Wastewater surveillance may complement other existing human surveillance systems to monitor influenza. Wastewater data cannot determine the source of influenza A viruses. Detections could come from a human or from an animal (like a bird) or an animal product (like milk from an infected cow).

About CDC’s Wastewater Program (NWSS)

How Wastewater Monitoring Works

Wastewater Data for Avian Influenza A(H5)

H5 detection in wastewater in the past week

This interactive map shows current site-level data for avian influenza A(H5) viral RNA detections in wastewater. Each dot on the map represents a wastewater sampling site. For each site, results are reported as “H5 Detection” when any of the samples were positive during the week reported. When avian influenza A(H5) virus is not detected in any of the samples, then the site is classified as “No Detection.” All data are preliminary and may change as more reports are received. Data will be updated on this site every Friday, based on data submitted to CDC by the end of the day on the previous Wednesday.

Testing for influenza A(H5) virus in community wastewater can provide a signal that animals or humans may be infected with the virus. Wastewater testing cannot tell us whether the virus comes from animals, an animal product (like milk from an infected cow), or humans. Detections of influenza A(H5) virus in wastewater do not necessarily mean that humans in the community are infected with the virus.

When wastewater testing shows a detection, public health and agriculture partners investigate to better understand what may be contributing to the detection and whether any public health actions should be taken.

Current Outbreak: A subtype of influenza A(H5), known as avian influenza A(H5N1), is spreading in wild birds worldwide. This is causing outbreaks in poultry and U.S. dairy cows with several recent human cases in U.S. dairy and poultry workers. No human-to-human spread has been identified in the United States. Wastewater testing for influenza A(H5) virus does not tell us whether H5N1 or another subtype of H5 is present in the wastewater.

Learn more about the current outbreak of avian influenza (H5N1) at H5 Bird Flu: Current Situation.
Learn how you can reduce your risk of getting avian influenza (H5N1) from infected animals.

Click on the legend below to see detections.

H5 detection in wastewater in the past six weeks

This searchable table shows site-level data for avian influenza A(H5) viral RNA detections in wastewater for the past six weeks. The date in the column header is the last day for that week of sample collection. The table shows if:

+ H5 was detected at the site

– H5 was not detected at a site

No Data No samples were taken for that site or no data is available for that site

To filter for sites with a recent H5 detection, type + in the search bar.

Wastewater surveillance may complement other existing human influenza surveillance systems to monitor influenza. Avian influenza A(H5) virus data in wastewater include data collected and reported to CDC’s National Wastewater Surveillance System (NWSS) by:
- A CDC contract partner (Verily Life Sciences, LLC).
- An academic partner group (WastewaterSCAN): These data were collected as part of a partnership between Stanford University, Emory University, and Verily funded philanthropically through a gift to Stanford University. Find more about these and use at: wastewaterscan.org/about/#15.
- State and local public health departments: Data from state and local health departments were reported through the NWSS program and funded through the Epidemiology and Laboratory Capacity for the Prevention and Control of Emerging Infectious Diseases (ELC) Cooperative Agreement.
Each wastewater sampling site can represent all or part of a sewershed, which is the geographic area contributing wastewater to a sampling location. Sewersheds can encompass populations of varying sizes and may cross county or state boundaries.
In each wastewater sampling site, wastewater sampling and testing occurs one or more times during the week.
See Data Methods to learn more about how data is calculated and methodology.