CAMP LESTER, Okinawa — With weather warming up and more people out exploring the untamed parts of Okinawa, there’s a microscopic critter they need to beware of.

Leptospirosis can be found in fresh water that has been contaminated by the urine of infected animals, such as rodents, according to Lt. Troy Henderson, the environmental health officer at U.S. Naval Hospital Okinawa. People may also be infected through food or soil that has been contaminated.

Henderson said the bacterium can enter the body through broken skin, the eyes, nose or throat.

Domestic as well as wild animals can carry the bacteria, according to the U.S. Centers for Disease Control and Prevention’s Web site. Infected animals may or may not show symptoms of the disease, according to the CDC.

Leptospirosis also is listed as a potential health hazard in South Korea, according to the CDC’s Web site.

The bacteria is more common in the northern areas of Okinawa due to the large rodent populations in the agricultural area, Henderson said. It is especially prevalent from June through September, when the rodent population is highest, though doctors see occasional cases year-round, he said.

The hospital treated a case last week, he said, and he personally saw five or six cases last summer.

Hikers should be more cautious when walking or wading through fresh water three to five days after heavy rains, because that’s when water drainage is more likely to carry infected urine to streams and other fresh water, he explained.

Different strains of the bacterium are more virulent than others, Henderson said. The disease is treated with antibiotics.

Symptoms occur two to four days after contact and include sudden onset of headache and fever, he said. The infection can occur in two phases, according to the CDC, with the second phase called Weil’s disease, which can lead to meningitis, kidney or liver failure.

Initial symptoms can be confused with the flu, Henderson said, but people should let their doctor know if they were in contact with possibly contaminated fresh water two to four days before.

What to watch for:

Symptoms of Leptospirosis include:

High feverSevere headacheChillsMuscle achesVomitingJaundice (yellow skin and eyes)Red eyesAbdominal painDiarrheaIf the disease is not treated, the patient could develop kidney damage, meningitis, liver failure and respiratory distress. In rare cases death occurs.

Many of these symptoms can be mistaken for other diseases. Leptospirosis is confirmed by laboratory testing of a blood or urine sample.

— U.S. Centers for Disease Control and Prevention

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