The Catalan Ministry of Health assessed the risk to the general population as “very low.” The infected individual showed no flu-like respiratory symptoms, and tests of people who had contact with the patient confirmed that the virus had not spread.

An earlier report from El Pais, citing ministry sources, stated that the patient—now recovered—had no contact with pigs or pig farms, leading experts to conclude that the virus likely transmitted from human to human.

Authorities are on alert because of the virus’s potential to cause a pandemic if it recombines with a human flu virus. Such a scenario could occur if a pig were simultaneously infected with both viruses.

The WHO did not immediately respond to Reuters’ request for comment.

In 2023, the Netherlands reported a confirmed human infection with the A(H1N1)v swine flu virus in an adult with no history of occupational exposure to animals.

The 2009 swine flu pandemic infected millions of people worldwide. It was caused by a virus containing genetic material from viruses circulating in pigs, birds, and humans.