Active Public Health Outbreaks in Oregon
Surveillance Report • November 30, 2025
Pertussis
Continued surge with case counts nearing historic highs.
E. coli O103
Active outbreak linked to raw milk cheese recall.
Measles
Virus detected in wastewater; clinical alert active.
Pertussis (Whooping Cough) Surge
Oregon is currently grappling with a sustained Pertussis outbreak that began in 2024 and has persisted through late 2025. Following a record-breaking year in 2024—which saw over 1,100 cases, the highest since 1950—transmission remains critically high. As of mid-2025, the state had already recorded 877 cases, putting it on track to potentially match or exceed the previous year's figures.
Health officials attribute the resurgence to "waning immunity" and a drop in vaccination rates post-pandemic. The outbreak is widespread but shows distinct geographical clustering.
Reported Cases by County (2024-2025 Peak Areas)
*Data reflects cumulative counts from the onset of the current surge.
Measles: The Silent Threat
While confirmed clinical cases remain low (only one confirmed case in Multnomah County for 2025 as of June), environmental surveillance suggests hidden transmission. The Oregon Health Authority (OHA) has issued alerts following the detection of the measles virus in wastewater samples.
- ! November 14, 2025: Alert issued after virus detected in Josephine County wastewater (sample from Oct 30).
- ! October 20, 2025: Virus detected in Marion County wastewater (sample from Oct 6).
E. coli O103 Outbreak
A multistate outbreak of Shiga toxin-producing E. coli O103 is currently active, linked to Twin Sisters Creamery raw milk cheese.
10 Total Cases: 9 in Washington, 1 in Oregon.
The Oregon patient reported consuming "Farmhouse" cheese. A Class I recall is in effect for all raw milk cheeses aged =60 days from this producer.
Respiratory Virus Surveillance (2025-2026 Season)
| Pathogen | Activity Level | Trend | Notes |
|---|---|---|---|
| Influenza | Low | Increasing | Early season activity; vaccination urged. |
| RSV | Low | Slow Rise | Hospitalization rate 0.4 per 100k (very low). |
| Avian Flu (H5N1) | Surveillance | Stable | First human case confirmed Nov 2024. No new human cases in late 2025. |
Data Sources: Oregon Health Authority (OHA) Weekly Reports, CDC FluView, and local public health advisories. Data current as of November 30, 2025.