U.S. Mpox Wastewater Data

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Mpox Wastewater Data

Wastewater sites across the United States are testing for traces of the virus that causes mpox. Wastewater data are updated every Friday with the previous week's data, which allows for data to be reviewed for accuracy. Data may change as more reports are received.

Laboratory tests are used for monitoring wastewater for the virus that causes mpox. These tests can tell us if genetic material from the virus (viral DNA) is present in untreated community wastewater. Based on the results, each wastewater site is assigned a detection category:

  • No recent detection means there is no recent evidence from wastewater data that mpox is spreading in the local community. However, wastewater monitoring may not detect the virus if there are very few mpox cases in a community.
  • Detection means there is evidence of some mpox infections in the community.
  • Persistent detection means mpox infections may be staying stable or increasing in the community.

Learn more about how mpox spreads, how to prevent mpox, and about the current situation of mpox outbreaks in the US and around the world.

Types of Testing for Mpox in Wastewater 

Currently, testing methodology for the virus that causes mpox varies between wastewater sites. Some sites are testing for specific types (or clades) of the virus. Some sites use tests that detect clade II only. In December 2024, some sites began using tests that detect clade I only, with CDC’s national contract beginning testing on January 2, 2025. Other sites use non-clade specific tests that can detect both clades of the virus, though they do not distinguish between clade I and clade II. Each site may use one or more tests.

Wastewater detections of the virus that causes mpox in the past 4 weeks, United States

Mpox Testing Summary

Summary of all testing results for each wastewater testing site in the past four weeks. Each site may use one or more types of tests to detect the virus that causes mpox. See definitions for each detection category.

Mpox Results by Test Type

Explore each tab to see testing results based on the type of testing (non-clade specific, clade I, or clade II). Each dot on the map represents a wastewater sampling site.

Detection Categories:

  Persistent detection: The virus that causes mpox was detected in more than 80% of samples in the past 4 weeks AND the most recent detection was within the past 2 weeks.

  Detection: The virus that causes mpox was detected in 1% to 80% of samples in the past 4 weeks AND the most recent detection was within the past 2 weeks.

  No recent detection: The virus that causes mpox was not detected in any samples in the past 2 weeks.

  No recent data: Fewer than 3 samples were submitted in the past 4 weeks.

Wastewater sites across the United States are testing for the virus that causes mpox (MPXV).

Clade-specific Testing in Wastewater:

There are two distinct genetic clades of the virus that causes mpox: clade I and clade II. Each clade of the virus has subclades, clade Ia and clade Ib; clade IIb. Not all clade-specific wastewater assays will be able to detect or distinguish between clades or subclades (i.e. subtypes).

If a site has a detection using a non-clade specific test but does not have a detection using a clade II test, this does NOT necessarily indicate that clade I is present. Instead, it highlights a need for further public health investigation.

There is currently an outbreak of clade I mpox in Central and Eastern Africa that has also caused some travel-associated cases in other countries. Clade II mpox cases continue to spread at low levels in many countries around the world, including the United States.

Data Notes

  • Each dot on the map represents a wastewater site. A site can represent all or part of a sewershed, which is the geographic area contributing wastewater to a sampling location. Sewersheds may cross county or state boundaries.
  • Samples from some sites are tested for the virus that causes mpox at different laboratories that may use different collection and testing methods. These sites have more than one dot on the map with the same sewershed number followed by a different letter. These sites may have different detection categories for the different dots.
  • States or territories that do not test for MPXV or have not reported data in the past two months will not have sites displayed on the map. Sites that have not submitted at least 3 MPXV samples in the previous 4 weeks are labeled as 'No recent data'.
  • Not all communities report wastewater data to CDC. Participation is voluntary. Wastewater samples are collected from sewer systems, so communities that rely primarily on septic systems are not represented.
  • Data are plotted in the ZIP code of the sampling location, so dots on the map do not correspond exactly to sampling locations.

MPXV Metric Calculation:

  • A positive detection at an individual sampling site reflects whether the virus was detected within the samples collected over the previous 4 weeks.  An individual sampling site is typically a wastewater treatment plant but may be a location in the sewershed before wastewater enters the treatment plant.
  • All samples collected over the previous 4 weeks at a site are included in the percent detection calculation. For each MPXV testing type (clade I, clade II, non-clade specific), the number of positive samples at a site is divided by the number of total samples to calculate the percent of detections at a site.
  • The percent of detections at a site for each MPXV testing type are then used to categorize the site into one of 4 categories: persistent detection, detection, no recent detection, or no recent data. Most recent date of detection by site and MPXV testing type is used to determine if the site had a detection in the previous 2 weeks. See definitions for each detection category.
  • MPXV laboratory detections reported on CDC's wastewater dashboard may, in some cases, fall below the stated limit of detection for the assay. Limits of detection are calculated by the laboratory doing the analysis and are specific to the assay and laboratory methodology.
  • A site may appear in more than one detection category if samples from the site are tested for MPXV at different laboratories or if samples from a site are tested using more than one test type.

Data Sources