1.   The outbreak was eventually traced to a new strain of E. coli on hamburger meat.

2.   Both real and fictional outbreaks were traced to garbage from an oceangoing freighter that was fed to pigs.

3.   Britain has traced the outbreak to a farmer who fed his hogs restaurant scraps from infected meat that slipped into England.

4.   Health officials traced the outbreak to frozen strawberries served in federal food programs.

5.   The growers are also setting up a numbering system for every flat of berries to make sure inspectors can trace any outbreak back to a specific grower.

6.   The outbreak was traced to a batch of the drug tainted with the chemical NPTP, which is toxic to brain cells.

7.   The outbreaks were traced to imported cowpox vaccine contaminated with foot-and-mouth virus.

8.   The outbreak has been traced to a tainted fruit juice.

9.   There is a well-known story about the London doctor John Snow, who traced an outbreak of cholera to one pump spouting tainted water.