Parvovirus shows up in regional wastewater

Wastewater monitoring is picking up human parvovirus B19 in parts of Northern California, adding one more virus to the region’s spring surveillance picture. WastewaterSCAN, a national monitoring program, shows parvovirus detections in recent data from sites including San Jose, Sacramento, Palo Alto, Redwood City and San Francisco-area plants. (data.wastewaterscan.org) CDC has said parvovirus B19 activity increased in the United States, and the agency issued a health advisory on August 13, 2024, to alert clinicians and public health officials. (cdc.gov) The virus is best known for causing “fifth disease,” a generally mild illness that can bring fever, runny nose, rash and joint pain, especially in children. (cdc.gov) ### What exactly is showing up in wastewater? WastewaterSCAN tracks genetic material from multiple pathogens in sewage samples, and its national dashboard currently lists parvovirus among monitored viruses. A site listing on the dashboard includes Northern California plants serving San Jose, Sunnyvale, Palo Alto, Redwood City, Sacramento and San Francisco. (data.wastewaterscan.org) Northern California media reports this week described the regional readings as showing parvovirus in wastewater across Bay Area and Sacramento-area communities. The dashboard itself is a surveillance tool, not a case count, and CDC says there is no routine national surveillance system for parvovirus B19 and the disease is not nationally notifiable. (publichealth.lacounty.gov) ### Is this the same “parvo” people know from dogs? CDC says parvovirus B19 infects humans, while canine parvovirus is a different virus. In people, B19 most commonly causes fifth disease, which can include the “slapped cheek” facial rash seen in children. (data.wastewaterscan.org) About 1 in 4 people who get infected have no symptoms, according to CDC. When symptoms do appear, the agency lists fever, headache, cough, sore throat, runny nose, rash, joint pain and muscle aches among the common signs. ### Who faces the biggest risks from parvovirus B19? CDC says most infections are mild for otherwise healthy children and adults. (usatoday.com) The agency also says complications can be more serious for people with blood disorders such as sickle cell disease or thalassemia, for people with weakened immune systems, and during pregnancy. Pregnancy guidance updated by CDC on December 17, 2025, says infection early in pregnancy can slightly increase the risk of miscarriage and can cause blood, heart or liver problems in the fetus. (cdc.gov) The Society for Maternal-Fetal Medicine said in an August 27, 2024 update that acute infection in pregnancy can be associated with severe fetal anemia, nonimmune hydrops and fetal demise. ### How does parvovirus B19 spread? CDC said in its 2024 health advisory that parvovirus B19 is a seasonal respiratory virus transmitted through respiratory droplets, including from people who do not have symptoms. The advisory cited increased test positivity and reports of clusters of complications among pregnant people and people with sickle cell disease during the 2024 rise in activity. (cdc.gov) That means the precautions are familiar ones. The Society for Maternal-Fetal Medicine says prevention steps include wearing a mask, washing hands, cleaning frequently touched surfaces, avoiding sharing food and drinks, limiting contact with sick people, and covering coughs and sneezes. (cdc.gov) ### What should pregnant people do if they think they were exposed? CDC says pregnant people who develop a new rash or joint pain, or who know they were exposed to someone with parvovirus B19, should contact an obstetrician or other healthcare provider. A blood test can help show whether someone has immunity, a recent infection or a past infection, the agency says. (publichealth.lacounty.gov) The CDC guidance says clinicians may recommend added prenatal visits, blood tests and ultrasound scans after infection during pregnancy. The Society for Maternal-Fetal Medicine says routine screening is not recommended for all pregnancies, but serologic testing should be considered after confirmed exposure or when symptoms are consistent with parvovirus B19 infection. (assets.noviams.com) ### What comes next in the Northern California monitoring? WastewaterSCAN updates its dashboard on a rolling basis, and Santa Clara County’s public health department links residents to that respiratory-virus wastewater data for local context. (cdc.gov) For now, the most concrete next step for residents with symptoms, pregnancy concerns or immune-related risk factors is to check with a healthcare provider and follow updated CDC guidance. (publichealth.santaclaracounty.gov)