That's Right !!

5. Which of the following are single-celled microbes called protozoa?

1. Giardia
2. Norwalk
3. Cholera
4. a & b
5. All of the above

A - Giardia lamblia is a protozoa that lives in water and can cause diarrhea and cramps. Norwalk, a virus, can also be found in water and causes vomiting, diarrhea, and abdominal pain. Cholera (described in the first question) is a bacterium. Virus, bacteria, and other microbes that can cause illness are called pathogens.

The US EPA requires that water be disinfected at a level that eliminates 99.9% of waterborne pathogens.

U.S. Food & Drug Administration, Center for Food Safety & Applied Nutrition, Foodborne Pathogenic Microorganisms and Natural Toxins Handbook. http://vm.cfsan.fda.gov/~mow/chap34.html

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