Giardiasis (GEE-are-DYE-uh-sis), also known as Beaver Fever, is caused by a microscopic parasite, Giardia intestinalis, and can result in a diarrheal illness in humans. It is the most commonly reported pathogenic protozoan disease in the U.S. and is particularly prevalent among hikers and campers. After infecting a person or animal, the parasite lives in the intestine and is passed in feces. It has a protective outer shell and can survive in the environment for periods up to months or longer. During the past 20 years, Giardia infection has become a common cause of waterborne disease in humans in the United States. The parasite is found worldwide and within every region of the U.S.
Giardia is commonly found on surfaces or in soil, food, or water that has been contaminated with feces from infected hosts, which can include humans, domestic animals, and most wild animals. It can be be spread by
- Accidentally swallowing the parasite after picking it up from contaminated surfaces such as bathroom fixtures, changing tables, diaper pails, toys, or from people or animals that are ill with the disease, etc.
- Drinking contaminated water or using contaminated ice.
- Accidentally swallowing contaminated recreational water in swimming pools, water parks, hot tubs or spas, fountains, lakes, rivers, springs, pond, or streams.
- Eating uncook contaminated food.
Symptoms of Giardia normally begin 7 to 14 days following infection and can include diarrhea, flatulence, greasy stools that tend to float, stomach or abdominal cramps, and upset stomach or nausea. Symptoms may last 2 to 6 weeks and sometimes longer. The illness may lead to weight loss and dehydration. About half of those who become infected have no symptoms.
Prescription drugs such as tinidazole and nitazoxanide are available to treat Giardia infection. Cure rates with single-dose tinidazole range from 80% to 100%. Consult a physician for diagnosis and treatment.
In 2008, there were 18,908 cases of Giardiasis nationally that were reported to the CDC. As of August 15, 2009, there have been 9,727 cases reported nationally. States with the highest number of reported cases thus far in 2009 include New York 1,185 (of these 463 were reported in New York City); Florida 1,184; California 1,018; Georgia 595; Ohio 477; Pennsylvania 457; Michigan 347; and Massachusetts 318. (Note: The disease is not reportable in Indiana, Kentucky, Mississippi, and North Carolina.)
(Sources: CDC and Giardiasis.org)