Giardiasis and Giardia Intestinalis Definition

An illness resulting from infection with the protozoan Giardia lamblia (also called Giardia intestinalis). Giardia are abundant in fresh water throughout the United States; infection occurs through drinking contaminated water.

The protozoa infect the small intestine of humans and animals and can survive for extended periods without a host. The most common means of infection is through swallowing water in recreational settings, such as lakes, rivers, and streams.

Fountains, swimming pools, and hot tubs that lack proper chlorination also may harbor Giardia. Giardiasis also spreads through fecal contamination by direct contact, such as by changing diapers, and can occur as a foodborne illness spread through poor food safety practices.

Symptoms of Giardiasis and Treatment

Symptoms develop after an incubation period of 7 to 10 days and include diarrhea, excessive flatulence (gas), abdominal discomfort, and nausea. The diarrhea is watery and has a greasy appearance. Some people also experience fatigue, loss of appetite, and rapid weight loss.

It is also possible to have giardiasis and have no symptoms. Stool samples examined under the microscope typically contain both cysts and trophozoites, the immature and mature forms, respectively, of the Giardia.

Treatment is antibiotic medications and antifungal medications. The course of illness runs four to six weeks with treatment, after which most people recover without complications or residual consequences. Without treatment giardiasis may persist for six to eight weeks, with gradual though complete recovery.

Medications to Treat Giardiasis

MEDICATIONS TO TREAT GIARDIASIS
albendazolefurazolidone
metronidazolenitazoxanide
paromomycintinidazole

See also AMEBIASISBABESIOSIS; DRINKING WATER STANDARDS.

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