A new strain of swine flu virus (G4) has been found in 10% of workers working with pigs and in 4% of the general population in China, researchers in a recent study find. For the moment, no human-to-human transmission has been observed.
[Mise à jour le lundi 6 juillet à 10h39] Researchers in China detect a new family of swine flu virus, reveals a study* published Monday June 29, 2020 in the American scientific journal Proceedings of the National Academy of Sciences. To achieve this identification, the authors of Chinese Universities and the Center for Prevention and Control of Chinese Diseases carried out, between 2011 and 2018, more than 30,000 nasal swabs on pigs in slaughterhouses in 10 Chinese provinces as well as in a veterinary hospital. These analyzes made it possible toisolate 179 virus swine flu, the majority of which has been present in pigs since 2016. One of these viruses, called G4 EA H1N1, was found at 10.4% of workers in the pork industry, especially those between the ages of 18 and 35. And according to blood tests capable of looking for the presence of antibodies to this virus, 4.4% of the general Chinese population also appears to be contaminated. This virus is therefore present in humans, even if at the moment, no human-to-human transmission was observed. However, pigs are considered to be important hosts for the transmission of swine flu viruses. Researchers, fearing the arrival of a new pandemic, recommend urgently setting up increased surveillance of populations working in the pig sector.
Pigs are considered to be important hosts for the transmission of swine flu viruses.
This new swine flu virus (G4 EA H1N1) genetically descended from the H1N1 strain, responsible for pandemic a 2009, a “has all the essential traits showing high adaptability to infect humans “, explain the study authors. In other words, this new strain of swine flu virus has all the characteristics that could lead to a future pandemic. “This work is a salutary reminder that we are constantly at risk of the emergence of zoonotic pathogens, and that farm animals, with which humans are more in contact that with wild animals, be the source of important pandemic viruses“comments James Wood, head of the Department of Veterinary Medicine at the University of Cambridge.
To determine the risks of infection in humans, the researchers carried out several laboratory experiments on ferrets, animals commonly used in influenza research because their symptoms are similar to those of humans. Ferrets are able, like humans, to cough, sneeze and have a fever. The researchers found that:
→ The G4 EA H1N1 virus was more infectious than other H1N1 strains
→ The G4 EA H1N1 virus was able to replicate in human cells
→ The G4 EA H1N1 virus was capable of causing more severe symptoms than other H1N1 strains
→ The immunity obtained after contact with a human seasonal influenza virus does not provide protection against the G4 EA H1N1 virus.
Swine flu is a strain of the flu virus that usually affects pigs, but which can also affect humans. Symptoms of swine flu are close to those of seasonal flu :
- Fever
- Cough
- Throat irritation
- Chills
- Muscle aches or aches
- Sometimes diarrhea and vomiting
According to the researchers, it is possible that the G4 EA H1N1 virus causes more serious symptoms than the seasonal flu virus.
* “Prevalent Eurasian avian-like H1N1 swine influenza virus with 2009 pandemic viral genes facilitating human infection”, PNAS, Honglei Sun, Yihong Xia, 29 juin 2020.
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