Swine flu strain with human pandemic potential increasingly found in Chinese pigs
What the world doesn’t need now is a pandemic on top of a pandemic. So a new finding that Chinese pigs are more and more frequently becoming infected with a strain of influenza that has the potential to jump to humans has infectious disease researchers worldwide taking serious notice. Robert Webster, an influenza investigator who recently retired from St. Jude Children’s Research Hospital, says it’s a “guessing game” as to whether this strain will mutate to readily transmit between humans, which it has not done yet. “We just do not know a pandemic is going to occur until the damn thing occurs,” Webster says, noting that China has the largest pig population in the world. “Will this one do it? God knows.”
When multiple strains of influenza viruses infect the same pig, they can easily swap genes, a process known as “reassortment.” The new study, published today in the Proceedings of the National Academy of Sciences, focuses on an influenza virus dubbed G4. The virus is a unique blend of three lineages: one similar to strains found in European and Asian birds, the H1N1 strain that caused the 2009 pandemic, and a North American H1N1 that has genes from avian, human, and pig influenza viruses.
The G4 variant is especially concerning because its core is an avian influenza virus—to which humans have no immunity—with bits of mammalian strains mixed in. “From the data presented, it appears that this is a swine influenza virus that is poised to emerge in humans,” says Edward Holmes, an evolutionary biologist at the University of Sydney who studies pathogens. “Clearly this situation needs to be monitored very closely.”
As part of a project to identify potential pandemic influenza strains, a team led by Liu Jinhua from the China Agricultural University (CAU) analyzed nearly 30,000 nasal swabs taken from pigs at slaughterhouses in 10 Chinese provinces, and another 1000 swabs from pigs with respiratory symptoms seen at their school’s veterinary teaching hospital. The swabs, collected between 2011 and 2018, yielded 179 swine influenza viruses, the vast majority of which were G4 or one of five other G strains from the Eurasian avianlike lineage. “G4 virus has shown a sharp increase since 2016, and is the predominant genotype in circulation in pigs detected across at least 10 provinces,” they write.
Sun Honglei, the paper’s first author, says G4’s inclusion of genes from the 2009 H1N1 pandemic “may promote the virus adaptation” that leads to human-to-human transmission. Therefore, “It’s necessary to strengthen the surveillance” of Chinese pigs for influenza viruses, says Sun, also at CAU.
Influenza viruses frequently jump from pigs to humans, but most do not then transmit between humans. Two cases of G4 infections of humans have been documented and both were dead-end infections that did not transmit to other people. “The likelihood that this particular variant is going to cause a pandemic is low,” says Martha Nelson, an evolutionary biologist at the U.S. National Institutes of Health’s Fogarty International Center who studies pig influenza viruses in the United States and their spread to humans. But Nelson notes that no one knew about the pandemic H1N1 strain, which jumped from pigs to people, until the first human cases surfaced in 2009. “Influenza can surprise us,” Nelson says. “And there’s a risk that we neglect influenza and other threats at this time” of COVID-19.
The new study offers but a tiny glimpse into swine influenza strains in China, which has 500 million pigs. While Nelson thinks the predominance of G4 in their analysis is an interesting finding, she says it’s hard to know whether its spread is a growing problem, given the relatively small sample size. “You’re really not getting a good snapshot of what is dominant in pigs in China,” she adds, stressing the need for more sampling in Chinese pigs.
In the paper, Sun and colleagues—including George Gao, head of the Chinese Center for Disease Control and Prevention—describe lab dish studies that show how G4s have become adept at infecting and copying themselves in human airway epithelial cells. The viruses also readily infected and transmitted between ferrets, a popular animal model used to study human influenza. The researchers found antibodies to the G4 strain in 4.4% of 230 people studied in a household survey—and the rate more than doubled in swine workers.
In addition to stepping up surveillance, Sun says it makes sense to develop a vaccine against G4 for both pigs and humans. Webster says at the very least, the seed stock to make a human vaccine—variants of a strain that grow rapidly in the eggs used to make a flu vaccine—should be produced now. “Making the seed stock is not a big deal, and we should have it ready,” Webster says.
China rarely uses influenza vaccines in swine. Nelson says U.S. farms commonly do, but the vaccine has little effect because it’s often outdated and doesn’t match circulating strains.
