A 14-year-old girl comes to your office with symptoms of diarrhea, flatulence, greasy stools, stomach cramps, and nausea. In the past 2 weeks, the patient has lost 10 pounds. During the patient interview, you find out from her mother that the family went camping about 3 weeks earlier. You also discover that the patient drank from a stream while on a hike. The patient shares with you that she saw beavers in the stream during the hike. No other family members are exhibiting any symptoms. After several laboratory tests, the patient is diagnosed with giardiasis, a parasitic infection often carried by beavers. The incubation period for Giardia is 1 to 2 weeks; however, adults do not always show signs of the infection. Risk factors for infection with Giardia include children in child care settings, people in close contact with infected persons, people who drink or swim in contaminated water, and people who have contact with infected animals. The patient is placed on antimicrobial therapy. As you read this chapter, consider the following questions:

1			What part of the cycle of infection caused the problem for the patient?
2			How could the patient have avoided this infection?
3			Why are the other family members not showing symptoms of the infection?
4			Should the patient's family members be tested for the infection?