Scientists discover new bird flu virus ‘worse than H7N9’

Professor Guan Yi. Photo: Nora Tam

Professor Guan Yi. Photo: Nora Tam

Hong Kong scientists studying the H7N9 bird flu virus said they had discovered another H7-type virus lurking in chickens in China.

Dubbed H7N7, the virus was able to infect mammals in a lab experiment, said the team, warning H7 viruses “may pose threats beyond the current outbreak”.

“The continuing prevalence of H7 viruses in poultry could lead to the generation of highly pathogenic variants and further sporadic human infections,” they wrote in the journal Nature .

“If (we) let this H7N7 continue circulating in chickens, I am sure that human infection cases will occur,” study co-author Guan Yi from the University of Hong Kong said.

“This virus could cause more severe infection than … H7N9, based on our animal experiment,” he said.

H7N7 spreads easily in birds. It caused one human death and more than 80 cases of mild disease in the Netherlands in 2003.

For the new study, researchers led by Maria Huachen Zhu and Guan took the H7N7 virus they had found in poultry and tested it on ferrets in the lab. The animals, considered a good human model, developed severe pneumonia, suggesting the virus is potentially also infectious for us.

“We think it is scary for humans,” said Guan. “Our entire human population almost has no antibodies against the H7 subtype of influenza virus. Thus, if it causes pandemic outbreak, it will kill many people.”

Among a sample of 150 chickens tested, 36 carried the H7N7 virus, said Guan. Many birds had both H7N7 and H7N9.

Strains of the H5, H7 and H9 avian influenza subtypes have caused human infections, mainly following direct contact with infected poultry. None of the strains have mutated to become easily transmissible from person to person – the epidemiologist’s nightmare.

The best-known strain is the H5N1 virus that has caused 633 confirmed flu cases in humans in 15 countries from 2003 to July this year, of whom 377 died – a death rate of about 60 per cent.

Guan and a team used genetics to determine that H7 precursor viruses were first introduced to southeast China by migratory birds to domestic ducks, where they circulated from 2010 and were then transferred to chickens.

The viruses then mixed with endemic chicken viruses to create the H7N9 and H7N7 variants, which could spread to humans at live poultry markets.

“We need to take samples from different types of poultry regularly to see what kinds of viruses are circulating in these birds,” Guan said.


Evidence suggests new bird flu spread among people

A vendor holds a chicken at a chicken whole sale market in Shanghai, China.(Photo: AP Photo)

A vendor holds a chicken at a chicken whole sale market in Shanghai, China.(Photo: AP Photo)

LONDON — Chinese scientists have found the strongest evidence yet that a new bird flu strain is sometimes able to spread from person to person, but they are emphasizing that the virus still does not transmit easily.

The new bird flu strain, known as H7N9, was first reported by Chinese authorities in March. As of the end of May, there were 132 cases and 37 deaths in China and Taiwan linked to the virus.

Health officials suspect patients were most likely infected by birds in live animal markets but acknowledged there were probably sporadic cases of the virus spreading among humans. Except for a single case reported last month, the infections appear to have stopped since Chinese authorities took measures to slow the virus, including shutting down live markets across the country.

In the new study, Chinese researchers interviewed the family and close friends of a father and daughter both killed by H7N9 in eastern China to figure out how the virus might have spread between them. Both patients lived in the same household, were critically ill during the investigation and could not be interviewed.

The father, 60, was in charge of buying food for the family and bought six live quails before falling sick. His daughter, 32, rarely left the residential district where they lived and didn’t have any known contact with birds, except for two black swans raised by the property owners.

The daughter took care of her father when he became ill, without wearing any protective equipment. She fell sick several days afterward and died one month later. The bird flu viruses isolated from the father and daughter were nearly genetically identical.

There is no definitive test to prove when a virus has spread from human-to-human, but scientists consider matching viruses and eliminating other ways the virus might have spread to be convincing evidence. Scientists also tested 43 contacts of the two patients; none had H7N9.

