Don’t Drink the Water

The caution “Don’t drink the water” may have more application to us than we realize. Recently, health officials have recognized a disease known as giardiasis in individuals who drink inadequately treated water. The disease occurs in all climates from the arctic to the tropics. Indeed, Giardia lamblia (commonly known as giardia) has become the most frequently isolated intestinal disease-causing parasite in the United States and in some of the developing countries of the world, where as many as 97 percent of children are infected with this organism.

Although giardia was not associated with human disease until recently, the organism was given its present name in 1915 and has been widely accepted as a cause of human diarrhea since that time. Once infected, most individuals may expect to develop the disease within about nine days. Symptoms include a bloated feeling, cramps, and diarrhea. Although some children fail to show symptoms of the disease after infection, 81 percent of adults do. Little or no immunity is established during the process of infection, and individuals may remain contagious for up to fourteen months after symptoms cease.

All water that does not come from an approved water source must be treated in order to assure freedom from giardia. Therefore, giardiasis has a seasonal peak occurring in the summer and early fall months when people are involved in outdoor recreational activities and tend to drink untreated water from rivers or lakes.

The following procedures may be followed to reduce the risk of infection:

Boil untreated drinking water or heat it to at least 70 degrees C (158 degrees Fahrenheit) for ten minutes.
Add iodine tablets to drinking water and allow it to sit for at least eight hours before use.
Use a water filtering system. (Note: Some but not all filtering systems are effective in removing giardia from water sources.)
Infants should be breast-fed when possible to reduce transmission of this organism in areas of the world where infection is difficult to avoid.

Though untreated water is the major transmitter of the organism, giardia can also be transmitted in other ways, such as through hand-mouth contact. As a result, a large number of cases appear in children attending day-care centers. In several studies, it has been shown that as many as 37 percent of children attending day-care centers are infected with this organism. When these children return home, they often infect their families.

To reduce the risk of infection from this type of transmission, it is important to do the following:

When caring for an infected child, wash your hands frequently and carefully. This can reduce the transmission of the organism by as much as 50 percent.
Use caution when diapering an infected child, and properly dispose of soiled diapers to further reduce the likelihood of transmission.

Diagnosis of giardiasis is relatively straightforward but not always easy. You should see your physician for treatment if you experience symptoms.—Donald N. Wright, professor of microbiology, Brigham Young University