How did West Nile virus disease patterns change from 2009 to 2018?
West Nile virus is the leading cause of domestically acquired arboviral disease in the continental United States, with most cases happening between April and September 2. Surveillance data from 2009 to 2018 shows that the geographic and seasonal patterns of the disease have changed over this period 3.
What the research says
In South Dakota, the geographic distribution of cases shifted toward the eastern portion of the state during the 2009 to 2018 timeframe 6. Additionally, the virus began occurring earlier in the transmission season in more recent years compared to the initial epidemic 6.
This shift in patterns is linked to broader changes in how the virus spreads. The virus range continues to expand as land use patterns change, creating more habitable environments for the mosquito vector 4. In specific areas like Colorado, irrigated agriculture has been identified as an important risk factor that influences where the virus spreads 5. These environmental factors help explain why the disease patterns change from year to year and across different regions 4.
What to ask your doctor
- How might local land use changes or irrigation projects near my home affect my risk for West Nile virus?
- What signs should I look for to know if the mosquito season is starting earlier in my area?
- Are there specific monitoring programs in my county that track West Nile virus activity?
This question is drawn from common patient questions about Infectious Disease and answered using cited medical research. We do not provide individualized advice.