West Nile Virus Disease 
West Nile virus (WNV) is the leading cause of mosquito-borne disease in the continental United States. It is most commonly spread to people by the bite of an infected mosquito. Cases of WNV occur during mosquito season, which starts in the summer and continues through fall. There are no vaccines to prevent or medications to treat WNV in people. Fortunately, most people infected with WNV do not feel sick. About 1 in 5 people who are infected develop a fever and other symptoms. About 1 out of 150 infected people develop a serious, sometimes fatal, illness. You can reduce your risk of WNV by using insect repellent and wearing long-sleeved shirts and long pants to prevent mosquito bites.

West Nile Virus disease is monitored to prevent and control outbreaks.

In 2022, the rate per 100,000 of West Nile Virus Disease in Alachua County was 0 compared to Florida at 0. The line graph shows change over time when there are at least three years of data.

Links:   Healthy People 2030|Other Resource
Measure Type 
10 Year Report
View 10 Year Report
Alachua County
Click on county name or “Florida” in the legend to hide or show the county or state.

At least 51 counties must have rates greater than zero for a quartile map to be displayed.

West Nile Virus Disease, Rate Per 100,000 Population, Single Year
Data YearCountDenomRateMOVCountDenomRateMOV
FLHealthCharts.gov is provided by the Florida Department of Health, Division of Public Health Statistics and Performance Management.
Data Source: Florida Department of Health, Bureau of Epidemiology
12/3/2023 9:08:05 AM
Data Note(s)
  • Merlin Codes 06630, 06631
  • This disease became reportable on June 9, 2003. The first full year of data collection is 2004. Cases occurring in previous years may have been retrospectively identified after becoming reportable. Counts and rates include confirmed and probable cases of West Nile Virus Neuroinvasive Disease (Merlin code 06630) and West Nile Virus Non-Neuroinvasive Disease (Merlin code 06631).
  • Data presented here are from Merlin, Florida's web-based reportable disease surveillance system. Note that any data prior to 1992 are not maintained in Merlin and should be interpreted with caution.
  • Data in this report are aggregated by the date the case was reported to the Bureau of Epidemiology, Florida Department of Health. Cases are assigned to Florida counties based on the county of residence at the time of the disease identification, regardless of where they became ill or were hospitalized, diagnosed, or exposed.
  • Reports for reportable disease data are produced weekly, monthly, and annually. To access these reports, visit Surveillance Publications. More detailed information on interpreting data can be found in the introduction section of the annual reports. For questions, please contact the Bureau of Epidemiology at (850) 245-4401.
  • This is primary, quantitative data.
  • All population-based rates are calculated using July 1 Florida population estimates from the Florida Legislature, Office of Economic and Demographic Research.
  • Chart will display if there are at least three years of data.
  • Multi-year counts are a sum of the selected years, not an average.
  • Quartiles are calculated when data are available for at least 51 counties.
  • MOV - Measure of Variability: Probable range of values resulting from random fluctuations in the number of events. Not calculated when numerator is below 5 or denominator is below 20, or count or rate is suppressed. The MOV is useful for comparing rates to a goal or standard. For example, if the absolute difference between the county rate and the statewide rate is less than the MOV, the county rate is not significantly different from the statewide rate (alpha level = 0.05). When the absolute difference between the county rate and the statewide rate is greater than the MOV, the county rate is significantly different from the statewide rate. MOV should not be used to determine if the rates of two different counties, or the county rates for two different years, are statistically significantly different.
  • Denom - abbreviated for denominator.
  • Population estimates are not available for persons whose county of residence is unknown. Given this, the denominator and associated rate are not available.
  • * - Indicates the county rate is statistically significantly different from the statewide rate.