Active Public Health Outbreaks in Maine: November 2025 Status Report
As of late November 2025, Maine is navigating a complex public health landscape characterized by a "syndemic" of respiratory viruses, a persistent surge in pertussis (whooping cough), and specific localized alerts for tuberculosis and foodborne pathogens. While the state has successfully avoided the measles outbreaks affecting other regions, vector-borne disease activity remains historically high even late into the season.
?? High Alert / Active Outbreaks
- Pertussis: Statewide surge; cases double previous year's baseline.
- Respiratory Viruses: RSV and Flu rising sharply in wastewater.
- Avian Influenza (H5N1): Active in wild birds (York/Cumberland counties).
- Infant Botulism: 1 confirmed case linked to national formula recall.
??? Monitored / Controlled
- Measles: 0 confirmed cases despite national outbreaks.
- Tuberculosis: 3 active cases (Greater Portland); isolated, no wider threat.
- COVID-19: Moderate activity; lower than 2023 peaks.
1. Respiratory Virus Season (The "Tripledemic" Watch)
Maine is currently entering the peak respiratory virus season. Surveillance data from November 2025 highlights a divergence between wastewater signals (which are leading indicators) and clinical reported cases. While hospitalizations remain manageable, wastewater concentrations for RSV and Influenza are showing a sharp upward trajectory in the Northeast region.
| Pathogen | Current Trend (Nov 2025) | Data Source Contrast |
|---|---|---|
| RSV | ? Increasing Rapidly | Wastewater levels rising faster than ED visits (pediatric focus). |
| Influenza (Flu) | ? Increasing | Early season uptick; lagging behind RSV trends. |
| COVID-19 | ? Stable / Moderate | Wastewater shows "medium" load; hospitalizations remain low. |
2. The Pertussis (Whooping Cough) Surge
Unlike the seasonal respiratory viruses, Pertussis has been spreading at epidemic levels throughout 2024 and into late 2025. Maine CDC reports indicate a significant "catch-up" phenomenon post-pandemic, with waning immunity and lower vaccination rates contributing to the spread.
Pertussis Case Comparison (Year-to-Date)
*Data reflects confirmed cases reported by Maine CDC. The 2025 surge is particularly affecting teenagers (43% of cases) and children under 5.
3. Vector-Borne & Environmental Alerts
While late November typically signals the end of mosquito activity, tick-borne diseases remain a threat whenever temperatures are above freezing. Additionally, environmental surveillance has detected Avian Influenza in local wildlife.
Ticks: A Record Year
2025 has been a record-breaking year for tick encounters. As of October/November, cases of Lyme disease, Anaplasmosis, and Babesiosis have all surpassed 2024 levels.
Anaplasmosis: >1,200
Babesiosis: >320
Avian Influenza (H5N1)
Status: Detected in wild birds (Canada geese, hawks, owl) in York and Cumberland counties.
Risk: High for domestic poultry; Low for humans. No human cases reported in Maine to date.
4. Isolated Public Health Incidents
Beyond widespread outbreaks, Maine is managing specific, contained health events:
- Tuberculosis (TB): Three active cases were confirmed in the Greater Portland area in September 2025. Officials emphasize these are isolated incidents and not a shelter-based outbreak, countering local rumors.
- Infant Botulism: Maine has reported 1 case associated with the multistate outbreak linked to "ByHeart" powdered infant formula. This is part of a larger investigation involving 37 infants across 17 states.