Pierce County wastewater tests positive for monkeypox virus
Sep 29, 2025, 12:30 PM
A registered nurse measures out a monkeypox vaccine shot at a vaccination site. (Photo: Joe Raedle, Getty Images)
(Photo: Joe Raedle, Getty Images)
Wastewater in Pierce County returned positive results of clade 1 mpox virus, known as monkeypox, following testing on Sept. 24 by the University of Washington (UW) and Washington State Department of Health (DOH).
The Tacoma-Pierce County Health Department (THD) will work with DOH to increase wastewater testing to monitor the situation, THD announced.
Currently, there have not been any reported cases of monkeypox in Pierce County.
Two viruses can cause monkeypox: clade 1 and clade 2. THD noted that a vast majority of monkeypox cases in the U.S. are caused by the clade 2 virus.
Six cases of clade 1 monkeypox have been reported in the U.S. in people who have recently traveled to countries with current outbreaks of the virus, according to the Centers for Disease Control and Prevention (CDC).
U.S. cases remain isolated
At this time, there have not been sustained transmissions of clade 1 monkeypox reported in the U.S.
Due to the detection being found in wastewater, the identity or travel history of individuals with clade 1 monkeypox in Pierce County is unknown.
“This is a rare occurrence, and also a great example of how public health keeps a close eye on disease spread to assess risk and inform the community when needed,” Health Officer for Tacoma-Pierce County Dr. James Miller said. “The risk to the community from clade 1 mpox remains low. If you have symptoms of mpox, you should consult your healthcare provider.”
Wastewater testing is supplemental to traditional clinical disease reporting, which offers an additional approach to detecting monkeypox in the U.S. as early as possible.
Various ways monkeypox can spread
THD mentioned monkeypox typically spreads through close physical contact, which includes sexual contact, day-to-day household contact, and within healthcare settings. Both the clade 1 and 2 viruses spread in the same way and can be prevented using similar methods.
Monkeypox can cause rashes that look like bumps, blisters, or ulcers. These rashes can be on a small portion of an individual’s body or cover a larger area of the body. In some cases, people will have flu-like symptoms before a rash develops.
Most people can recover within two to four weeks, but the disease can be serious for children, pregnant women, or those with weakened immune systems.
THD warned people who have new rashes, sores, or other symptoms that could be monkeypox to avoid sex and other skin-to-skin contact and seek a healthcare provider.
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