Current Year Data (2024)

Key points

  • ArboNET is a national arboviral surveillance system managed by CDC and state health departments.
  • These data are preliminary and subject to change.
  • Current season data are updated every one to two weeks during June through December.
  • Due to delays in reporting, state, territorial, and local health departments may have more up-to-date information than what is presented here.

View the data for West Nile

Data are current as of July 9, 2024.

*Total human disease cases includes neuroinvasive and non-neuroinvasive disease cases.

Limitations of ArboNET data

Surveillance data have several limitations that should be considered when using and interpreting the data.

  1. Under-reporting is a limitation common to all surveillance systems that rely on healthcare providers to consider the disease as a possible diagnosis in a patient, obtain the appropriate laboratory test, and report confirmed to public health authorities.
  2. Cases of mild illness (non-neuroinvasive disease) are more likely to be underreported compared to more severe disease (neuroinvasive) cases. The degree of underreporting varies by disease awareness and healthcare-seeking behavior in any area. Surveillance data for non-neuroinvasive disease should not be used to make comparisons of disease activity between different locations or over time.
  3. Surveillance data are reported by county of residence, not the location (county or state) of exposure.
  4. Non-human surveillance is conducted variably across the country. Absence of non-human activity reported to CDC should not be interpreted as no risk.
  5. There is a lag in case reporting to CDC and states and territories may publish surveillance data on different schedules than CDC.