Foodborne/Waterborne Illnesses

Problems/Case Studies

"Where's the Beef? Investigating Food-Borne Illness". Mr. David A. Wollert, Northeast State Technical Community College
This exercise deals with E. coli contamination of food products and the potential costs and benefits of food irradiation.
Although originally developed for an introductory microbiology course, it is also suitable for use in general biology courses, particularly during discussions of DNA and the causes and effects of mutations.

Supporting Materials: Format of Delivery, Student Learning Objectives, Student Resources.

CNN Video Clips Topic: Mad Cow Updates: Biology 5th Ed. CNN Ed 2001 (2:13)
Cattle afflicted with bovine spongiform encephalopathy (BSE) are shown staggering about.  In Britain, Ireland, and France, about 90 people have died after exposure to infected beef.  Neither BSE nor the human form of the disease (Creutzfeldt-Jakob disease) is believed to be a serious threat in the United States.  However, the human disease has an incubation period of ten to fifteen years.  Theoretically, an American could be infected in Europe and bring the disease into the country, but human-to-human transmission is extremely difficult.  The worksheet includes the URL for the U.S. Food and Drug Administration, which provides information about the disease and what is being done to keep it out of the United States. (Student worksheet provided on CD)

Topic: Goodbye Guinea Worm: Biology 5th Ed. CNN Ed 2001 (2:59)
Citizens of Ghana are shown suffering from guinea worm infection.  They became infected when they drank water containing the larval form of the worm.  Over the course of a year, the larvae develop into adults that can reach up to three feet in length.  Emergence of adult worms through the skin causes pain, scarring, and secondary infections.  Ex-President Jimmy Carter is working to eradicate the Guinea worm by teaching people to treat potentially infective water with chemicals and filtration and to monitor and treat known infections.  These efforts have succeeded in decreasing the number of infections in Ghana by ninety-five percent. (Student worksheet provided on CD)


"Detecting Mad Cow Disease".  Prusiner, Stanley.  Current Issues in Biology Vol. 2.  July 2004.  pp.2-11.
Mad Cow Disease debuted in America in December 2003.  The bovine spongiform encephalopathy (BSE) posed a particularly difficult problem for scientists as prions, which incubate without symptoms for years, could lead to epidemics.  Prions cause multiple diseases in an array of animals such as deer, elk, and sheep.  The prion is actually a form of protein PrP that can twist into an abnormal, disease-causing shape.  These prions are especially difficult to kill due to their ability to resist heat, radiation, and chemicals that can kill other pathogens.  Unlike the somewhat inefficient way the US detects Mad Cow disease now through immunohistochemistry, antibodies are being developed to detect all prions, especially the diseased proteins.  Prions can arise spontaneously which is why a feed ban must be implemented to prevent cows from eating the remains of other slaughtered cows.  Prions are being transferred via feed; prions can also transpire spontaneously.