The intestinal maladies of campylobacter and giardia are enjoying a resurgence in Idaho this year, state health officials say.

So far this year, 123 people have suffered infections of campylobacter or giardia, which cause diarrhea. They usually do not make people seriously ill, but the very old and very young may experience dehydration.The incidence of campylobacter infection is up 44 percent from this point last year. The incidence of giardia is up 33 percent.

"It's not outrageous," said Fritz Dixon, chief of the Bureau of Preventive Medicine. For unknown reasons, the two diseases run in cycles, high some years and low other years, he said.

Most people who come down with campylobacter infections suffer diarrhea and nausea for up to four days. In severe cases, antibiotics may be needed.

People commonly contract campylobacter infections from animal waste, unpasteurized milk or food left out of the refrigerator too long, said Helen Stroebel, nurse epidemiologist for the Southwest District Health Department.

The southwest district office in Caldwell has reported 11 cases of campylobacter infections this year, the second-highest number in the state. Twelve cases have been reported in south-central Idaho; other cases are spread throughout the state.

While campylobacter infections stem from bacteria, giardia is caused by parasites common in rivers and lakes across the West, Dixon said. The number of cases is higher in the summer because campers drink water which may be contaminated with a intestinal parasite that originates in animal feces.

Symptoms may last up to three months, but drugs are available to effectively treat the illness.

To avoid catching giardia, Dixon recommends boiling all water from Idaho streams, rivers and lakes. "Just a quick, rolling boil is enough," he said.