Which disease is NOT mentioned as a vaccination requirement for horses?

The vaccination requirements for horses can vary based on the specific regulations of different regions or organizations, but typically, certain core vaccines are universally recognized as essential for horse health. Among the options listed, influenza is often not considered a core vaccine that is mandatory for all situations or events, especially in comparison to the other choices.

Rabies, tetanus, and West Nile Virus vaccines are commonly required due to the severe health risks they pose to horses and their potential implications for public health. These diseases are prevalent in many areas and can lead to serious consequences if animals are not vaccinated.

Influenza, while a significant concern for horse populations, particularly in high-density settings like racetracks or boarding facilities, does not have the same level of enforced vaccination requirement in all contexts. Vaccination against influenza is often recommended but may not be mandated in the same way as the others in various competitions or events.

Thus, since influenza is more situation-dependent and often recommended rather than strictly required, it is the correct answer to indicate which disease is not universally mentioned as a vaccination requirement for horses.