Avian Influenza Trends in Spain and Portugal: Understanding the Recent H5N1 Surge
Europe is currently navigating a renewed surge of highly pathogenic avian influenza (HPAI), specifically the H5N1 subtype. Whereas the impact varies by region, recent outbreaks in Spain and Portugal highlight the ongoing challenge of managing a virus that affects wild birds, domestic poultry, and occasionally mammals. Understanding these patterns is crucial for biosecurity and public health monitoring.
- Portugal: Experienced a significant escalation in early 2025 with a major outbreak in Sintra.
- Spain: Recent detections include hundreds of dead storks near Madrid and a mink farm outbreak in Galicia.
- European Context: Over 700 detections were confirmed across 31 European countries between December 2024 and June 2025.
- Human Risk: Infections remain rare, though global monitoring continues.
Avian Influenza in Portugal: The Sintra Outbreak
Portugal’s battle with H5N1 escalated significantly in early January 2025. The country reported its first outbreak of the season at a large poultry farm in Sintra, which housed more than 55,000 laying hens.
To prevent further spread, authorities implemented immediate containment measures. These included the culling of infected flocks, strict movement restrictions, and the establishment of protection zones around the affected area. This response underscores the volatility of HPAI and the necessity of rapid intervention to protect the broader agricultural sector.
Spain’s Multifaceted Outbreaks: From Wild Birds to Mammals
Spain has faced diverse challenges with bird flu, affecting different species and regions across the country.
Wild Bird Mortality in Madrid
In December 2025, Spanish authorities detected four separate outbreaks among wild birds in the central Madrid region. Forestry agents collected hundreds of dead storks, with over a hundred deaths recorded in a single 24-hour window. These storks, migratory birds arriving from northern Europe, are believed to be the primary carriers of the virus. Despite the high mortality rate among wildlife, the Madrid regional government confirmed that no commercial poultry farms were affected and there was no serious risk to humans.
Mammalian Transmission in Galicia
The virus’s ability to jump species remains a point of concern. In October 2025, the H5N1 virus was detected during an outbreak at a mink farm in Spain’s Galicia region. Investigations into this incident confirmed mink-to-mink transmission, highlighting the virus’s adaptability.
Historical Human Case
While rare, human infection is possible. On September 27, 2022, the Ministry of Public Health of Spain notified the WHO of an HPAI H5N1 case involving an individual employed at a poultry farm.
The Broader European Landscape
The situation in the Iberian Peninsula is part of a larger, unprecedented surge across the continent. Between December 2024 and June 2025, more than 700 detections of HPAI were confirmed across 31 European countries. This surge affected both domestic birds and a wide array of wild species.
In Germany, detections have been reported in poultry and various mammals, including red foxes, domestic cats, and Eurasian otters, as well as wild birds like swans, geese, and ducks. The European Food Safety Authority (EFSA) and the European Centre for Disease Prevention and Control (ECDC) attribute this resurgence to several factors:
- Seasonal Migrations: Migratory birds carry the virus across borders.
- Environmental Factors: Colder weather patterns.
- Biosecurity Gaps: Outdoor access for poultry significantly increases exposure to infected wild birds.
Public Health Risk and Global Context
For the general public, the risk of contracting bird flu remains low. However, global health organizations maintain close surveillance. Between December 2024 and June 2025, 42 human cases were reported globally, with detections in the United Kingdom, Mexico, India, China, Cambodia, and Bangladesh.
Frequently Asked Questions
Is there a high risk to humans in Spain and Portugal?
No. Based on the behavior of the current outbreaks, health authorities in Madrid and across Europe have stated there is no serious risk to human health, as transmission to people remains rare.
How is the virus spreading so quickly?
The spread is primarily driven by the migration of wild birds and gaps in biosecurity, particularly when domestic poultry have outdoor access to environments where wild birds congregate.
Looking Ahead
The continued detection of H5N1 in diverse species—from storks in Madrid to minks in Galicia—emphasizes the need for vigilant biosecurity and cross-border cooperation. As migratory patterns continue to shift, the focus remains on protecting commercial poultry and monitoring the virus’s potential for further cross-species transmission to ensure public health safety.