Which of the following is NOT an example of a Category B substance?

The designation of Category B substances pertains to infectious substances that are considered to pose a lesser risk compared to those classified as Category A. Category B substances are typically capable of causing disease in humans or animals, but they are not expected to result in a life-threatening condition or a public health emergency when exposed in a manner consistent with their normal handling procedures.

Ebola virus, classified as Category A, is known for its high mortality rate and potential to be a significant public health risk. This contrasts with the other substances, such as HIV, Hepatitis B, and West Nile Virus (WNV), which, while still serious, do not carry the same level of threat in terms of potential for widespread transmission and severity of outbreak. Thus, categorizing the Ebola virus as a Category A substance helps to underscore the urgency and heightened precautions that are necessary when handling it, in contrast to the lesser but still notable risks associated with the other infections listed.