What is giardiasis?

Giardiasis, also known as the giardia infection, is an infection of the intestines. It is caused very small parasite called giardia. The giardia parasite can be found all over the world and is a waterborne infection. The parasite that causes giardiasis is most commonly found in places where unsanitary water and poor sanitation. It may be found in places like lakes, swimming pools, and wells. The most common signs and symptoms include abdominal cramps, bloating, nausea and watery diarrhea. The giardia infection usually goes away within a couple of weeks. It is estimated that about two percent of people in the United States are infected with giardia.


While the infection is known as a waterborne infection, meaning it is transmitted via water sources, the infection can also be transmitted through food and person-to-person contact. The disease spreads through the feces of an infected person. The most common ways people become infected with the giardia infection is by drinking contaminated water, eating contaminated food, or swallowing water in water sources that have been infected with the parasite such as ponds, lakes, or streams. 

Who is at risk for the giardia infection? Hikers, backpackers who drink from potentially risky water sources such as lakes and streams, children in daycare centers, and people who have anal sex are more have the highest risk for the giardia infection. 

Not everyone who develops the giardia infection will develop symptoms. Some people who develop the infection may never develop signs or symptoms, however they will still be a carrier of the parasite and can spread it to others through their feces. When people do develop signs and symptoms, they usually show up in about one to two weeks after being exposed to the infection. The signs and symptoms of the giardia infection may include watery stools, fatigue, abdominal cramps and bloating, belching gas with a bad taste, nausea, and weight loss. The signs and symptoms of the giardia infection usually last two to four weeks. In some cases, they may last longer or even come back after a period of time. 

The best ways to prevent spreading the giardia infection includes washing your hands often, especially after using the bathroom, drinking only clean water, boiling or filtering water from streams and ponds when camping, avoiding brushing your teeth with contaminated water, avoiding eating raw foods grown in areas where giardia might be present, and abstaining fromoral and anal sex when you may be near a person or place in which the infection is present.