovirus include nausea, vomiting, diarrhea and low-grade fever. It is highly contagious and difficult to contain and manage.

"These kinds of things often happen in residential facilities or schools, but they also happen in the middle of the desert where they never see any floods," O'Rourke said. "We have no reason to believe this is flood-related, except these people are all living together because of it."

Contact Emily Christensen at (319) 291-1570 or emily.christensen@wcfcourier.com.