infectious diseases
West Nile Virus
Key Points
West Nile virus is spread by among birds and transmitted to humans by the bite of an infected mosquito. Most patients have mild or no symptoms, but some develop a severe infection involving the central nervous system. Diagnosis is by serologic testing for West Nile virus–specific IgM or by plaque reduction neutralization tests demonstrating a significant rise between acute and convalescent IgG pairs. Patients who develop severe infection should be closely monitored for elevated intracranial pressure, inability to protect their airway, and respiratory failure requiring mechanical ventilation. 