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As part of the internal investigation to determine the origin of the virus that caused the recent African swine fever (ASF) outbreak in Spain, the Catalan Department of Agriculture (DARPA) today presented the available results of the sequencing carried out by the IRB (Institute for Research in Biomedicine in Barcelona) at a press conference. Those present included Toni Gabaldón, ICREA Research Professor at IRB Barcelona and a renowned expert in phylogeny and comparative genomics; Cristina Massot, Secretary General of DARPA; and Òscar Ordeig, Catalan Minister of Agriculture.
Within the framework of this investigation, the IRB performed complete sequencing of the viruses isolated from the first two ASF cases reported on November 28, 2025, as well as of the 17 ASF strains present at IRTA-CReSA—both vaccine candidates and challenge strains—which includes all strains used by the laboratory in the last 12 months. Two strains that have not been used for more than five years and are currently frozen remain to be sequenced.
In addition to comparing the strain responsible for the recent outbreak with all those stored at the IRTA-CReSA facilities, the IRB also compared this strain with the public database containing more than 800 African swine fever (ASF) virus sequences from various countries worldwide. It is important to note that ASF is a large, highly stable DNA virus.
The strain isolated in the outbreak shows no similarity to either the sequenced strains at IRTA-CReSA or the more than 800 strains included in the public database. The sequence detected in the ASF outbreak in Spain exhibits 27 point mutations, as well as a significant deletion. This strain had not been previously described, so it has been assigned a new group, 29.
Within the lines of research to clarify the origin of the virus, the final word will come from the work that is being carried out at the Reference Center for African Swine Fever (ASF), located in the laboratory in Algete.
Knowledge of the genome is key to trying to determine the origin of the outbreak, but also to understanding the characteristics of the virus and, thus, being able to adjust control measures according to its lethality level and other relevant factors.
Regarding the containment of the outbreak, which remains the top priority, a total of 533 wild boars have been analyzed throughout Catalonia, of which 29 tested positive, all of them located in the core area. These 533 samples include animals from outside the 20 km buffer zone, dead wild boars reported by the public, and roadkill. The deployment of 400 personnel in the area remains in place, and an increase in the rate of captures is expected. Intensive negotiations with various countries are also ongoing to recover affected markets.
Finally, the importance of caution, coordination, and the involvement of all stakeholders in the sector have been emphasized, as well as the importance of maximizing biosecurity measures.
December 30, 2025/ 333 Staff.