“In this cluster, the virus was able to transmit from person-to-person,” wrote Xian Qi of the Jiangsu Province Center for Disease Control and Prevention, who was the lead author of the study. The scientists concluded the transmission was “limited and non-sustainable.” The paper was published online Tuesday in the journal BMJ.

“It is also notable that the transmission occurred between blood relatives,” said Dr. Peter Horby, a bird flu expert at Oxford University Clinical Research Unit in Hanoi, Vietnam, in a statement. Horby, who was not involved in the latest study, noted there is some evidence that genetic factors may make some people more susceptible to bird flu.

In an accompanying commentary in the BMJ, experts said similar patterns had been seen with other types of bird flu, including H5N1, another feared bird flu strain that first emerged in 1996 and has since killed millions of chickens. It has sickened more than 600 people and caused 377 deaths, mostly in Asia.

“To observe some transmission of H7N9 from human-to-human…does not necessarily indicate the virus is on course” to spark a pandemic, wrote James Rudge of the London School of Hygiene and Tropical Medicine, who is based at Mahidol University in Thailand, and Richard Coker of the National University of Singapore.

Still, Rudge and Coker noted several worrying features about H7N9, such as its ability go undetected in birds before sickening humans. They also warned officials to be on guard for a possible return of H7N9 in the winter; flu viruses typically spread more easily in cold weather.

“The threat posed by H7N9 has by no means passed,” they said.


Studying Animals To Improve Human Health

20130626-Duck-genome-editorialThe recent outbreak of H7N9 avian influenza in China marks the first time that this subtype has crossed the species barrier to infect humans. After some genetic detective work, Chinese scientists came to the worrying conclusion that the outbreak strain is actually a mishmash of genes from four different bird influenza viruses: one from ducks, another from migratory birds, and two from chickens.

Birds provide ideal conditions for gene exchange among influenza strains – many bird species are naturally infected with a diversity of influenza viruses, but show only mild disease symptoms, or none at all. Scientists interested in understanding how birds and the virus coexist now have a valuable resource: the genome of the duck.

New tool in battle against influenza

An international team of scientists has just sequenced the duck genome, one of the most important reservoir species for influenza. The research, published in Nature Genetics and led by Professor Ning Li of the China Agricultural University in Beijing, also identified genes that are likely to play key roles in duck immunity against avian influenza.

Before they make us sick, many emerging and existing pathogens go through complex transmission cycles involving animal or insect species. Zoonoses, or diseases that cross species barriers into humans – avian influenza, SARS, and Nipah virus, for instance – will continue to pose health threats as we encroach onto animal habitats, farm huge numbers of livestock, and consume exotic meats (or, in the case of toxoplasmosis, snuggle with our pet cats). While the development of vaccines and drugs for use in humans obviously remains essential, research that focuses on non-human links in the chain of transmission also has potential to make a huge impact on human health.

“Studying host-pathogen interactions in ducks potentially might be used to design new anti-influenza drugs, especially anti-avian influenza drugs, develop modified birds that are genetically resistant to avian influenza infection, and suppress transmission of avian influenza,” said Prof. Li in an interview with Asian Scientist Magazine. “Such applications of host-pathogen interactions in ducks will improve our ability to cope with the possible pandemic threat of influenza virus in animals and humans.”

With the duck genome in hand, Prof. Li and his colleagues were able to determine which genes are activated in response to infection with avian influenza. Some of these are members of gene families that have expanded in ducks compared to chickens, turkeys, and zebra finches, suggesting that they may play unique roles in the duck’s defense mechanisms against the virus. The researchers are planning more studies to unravel the mechanisms by which these genes, as well as other candidates, protect the duck against influenza.

The study of insect vectors of disease is another example of research aimed at targeting non-human links in transmission chains. The dengue mosquito, for example, is notoriously difficult to eliminate by conventional methods such as insecticide spraying, and an effective vaccine or drug against dengue virus for use in humans has yet to be developed. The sequencing of the mosquito genome, however, was a huge boon to researchers studying how the mosquito immune system defends against dengue virus.

