Giardia lamblia

Giardia lamblia is an infection of the small intestine. It is contracted when a person puts something in their mouth that has been in contact with Giardia lamblia. This most frequently includes contaminated water, (swimming pools, hot tubs, lakes or rivers) though a person can also be infected by putting their mouth on toys or raw foods.

Different individuals with the same strain of Giardia lamblia render a variety of symptoms throughout the course of the disease.  Such symptoms frequently include: diarrhea, loose or watery stool, stomach cramps, and lactose intolerance. Rare infections include disaccharide intolerance. These symptoms begin one to two weeks after infection and may lead to weight loss and dehydration.  Effects of Giardia lamblia persist for two to six weeks, though some people experience no symptoms upon infection.

Many adults have a lasting immunity to the infection, but children remain quite susceptible. The overall incidence of infection in the United States is approximately two percent of the population.

More Information on Giardia lamblia:

• Foodborne Pathogenic Microorganisms and Natural Toxins 1992 (Bad Bug Book) - FDA

• Giardiasis - Centers for Disease Control and Prevention (CDC)

Food Safety Project Director
Catherine H. Strohbehn, PhD, RD, CFSP
HRIM Extension Specialist
Adjunct Associate Professor
Hotel, Restaurant, and Institution Management
Iowa State University

Consumer and Processing Food Safety and Science
Sam Beattie, PhD
Food Safety Extension Specialist
Department of Food Science and Human Nutrition
Iowa State University Extension

• Article History
• Revision Date: 8/18/2009