June, 2025

The influenza season is coming to a close, and RSV detection rates have declined over the past month. However, detections of parainfluenza viruses (PIV) are beginning to increase.

Parainfluenza viruses (PIV) are classified into four types (1–4) and are a significant cause of upper respiratory tract infections across all age groups. Notably, PIV types 1–3 account for approximately one-third of lower respiratory tract infections in children under five years of age.

Each PIV type is associated with distinct clinical and epidemiological characteristics. Common symptoms include croup, bronchiolitis, pneumonia, otitis media, pharyngitis, coryza, and conjunctivitis. Seasonal trends vary by geographic region and virus type. In the Pacific Northwest, PIV types 1–3 typically circulate during the winter months, with PIV-3 frequently reappearing in the summer. PIV-4 infections are rare and tend to occur sporadically.

Transmission occurs via large respiratory droplets during close person-to-person contact. Viral shedding can vary in duration and may be prolonged. Reinfection is common throughout life.

Refer to www.cdc.gov/coronavirus/2019-ncov for the most recent updates.

Ordering information available here: https://depts.washington.edu/uwviro/.

View the UW Virology COVID-19 Dashboard for up to date testing numbers.

Follow the area’s epidemiological data each week on the UW Virology web site at https://depts.washington.edu/uwviro/respiratory-viral-epidemiology-data/.

 

Community detections: May, 2025

PCR Positives: