H5N1 Avian Influenza spreads with three new outbreaks in Castilla y León and Madrid
Epidemiological situation update (01/10/2025)
The Ministry of Agriculture, Fisheries and Food has notified today, 1 October 2025, three new outbreaks of Highly Pathogenic Avian Influenza (HPAI) H5N1 on poultry farms in Spain. Two of these outbreaks have been detected in Castilla y León and the third in the Community of Madrid. With these detections, the total number of HPAI outbreaks in poultry in Spain in 2025 rises to nine. All indications suggest that the two farms in Valladolid are secondary foci (originating from the outbreak at the nearby Olmedo farm housing 760,000 laying hens) and that the Madrid case is a primary focus (meaning the virus was introduced via wild birds).
Valladolid and Madrid affected by the H5N1 strain
The veterinary authorities of the Junta de Castilla y León have confirmed two outbreaks in the province of Valladolid. These farms are located within the 3 km radius of the HPAI H5N1 outbreak previously confirmed on 19 September in Olmedo (Valladolid).
The affected farms in Valladolid hold significant flocks: the first, located in Olmedo, houses 14,000 free-range hens, and the second, located in the municipality of Aguasal, accommodates 88,000 laying hens. Suspicion arose on 29 September following the detection and reporting of increased mortality to the Official Veterinary Services (OVS). It has been determined that both farms maintain epidemiological links with the initial Olmedo outbreak and have therefore been classified as secondary foci.
Additionally, an outbreak has been notified in the Community of Madrid, located in the municipality of Valdemoro. This is a large-scale operation housing 450,000 laying hens. Suspicion at Valdemoro began on 30 September due to a slight increase in mortality. In contrast to the Valladolid cases, no epidemiological link has been detected at the Valdemoro farm with previous outbreaks; the most likely route of H5N1 virus introduction is considered to be direct or indirect contact with wild birds.
With these three outbreaks, the total now stands at nine cases on poultry farms in Spain so far in 2025. In all three cases, the Central Veterinary Laboratory (LCV) in Algete, acting as the National Reference Laboratory, has confirmed the presence of HPAI subtype H5N1.
Stringent control measures to halt the spread
The OVS of Castilla y León and the Community of Madrid have immediately implemented control measures in accordance with Commission Delegated Regulation (EU) 2020/687. These include:
- Immediate standstill of the affected holdings and those located within the restricted zone from the date of suspicion (29 and 30 September 2025, respectively).
- Culling of birds on the affected holdings, and the official disposal of carcasses, feed and other fomites capable of transmitting the virus, in accordance with SANDACH regulations.
- Establishment of a restricted zone around the three outbreaks, comprising a 3 km protection zone and a 3–10 km surveillance zone.
The Valladolid restricted zone encompasses 15 commercial farms. The restricted zone established around Valdemoro extends into part of the province of Toledo (Castilla-La Mancha), where two commercial holdings have been identified.
Alert over spread in wild birds
With these new cases, the 9 HPAI outbreaks in poultry detected in Spain in 2025 are distributed across Badajoz (1), Toledo (1), Huelva (2), Guadalajara (1), Valladolid (3) and Madrid (1).
It is worth noting that since the start of the current season (1 July 2025), 40 outbreaks in wild birds have been detected across nine autonomous communities, along with 2 outbreaks in captive birds.
Poultry operators are advised to maintain and reinforce biosecurity measures and passive surveillance, reporting any suspicion to the OVS, such as drops in water/feed consumption, reduced egg production, or elevated mortality.
Finally, the authorities remind the public that the virus is not transmitted to humans through cooked poultry meat, eggs or processed derived products, although it is advisable to minimise unnecessary contact with dead birds or those showing clinical signs in the field.
The daily follow-up by the authorities can be consulted in the official MAPA list of Latest registered notifications of notifiable animal diseases in Spain.
Source: Ministry of Agriculture.
For further information on Avian Influenza:
-. News on Vaccination of poultry farmers and personnel in contact with production birds to prevent zoonosis risks.
-. News on Vaccination of production birds to prevent AI outbreaks
-. Triple avian influenza alert: Portugal, Spain and Germany confirm cases on poultry farms. (5 Sept 2025)
-. Avian Influenza on NeXusAvicultura
Tracking of Avian Influenza cases on poultry farms in Spain in 2025:
-. First case of 2025 (18 July, Extremadura): Alert over an Avian Influenza outbreak on a 7,000-turkey farm in Extremadura
-. Second case (28 July, Toledo): Second AI outbreak detected, this time in breeder birds in Toledo
-. Third case (1 Sept., Huelva): The spectre of H5N1 returns to Andalusia: 8,500 turkeys culled due to avian influenza in Huelva.
-. Fourth case (8 Sept., Guadalajara): Spain records its fourth AI outbreak of 2025, this time on a breeder farm in Guadalajara
-. Fifth case (9 Sept., Huelva): H5N1 positive confirmed on the 8,400-bird poultry farm in Valverde del Camino, Huelva, Andalusia
-. Sixth case (19 Sept., Valladolid): H5N1 AI detected on a 760,000 laying hen farm in Valladolid
-. 7th, 8th and 9th cases (1 Oct., Valladolid and Madrid): 552,000 laying hens affected by three new AI outbreaks in Madrid and Valladolid
-. Furthermore, on 2 September 2025, Portugal confirmed an H5N1 outbreak at the largest meat duck fattening farm on the Iberian Peninsula, specifically a poultry complex of 257,650 meat ducks in the locality of Samora Correia, near Lisbon, in the freguesia of Santo Estevão, concelho of Benavente, district of Santarém.