Chaos in China as swine flu variant sparks epidemic fears after 'alarming' rise

The spread of a swine flu variant is raising concerns that the virus could develop to the point where it can be passed between humans. A study led by a group of scientists in China found that if the Influenza D virus (IDV) continues to evolve in animals, it could make the leap to people.

Experts led by Hongbo Bao from Changchun Veterinary Research Institute have studied the D/HY11 strain of IDV, which appeared among cattle in northeast China in 2023. Lab tests found the strain was capable of reproducing in the cells which line a person's airways and in animal tissue. The study also found the strain could "efficiently transmit" through the air between live ferrets.

Observations carried out between 2020 and 2024 in China's north east revealed "alarming" rates of exposure to the strain. The report found 73.7% (449 out of 612 cases) in the general population studied were exposed to D/HY11 and 96.67% (58 out of 60) among people with respiratory symptoms, such as coughing, sore throat and runny nose.

The "extraordinarily" high positive test results for the strain in north east China highlight a possible "silent spread" in mammals with mild symptoms, according to the study.

When scientists tested common flu drugs in the lab, only one type, polymerase inhibitors, was able to stop IDV from making copies of itself.

However, D/HY11 was better at copying itself than the original strain of the virus, with initial research suggesting this might be due to a specific gene in the virus called the P3 gene. Experts suggest this could be helping it work more efficiently.

The Chinese scientists' findings indicate IDV "may" have developed the capacity for transmission between humans as it has evolved. They argue current strains of IDV could pose a "potential" threat to larger regions or even to the rest of the world.

At the end of the report, the authors of the study say D/HY11 may pose a risk of passing from animals to humans and that the strain could develop the potential to trigger an epidemic.

In Britain, the first human case of swine flu was detected in North Yorkshire in 2023 as part of routine surveillance by the UK Health Security Agency and the Royal College of General Practitioners.

The case of influenza A(H1N2)v led to a "mild" illness in the individual who fully recovered, according to UKHSA.