The so-called “sandwich theory,” which suggests that the origin of the ASF virus outbreak was contaminated food, has gained credibility following the publication of the initial document by the scientific committee commissioned by the Spanish Government. Experts have explicitly ruled out the possibility of sabotage, natural transmission, or an accidental laboratory leak, considering the sandwich hypothesis “coherent” and “compatible” with the facts.
The report definitively rules out that the outbreak was a consequence of a leak at IRTA-Cresa, a speculation that had circulated months ago. Complementary analyses carried out by independent organizations found no genetic match between the virus isolated in the Cerdanyola outbreak zone and the viruses used in experimental activities at the research center. This result comes shortly after a study commissioned by the Catalan Government reached similar conclusions.
The committee of investigators points out that the sandwich theory is compatible with several key epidemiological elements observed in Catalonia. These include the isolated appearance of the focus, without continuity with previously affected areas; the absence of intermediate foci in neighboring countries; and the location of the outbreak in an environment of high human mobility and a dense network of road and rail infrastructure.
The available genetic information does not allow the geographical origin of the outbreak to be attributed with certainty, as it is premature to pronounce with assurance without the judicial and administrative investigations currently underway having concluded.
Despite the coherence of the contaminated food hypothesis, scientists warn that the geographical origin of the virus cannot yet be determined with certainty. Currently, both the Spanish investigation, of which this report is a part, and the police inquiries by the Mossos d'Esquadra and the Guardia Civil remain open, under judicial secrecy in the court of Cerdanyola del Vallès.
