Swimming at various waterfall ponds and streams throughout the island is dangerous due to a bacteria called Leptospirosis.

According to the Department of Health’s Web site, Leptospirosis is a disease that affects humans and animals. It is usually caused by exposure to water contaminated with the urine of infected animals. Routes of entrance for the bacteria are broken skin, and the mucous membranes of the eyes, nose, and mouth.

Animals known to carry it are cattle, pigs, horses, and rats. Leptospirosis is not known to spread from person to person.

The typical symptoms of Leptospirosis are fever, headache, chills, muscle aches, vomiting, jaundice (yellow eyes and skin), red eyes, abdominal pain, diarrhea, and/or a rash. The disease is treated with antibiotics such as penicillin or doxycycline. Left untreated, it can cause kidney damage, meningitis, liver failure, and respiratory distress. In rare cases, death occurs.

So far this year, there have only been three cases in Hawai‘i, according to Dr. James Marzolf, a physician and chief of Epidemiology with the state Department of Health Some people swim in the ponds frequently and never get sick; they claim that Leptospirosis is an “individual thing.” Dr. Marzolf said people should not trust this belief.

“Some people could swim in the ponds and never catch it (Leptospirosis), just like some could walk to the store and catch a cold, while others may not. That does not mean they have an immunity. A number of factors are involved.”

Even if you have no broken skin and keep your head above water, Dr. Marzolf says you still risk contracting the disease.

However, Dr. Landis Lum, a family practice physician with Kaiser Permanente and a clinical associate professor of family and community medicine at the University of Hawai‘i’s John A. Burns School of Medicine, differs. In an article in the Honolulu Advertiser’s Prescription Column (June 11, 2000), he wrote that most people who swim don’t contract Leptospirosis. Dr. Lum could not be reached for comment.

Dr. Lum also wrote in his article that swimmers can reduce their chances of contracting Leptospirosis by not swimming in rivers and ponds if they have open cuts or abrasions, and by not swimming underwater.

“Will I go swimming again? Yes, if I have no cuts or abrasions. But this time, I won’t dive under the water,” said Dr. Lum.

When experts disagree, swim at your own risk.