Lower Hanawi Falls ~ Photo by Ken Schmitt
Hike Healthy – Be Aware of Waterborne Illnesses
Hawai‘i is a hiker’s dream, with year-round good weather, beauty and easy access to trails. Many of these trails end at streams and waterfalls that look crystal-clear, smell fresh and clean and invite the hot hiker to have a drink or swim. It is tempting to conclude that there is little chance of water contamination because the mountain ridge is so close. However, several contagious diseases may be present in fresh water streams and pools. Drinking even the freshest-looking water is dangerous without treating it first, and one should use caution when swimming. Salmonellae, Salmonella typhi (typhoid fever), and e. coli can all be found in fresh water ponds and streams. There are several other waterborne illnesses found in Hawai‘i.
Some of the diseases are caused by parasites
Giardiasis is usually a mild intestinal illness, caused by the Giardia parasite and passed through feces of people or animals to the mouth of another person, either directly via hands or indirectly through drinking water or food. Symptoms begin seven to ten days after exposure, and include frequent, loose, pale, stools, with gas, cramps, fatigue and weight loss. Symptoms can last up to three weeks, though there may be no symptoms at all and individuals may recover on their own.
Cryptosporidiosis is a diarrheal illness, caused by a parasite that lives in the intestines of poultry, cattle, rodents, pets and humans. It can be transmitted person to person, animal to person or via contaminated food or water. Symptoms of watery diarrhea and cramping usually start about seven days after exposure and last up to a week. Immunocompromised persons may become seriously ill and even die from this disease. The illness is relatively uncommon in Hawai’i.
Another set of illnesses is caused by bacteria or bacteria-like organisms
Camplylobacteriosis symptoms include mild to severe diarrhea, stomach pain, fever, nausea and vomiting, with symptoms starting two to five days after infection. Along with drinking impure water, this bacterium can be acquired by eating improperly cooked chicken and raw milk, and from infected pets and other ill people.
Leptospirosis exposure can occur by swimming or walking in fresh water streams or puddles, or by coming into contact with wet soil or plants contaminated with infected animal urine, blood or tissues. The spirochete (a type of bacteria) enters broken skin or soft tissues; swallowing water is not necessary to catch this disease. Symptoms usually begin within one to two weeks, and can include fever, headache, chills and sweating, muscle pain, red eyes and vomiting. If the person is untreated, kidney, liver, blood and nervous tissue damage may occur. To avoid this potentially serious illness, hikers shouldn’t go barefoot in muddy areas, and should avoid swimming or wading, especially with open cuts or sores. Putting the head underwater is also risky because it exposes the mouth, nose and eyes to the spirochetes.
Shigellosis is caused by several kinds of Shigella bacteria, which can be spread from person to person through stools or soiled fingers of one person to the mouth of another person, by contaminated water or food, or by flies bred in infected feces. Symptoms begin within a day or two after exposure. Diarrhea, sometimes bloody, fever and stomach cramps usually resolve in about a week, however, some people may have no symptoms but still be infectious. A very small percent of those infected may develop chronic conditions, including arthritis.
Yersiniosis symptoms are fever, watery diarrhea and stomach pain that can feel like appendicitis. Young children are more likely to be infected than adults. Symptoms start from three to seven days after infection and may last up to three weeks, with a possible infectious period lasting for weeks or months after that. This bacterium is found in untreated water, raw milk, ice cream, tofu and shellfish. Yersiniosis is rare in Hawai‘i.
Hiking is good exercise, an escape from the busy routine, and a way to appreciate the beauty of nature. Simple precautions can keep one "hiking healthy." Carry plenty of drinking water from home, wear long pants and a long-sleeved shirt if brushing through wet areas, and don’t expose your cuts, sores or face to stream or pond water. If you do become ill and suspect it may be a waterborne disease, see your medical provider. Antibiotics or other treatments may reduce the severity or length of illness.
The information above is quoted or adapted from the Hawai‘i Department of Health Web site on Communicable Diseases, and from the Centers for Disease Control and Prevention, National Center for Infectious Diseases Web site.