Scientists in China have found a new type of swine flu called G4 and are thought to be capable of causing a pandemic.

According to a study published June 29 in the journal PNAS, the main journal of the US National Academy of Sciences, G4 is derived from the H1N1 strain that caused the 2009 influenza pandemic.

"It possesses all the signs necessary to adapt highly to infect humans," the authors, including scientists from Chinese universities and the Centers for Disease Control and Prevention.

From 2011 to 2018, researchers collected 30,000 samples from pigs in slaughterhouses in 10 Chinese provinces and in a veterinary hospital, allowing them to isolate 179 swine flu viruses.

The researchers then conducted various experiments, including on ferrets (Ferret ferrets), which are commonly used in flu studies because they experience similar symptoms in humans.

G4 is considered to be highly contagious and causes more severe symptoms on ferrets than other viruses.

Scientists say the virus has been transmitted from animals to humans, but there is no sign that it can be transmitted from person to person and this is their concern.

"The concern is that the transmission of G4 viruses in humans will help them to increase adaptability in humans and increase the risk of pandemic disease to humans," the researchers wrote.

The study authors called for urgent measures to supervise people who work and contact pigs.

"The study is given as a strong reminder that we are constantly at risk of developing new pathogens and cattle, which are more exposed by humans than wildlife, may play a role.

The Chinese agriculture industry, where poultry and pigs are often kept close to each other, has long been considered a major cause of new strains of influenza virus.