What symptom is most commonly associated with West Nile Virus infection?

Flu-like symptoms are the most commonly associated with West Nile Virus infection because they encompass a range of signs that reflect the body's response to the virus. These symptoms typically include fever, headache, body aches, fatigue, and sometimes nausea or vomiting. The presentation of these symptoms is a hallmark of many viral infections, including West Nile Virus, as the immune system reacts to the virus's presence.

While severe headaches, skin rash, and joint pain can occur with West Nile Virus, they are not as prevalent as the general flu-like symptoms. Severe headaches may indeed be associated with more serious outcomes, but they do not represent the most common experience of individuals infected with the virus. Similarly, skin rash and joint pain are less typical and are often seen in particular subgroups or in more severe cases, rather than as general symptoms for the vast majority of infections. Therefore, the presence of flu-like symptoms stands out as the primary indication of West Nile Virus infection.