Epidemiological analysis of African Swine Fever (ASF) in Catalonia: Dispersal dynamics, wildlife control and biosafety protection of the sector

Origin, chronology and characterization of the outbreak in Collserola

The confirmation of this outbreak of African swine fever represented a milestone for Spain as it was the first case of ASF in Spain since 1994, interrupting three decades of disease-free status in the European Union. The Official Veterinary Services of the Generalitat identified the emergency on November 26, 2025, after finding two fresh wild boar carcasses in Cerdanyola del Valles confirming the initial focus of African Swine Fever in wild boars. The samples analyzed by PCR at the Research Center Animal Health Research (IRTA-CReSA) were positive.

Sequencing identified that this DNA virus of the family Asfarviridae and gender Asfivirus is of genotype II. This pathogen so contagious cause high fever and lethal hemorrhage, but it doesn’t affect humans. The origin of the outbreak of ASF outside due to wild migration, being attributed to an accidental introduction from fomites. Its great stability allows it to persist for weeks, suggesting that it entered through food debris the remains of contaminated meat products discarded.

Epidemiological evolution in 2026: Dynamics of dispersion and monitoring

During the first half of 2026, the epizootic increased within the peri-urban forest belt of the Collserola mountain range and the Barcelona metropolitan area. Consolidated official data reveal that surveillance managed to contain the spread to an affected area of high risk. As of June 2026, 58 official outbreaks have been reported in Catalonia (3 primary and 55 secondary due to horizontal transmission), totaling 355 positive results for African Swine Fever confirmed in thirteen municipalities of Vallès and the surrounding forest, registering numerous cases of ASF accumulated.

The forest tracking strategy combines research for corpses with active surveillance of captures or killings. This effort has allowed for the processing of 7,538 biological samples with negative results. In the last week of June 2026, the analysis determined the detection of 11 new positive cases of swine fever, which raises the total of infected wild boars identified. The report of these new positive cases evidence of a stabilization in the speed of virus spread within the delimited area.

The new findings continue to be associated with skeletal remains or decomposed corpses in the forest. Furthermore, the systematic monitoring of wild boars of Collserola through vehicle collisions on the roads of Vallès Occidental, acts as a secondary indicator of the dispersal of diseased fauna, confirming positive results from injured wild boars.

Legal framework and restrictive measures: Resolutions of the Generalitat

The administrative response following the initial outbreak was implemented through Resolution ARP/4434/2025 and Resolution ARP/4435/2025. Both decreed strict access restrictions and established an initial infected zone of zero to six kilometers around the focus and a surveillance zone between six and twenty kilometers.

The evolution of the virus forced a review of the perimeter. Resolution ARP/709/2026 declared a new focus, unifying and expanding the high-risk infected zone, which includes municipalities such as Sant Cugat del Vallès, Rubí, Cerdanyola, Terrassa or Sabadell, and fully includes the Collserola natural park.

In this natural area, restrictions include a complete ban on leisure activities, hiking, running and cycling. Access to unpaved forest tracks is prohibited and visitors are required to disinfect footwear and vehicles with virucides. Visitors are also reminded of the obligation to immediately report any injured or dead animals to the Rural Agents Corps or by calling 112.

Wildlife population control: Technology and selective capture

To understand the current situation of the outbreak, population control is the cornerstone of interrupting the transmission cycle. The Catalan government launched a plan to drastically reduce the wild boar population, setting a target of capturing up to 12,000 boars in the quarantined areas. Antoni Mur, head of the Department’s wildlife service, explained at a press conference: “The goal is to reach absolutely zero wild boars in the area,” admitting that this is impossible, but emphasizing that “the maximum we can allow is one wild boar per square kilometer.”

To achieve this density, the authorities modernized the capture device on June 25, 2026. Nighttime surveillance was deployed using thermal drones and camera traps equipped with vandal-proof anchors at strategic crossing points, speeding up the confirmation of new positives cases in wild boars and the monitoring of wild herds in Collserola.

The effort relies on selective group traps, expanding from 18 to 100 capture stations. Population control drives are coordinated by forest rangers and local hunters with specific biosecurity training. Likewise, the rapid removal of remains is a priority to mitigate the environmental persistence of the virus. The GEK9 canine units and the GECA groups use 1,000 liters of concentrated virucidal disinfectant.

Biosecurity protocols in pig farms and the wild interface

The main risk is that the virus will cross the interface and penetrate commercial farms of domestic pig. This would halt sales. Therefore, mandatory enhanced biosecurity measures were imposed.

