Did West Nile virus rates go up in 2021 compared to the past?
West Nile virus is the leading cause of domestically acquired arboviral disease in the continental United States 1. In 2021, the number of cases reported rose significantly above the average levels observed in the previous decade 2.
What the research says
Surveillance data from the United States shows that West Nile virus activity was higher in 2021 than the median rate recorded from 2010 through 2020 2. This increase marks a notable shift from the typical patterns seen in prior years 2.
The virus remains the primary arboviral threat in the U.S., with the majority of cases historically occurring between April and September 1. While reports for 2022 and 2023 describe ongoing case counts, the specific upward trend noted for 2021 stands out against the backdrop of the preceding ten years 234.
What to ask your doctor
- How do current West Nile virus rates compare to the 2010-2020 median in my area?
- What symptoms should I watch for if I live in a region with high mosquito activity?
- Are there specific precautions I should take this year given the recent increase in cases?
This question is drawn from common patient questions about Infectious Disease and answered using cited medical research. We do not provide individualized advice.