Ideally, Nelson says, we would produce a human G4 vaccine and have it in the stockpile, but that’s an involved process that requires substantial funding. “We need to be vigilant about other infectious disease threats even as COVID is going on because viruses have no interest in whether we’re already having another pandemic,” Nelson says.
Guys but I reckon we shouldn't be using God name here for he created us .He gave us brains to think .We humans make our decision to eat or do what we want to that includes stealing , cheating etc and HOPEFULLY not feel guilty about it. In which ever way our beliefs are ,we humans should respect it.
China dawg has to be brought to international courts and be judged, china cannot fight U.S, use dirty tactic.....cause pandemic....now starting on 2nd pandemic!
Yes exactly, what is a super power country? Certain part of China still consume dogs and cats. This should be stop. China don't compare to those vietnam, africa by saying many countries still doing that! Malu oh!
So are parts of South Korea (even in Seoul), Vietnam and Indonesia. And I believe some other parts of the world too. But people only complain about China only?
QueenElizebeth IV! So you're comparing China to Vietnam and Indonesia..Come on China is way ahead of those countries so they shouldn't be eating cats or dogs anymore haha.. You wanna be a super power country make sure you're acting right cause all your moves are being watched
For what? For discovery of new virus strain that has pandemic potential? You are talking like Trump? What crime? Stealing US IP, swine flu is actually US product, i think you maybe right, sue them.
Woi I am not pro Dog eaters or what. But lets put all those things aside la, every culture has its own food. For the vegans even eating Chickien is bad. Durian sounds like poison to Mat Salleh, Blue Cheese sounds like shit for Asian. How do you even judge?
traderstrades , going by your logic, Malaysia should have been brought to international court for Nipah virus? Saudi Arabia for Mers-Cov? Hong Kong for SARS? Continent of Africa for Ebola?
QueenElizebeth IV , the difference is that all of those together have not killed as much as Covid19 has killed in Just couple of months and is still killing. None of the viruses you named has shut the world economy like COVID19 has. I mean common just think before you write a comment.
I don’t know where did pig come into to this matter but anyway no, not for eating pig but to find out why are deadly viruses rising from China which cost the whole world so much of lives, money and happiness. I believe people of the world deserve to that.
Kenny Chua , how about pork? Can human consume pigs? What is the standard use to say dog and cat are humans' friend and pig is food? Amarican standard or vietnamese standard or chinese standard? I m very confused, but you sound few levels up from ppls agreed to eat dog and cat? Why like that? Racism against animals? Dog and cat lives matter? Pig live not matter? Very confusing.
Come on la China, You can't fight trade war against U.S,use dirty tactics a.k.a pandemic to cover yourself by making Global lockdown, scaremonger in Economic Market! Shame
MoneyMachineMaker发发发 just because you had the flu first and declare in your village, does it mean the flu started with you? Are you being naive by judging just because the declare a potential disease?
MoneyMachineMaker发发发 have you been to China? I mean all of China? It is just like me criticizing India as unhygienic, barbaric or other negative remarks when one does not know the culture or see the country. You are assuming a lot of things in your mind based on what you hear ...
Even many said China is the future? super power country? From what?.....stealing? lying? cheating? copying? pirating? So why so many china student goes to REAL super power country studying but not in own country china? If china so powderful, china students please stay in your own country and study in Hokkien(Fooking) University! I am a chinese and my grandfather comes from Guangdong, i feel ashamed on what China is doing recently! China nowadays are poor until got money only, no moral,dignity,fairness at all!
Stop importing frozen pork from Canada. Most probably contaminated with swine flu. Canada is still a colony of the US Imperialist. They can't decide independently, everything hv to be decided by US. A handicapped colony.
QueenElizebeth IV ! Not in a fat chance, china became strong because of colonizing.....Its actually exports! For Cheap, fake, pirated, copycat,black hearted polluted rubbish! And china male go overseas to became scammers, illegal gambling port, females goes overseas became kok kok kai prostitute! Correct me if i am wrong....
By the way QueenElizebeth IV, So where did China people got so much money from, to colonizing other countries? Got any good answer? I been living in China for quite sometime,know lots of dirty secrets from china, hopefully you can enlighten me...
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Posted by FancyMe > 2020-06-29 12:46 | Report Abuse
Thanks guys!