How many people catch west nile virus every year?

The number of West Nile virus (WNV) cases in the United States varies from year to year. According to the Centers for Disease Control and Prevention (CDC), an average of 2,500 cases of WNV are reported each year in the United States. However, the number of cases can range from a few hundred to several thousand in any given year. The majority of WNV cases occur in the summer and early fall months when mosquitoes are most active.