This is a worrying study American scientific magazine PNAS has released: in China, employees in a slaughterhouse have been contaminated by a swine flu from the H1N1 flu strain. Facts are not new, the article released in the American magazine shows the results of a long research carried out between 2011 and 2018. According to researchers, these new G4 viruses bear all of the “essential hallmarks of being highly adapted to infect humans.”
Should we be afraid of a new pandemic? If for now scientists have recorded no human to human transmission, the threat is real and must be monitored. “The work comes as a salutary reminder that we are constantly at risk of new emergence of zoonotic pathogens and that farmed animals – with which humans have greater contact than with wildlife – may act as the source for important pandemic viruses” head of the department of veterinary medicine at Cambridge University James Wood commented.
The study that worries us today, has been led between 2011 and 2018, 30,00 nasal swabs have been performed on pigs in slaughterhouses in ten Chinese provinces and a veterinary hospital. Searchers have isolated 179 swine flu viruses, most of them being the new strain, that has been dominant in pigs since 2016. Then, scientists have carried out different experiments in laboratory on ferrets, animals widely used in researches on the flu because their symptoms can be compared to humans’: they have fever, sneeze, and cough.
They have noticed that G4 viruses are the most infectious. The latter replicate within the human cells and cause in ferrets more severe symptoms than other strains. Moreover, in vitro tests show immunity after being in contact with the human seasonal flue viruses does not protect against the G4 virus.
The study also shows that many workers and people working with pigs have been infected: 10.4% according to blood tests looking for antibodies against the virus. We also note that 4.4% of the overall population seems to have been infected. The virus has already been passed on to humans, but there is no proof they can pass it on to human.
The transmission risk is currently under close monitoring: “It is of concern that human infection of G4 virus will further human adaptation and increase the risk of a human pandemic” the scientists wrote. They think it is urgent to monitor people working with pigs.