Affected herd. A herd of livestock in which there is strong and substantial evidence that Mycobacterium bovis exists. This evidence should include, but is not limited to, any of the following: Histopathology, polymerase chain reaction (PCR) assay, bacterial isolation or detection, testing data, or epidemiologic evidence such as contact with known sources of infection.
9 CFR § 77.2
As used in this part, the following terms shall have the meanings set forth in this section except as otherwise specified.