On Sept. 24, 2025, Washington State Department of Health (DOH) and the University of Washington detected clade I mpox virus (also called monkeypox virus) in Pierce County wastewater. After consultation with Centers for Disease Control and Prevention (CDC), Tacoma-Pierce County Health Department is working with DOH to increase wastewater testing to monitor the situation. At this time, no patients with clade I mpox have been reported in Pierce County.
Two types of virus cause mpox: clade I and clade II. The vast majority of mpox cases in the United States have been caused by clade II mpox. According to CDC, six cases of clade I mpox have been reported in the United States in people who had recently traveled to countries with ongoing outbreaks. So far, there has not been sustained transmission of clade I mpox reported in the U.S.
Because this detection was in wastewater, the identity or travel history of any people with clade I mpox in Pierce County is not known. Wastewater testing complements traditional clinical disease reporting and offers an additional approach to detecting the presence of clade I mpox in the U.S. as early as possible. In partnership with DOH and CDC, we use wastewater testing data to monitor other communicable diseases in our community as well.
“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,” said Dr. James Miller, Health Officer for Tacoma-Pierce County. “The risk to the community from clade I mpox remains low. If you have symptoms of mpox, you should consult your healthcare provider.”
We encourage healthcare providers to consider mpox in patients with a rash that is consistent with mpox and to discuss the patient’s travel history to assess for the risk of clade I mpox. Healthcare providers and laboratories should report all cases of mpox to the Health Department. DOH and Tacoma-Pierce County Health Department will also share a health advisory with healthcare providers.
“We rely on astute clinicians as the eyes and ears of public health,” said Dr. Miller.
The mpox virus typically spreads during close physical contact, including through sexual contact, day-to-day household contact, and within healthcare settings in the absence of personal protective equipment. Both types of the virus (clade I and clade II) spread in the same way and can be prevented using the same methods.
Mpox can cause a rash that looks like bumps, blisters or ulcers. The rash can be on a small area of the body (including the genitals) or can cover a larger area of the body. Some people have flu-like symptoms before the rash develops.
Most people recover in 2–4 weeks, but the disease can be serious, especially for children and people who are pregnant or have weakened immune systems.
If you have a new rash, sores, or other symptoms that you think could be from mpox:
- Avoid sex and other skin-to-skin contact.
- See your healthcare provider. Remind them mpox may be circulating in the community.
If you don’t have a healthcare provider or insurance and need to get tested or treated for mpox, call us at (253) 649-1412.
A vaccine is available for people at higher risk of contracting mpox. Contact your healthcare provider to get vaccinated or see our website for more information and resources on getting vaccinated at a pharmacy.
About Tacoma-Pierce County Health Department: Tacoma-Pierce County Health Department’s mission is to protect and improve the health of all people and places in Pierce County. As part of our mission, the Health Department tackles known and emerging health risks through policy, programs, and treatment to protect public health. Learn more at tpchd.org.