Latest developments on the African swine fever outbreak in Spain: The source of this outbreak is highly suspected to be a laboratory leak. The main reasons are as follows:
1. Abnormal viral genotype
Sequencing results from the National Reference Laboratory in Madrid indicate that the virus strain discovered in this case differs from the wild strains currently circulating in Eastern Europe, Poland, or Italy. Instead, this strain bears a high degree of similarity to the “Georgia 2007” strain. This particular strain is primarily found in laboratories for vaccine development and scientific research and is no longer prevalent in the local natural environment.
2. A laboratory researching African swine fever happens to be located near the outbreak site.
The Catalan government has identified a research center specializing in major swine diseases—including African swine fever—located within the quarantine zone near Barcelona. Public records indicate this institution was previously designated by the World Organisation for Animal Health as one of its “Research Centers for Swine Fever Diseases.” Situated within the 6-kilometer quarantine perimeter and not far from where the cases were detected, this center has become a key focus for investigation.
3. The original hypothesis of “contaminated meat products carrying pathogens” has been challenged by data.
Early local officials suggested that the virus might have been introduced through contaminated meat products, which were then consumed by wild boars scavenging through garbage, leading to transmission. However, subsequent genetic sequencing reports indicated that this virus strain did not appear to originate from any EU country currently experiencing ongoing ASF outbreaks and did not match the prevalent strains in circulation. Consequently, the Ministry of Agriculture decided to focus its investigation on whether the virus originated from research strains.
On December 5, 2025, Spain's Ministry of Agriculture publicly stated that “it is unlikely that the virus originated from animals or animal products in EU countries currently experiencing African swine fever outbreaks”; “this finding does not rule out the possibility of its origin in a biosafety laboratory facility.”
To date, relevant authorities have launched investigations into five laboratories, though the Ministry of Agriculture has not publicly disclosed their names in its official documents. The Catalan regional government has specifically ordered an investigation into the animal disease research center within the quarantine zone. The results of these investigations have not yet been released.
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1. Abnormal viral genotype
Sequencing results from the National Reference Laboratory in Madrid indicate that the virus strain discovered in this case differs from the wild strains currently circulating in Eastern Europe, Poland, or Italy. Instead, this strain bears a high degree of similarity to the “Georgia 2007” strain. This particular strain is primarily found in laboratories for vaccine development and scientific research and is no longer prevalent in the local natural environment.
2. A laboratory researching African swine fever happens to be located near the outbreak site.
The Catalan government has identified a research center specializing in major swine diseases—including African swine fever—located within the quarantine zone near Barcelona. Public records indicate this institution was previously designated by the World Organisation for Animal Health as one of its “Research Centers for Swine Fever Diseases.” Situated within the 6-kilometer quarantine perimeter and not far from where the cases were detected, this center has become a key focus for investigation.
3. The original hypothesis of “contaminated meat products carrying pathogens” has been challenged by data.
Early local officials suggested that the virus might have been introduced through contaminated meat products, which were then consumed by wild boars scavenging through garbage, leading to transmission. However, subsequent genetic sequencing reports indicated that this virus strain did not appear to originate from any EU country currently experiencing ongoing ASF outbreaks and did not match the prevalent strains in circulation. Consequently, the Ministry of Agriculture decided to focus its investigation on whether the virus originated from research strains.
On December 5, 2025, Spain's Ministry of Agriculture publicly stated that “it is unlikely that the virus originated from animals or animal products in EU countries currently experiencing African swine fever outbreaks”; “this finding does not rule out the possibility of its origin in a biosafety laboratory facility.”
To date, relevant authorities have launched investigations into five laboratories, though the Ministry of Agriculture has not publicly disclosed their names in its official documents. The Catalan regional government has specifically ordered an investigation into the animal disease research center within the quarantine zone. The results of these investigations have not yet been released.
Disclaimer: Some articles and materials are sourced from the internet. The original sources have been clearly indicated, and all copyrights belong to the original authors. The content is provided for reference only. If any infringement of the original author's rights occurs, please contact us promptly to request removal.