The industry implements protocols based on a four-layer technical defense system:

Biosafety Layer Technical Guidelines and Biosafety Requirements Layer 1: Access Control “All or nothing” filter. Change of clothes and footwear. Mandatory vehicle disinfection. Layer 2: Hygiene and Disinfection Washing with foaming alkaline detergents and virucidal disinfectants (UNE-EN 14675). Chapter 3: Internal Control Systematic water purification and hermetic management of corpses and by-products (SANDACH). Layer 4: Perimeter and Environment Clean perimeter strip and reinforced fencing to avoid physical contact with wild boars.

The urgency was highlighted by an audit conducted by the Research Institute of Hunting Resources (IREC) and the Ministry of Agriculture, Livestock and Fisheries (MAPA). The investigation, titled “A protocol for external biosecurity assessment against wildlife in intensive pig farms: Are we ready for African Swine Fever?” (https://doi.org/10.1016/j.prevetmed.2026.106888). 

The study revealed serious gaps. Only 22.5% of the fences were impenetrable to wild boar, 50.0% of the gates were ineffective, and the presence of swine was found in 47.5% of the field audits. This highlights the risk of the virus spreading between these areas. Domestic pigs and wild boars, become infected animals. Therefore, it has restricted animal transport of this species, prohibiting the movement of fodder from the affected area and requiring the heat treatment of cereals for feed.

Trade resilience and export regionalization

The trade repercussions affected foreign trade flows due to the suspension of exports under 121 bilateral protocols with some 40 countries outside the EU. Impact on the pig sector Catalan and the rest of Spanish pork focused on the export of pork and various fresh meat products produced to markets that feared the arrival of meat products or scraps carriers of the pathogen. Exports fell by only 14.0% in the first half of 2026 thanks to trade regionalization.

This trade volume was sustained through strategic agreements. The People’s Republic of China recognized the regional health measures, limiting the ban to the province of Barcelona and maintaining open imports from the rest of the country. Meanwhile, the agreement with the Philippines ensured the restoration of up to 85% of export business. Currently, the United States government is considering adopting a similar regional framework.

However, the defense of export sales was achieved at the cost of reducing prices in the domestic market. Livestock farmers are operating on negative margins; the Unió de Pagesos (UdP) estimates that an intensive farm needs to earn at least €165.3 per animal sold to be viable, a figure that is not being reached in the current situation.

Conclusions regarding the current situation of the ASF outbreak

The management of the disease in Catalonia demonstrates that, while the containment of wild boar populations in Collserola and Vallès has so far prevented the feared spread of the virus to commercial farms, the sector operates under significant economic and biosanitary vulnerability. The stabilization of the wild outbreak relies on technological and regulatory measures, but the financial viability of livestock farmers will depend on addressing the physical gaps identified by IREC and consolidating regional trade agreements that alleviate pressure on domestic market prices.

The role of nutrition in resilience against ASF

Beyond physical biosecurity measures, pig farms located in surveillance or risk zones benefit from nutritional reinforcement to support the animals’ immune response and digestive health during sanitary stress episodes. At AMBiotec, we work with phytobiotics and nutritional supplements designed to strengthen the resilience of swine as a complement to the existing management and biosecurity protocols on the farm. If your operation is in one of the affected areas, our technical team can help you determine which nutritional program best suits your current situation.

Frequently Asked Questions

What is the current state of global scientific research on the development of an effective vaccine against the African Swine Fever virus?

Currently, there is no globally authorized commercial vaccine, so control rests on biosafety. However, IRTA-CReSA is leading the development of the live attenuated prototype BA71ΔCD2 with cross-protection, and the ASFV-G-ΔI177L strain has limited approval in Vietnam.

How will the preventive declaration of a hunting emergency in other autonomous communities, such as Andalucía, affect internal commercial channels and biosecurity at the national level?

This measure prohibits restocking and allows for extraordinary captures and the use of night vision devices to reduce wild populations. This prevents the spread of the virus and the declaration of restricted areas under EU regulations, protecting the livestock and meat trade.

What will be the long-term ecological and biodiversity impacts on Collserola Park resulting from reducing the wild boar population to the historical minimum of one specimen per square kilometer?

The drastic reduction will alleviate the predation pressure on forest floor nesting species. However, the loss of their winter rooting will decrease the bare soil areas needed for the colonization and germination of pioneer herbaceous plants.