What are the key clinical features to consider when diagnosing West Nile Virus in a patient presenting with febrile illness?

When diagnosing West Nile Virus (WNV) in a patient presenting with a febrile illness, key clinical features to consider include an acute onset of fever accompanied by headache, malaise, and myalgia. These symptoms often resemble a nonspecific viral syndrome but may also include rash, lymphadenopathy, and gastrointestinal symptoms such as nausea and vomiting. Neurological manifestations are critical to identify, as WNV can progress to neuroinvasive disease characterized by meningitis, encephalitis, or acute flaccid paralysis, which present with altered mental status, neck stiffness, muscle weakness, or paralysis. The presence of these neurological signs in a febrile patient, especially with a history of exposure to mosquito bites in endemic areas, should raise suspicion for WNV infection. Laboratory confirmation through serology or PCR is essential for diagnosis, but clinical suspicion is guided primarily by these presenting features and epidemiological context ¹ (Guharoy et al., 2004; MacDonald and Krym, 2005; Sejvar, 2007).