Such studies have already led to field trials of novel biological control strategies targeting the vector – the release of mosquitoes carrying bacteria that render the insects refractory to dengue infection, for example. Similar methods are being applied to mosquito species that transmit malaria, a disease which takes an enormous toll on global health.

The case for studying the obscure

While it is easy to make a case for studying ducks and mosquitoes, many pathogens infect us by way of species that are relatively obscure. Research on these seemingly less medically or economically important organisms is often viewed as a waste of taxpayer dollars. On an American talk show earlier this year, Stephen Moore, a prominent economist and editor at the Wall Street Journal, ridiculed publicly-funded research on snail mating habits.

Yet, this research was funded with good reason: snail-borne diseases affect an estimated 300 million people around the world today, mostly in disadvantaged communities in Asia and Africa. The parasites that cause schistosomiasis, for example, develop in freshwater snails into forms that are infectious to humans, before being released into river water.

And what about animals that do not harbor disease? Beyond agricultural or economic priorities (such as breeding meatier farm animals) studying animals and their genomes can also help us understand human disease and potentially develop treatments.

Take dogs, for instance: recent research suggests that the genomes of dogs and humans have evolved in parallel over millennia of intimate association, such that we have come to share common genetic mechanisms for many diseases: several types of cancer, obsessive-compulsive disorder, and epilepsy, to name a few. In fact, more than 360 human diseases with a genetic basis have also been described in dogs, often with very similar clinical manifestations and drug responses.

The line between human and veterinary medicine is beginning to blur; studies of canine disease have already led scientists to new insights into human biology. For example, the identification of a genetic mutation associated with narcolepsy in Doberman Pinschers has shed light on sleep regulation in humans, while the discovery of a novel disease mechanism underlying epilepsy in dachshunds may explain related disease in humans. So the next time your dog attempts to usurp some sofa space, move over; after all, you and he already share so much more than that.

Of course, the sequencing and analysis of an organism’s genome is neither a trivial nor a cheap undertaking, and scientists should be required to make an excellent case for the use of public funds to do so – sequencing an entire zoo of animals is probably not the answer to the world’s problems. But sometimes the most elegant solutions may be hidden inside the strangest creatures; excuse me while I turn my attention to the latest scientific Jungle Book story: how does the naked mole rat not get cancer?


Vendors keep selling pet birds despite ban

Bird lovers shop for pet birds Sunday at an unlicensed outdoor market near the intersection of Chengdu Road North and Dagu Road. Business at the market, held every Sunday, wasn't affected by the recent bird flu cases, which caused local authorities to suspend licensed bird markets in the city. Photo: Yang Hui/GT

Bird lovers shop for pet birds Sunday at an unlicensed outdoor market near the intersection of Chengdu Road North and Dagu Road. Business at the market, held every Sunday, wasn’t affected by the recent bird flu cases, which caused local authorities to suspend licensed bird markets in the city. Photo: Yang Hui/GT

Pet bird vendors posing as bird lovers continued to ply their trade on the streets Sunday despite the municipal government’s prohibition on the sale of poultry, pigeons and other birds in local markets after several cases of bird flu were discovered in the city.

The Shanghai Administration for Industry and Commerce ordered three poultry wholesale markets and 461 retailers to stop selling live poultry last Friday, according to the Shanghai municipal government’s microblog.

The administration also shut down 84 vendors who sold live poultry on the street, along with one unlicensed vendor, and prohibited the sale of birds at local flower and bird markets, the post said.

The new strain of bird flu, called H7N9, had killed four people and infected 10 in Shanghai as of Sunday afternoon.

The industry and commerce administration has not found any birds for sale at local flower and bird markets in Huangpu district, according to a staff member surnamed Gao.

“We started patrolling the flower and bird markets after the order came out Friday,” Gao told the Global Times.

Nonetheless, a dozen or so sidewalk vendors who sell pet birds every weekend in Yanzhong Green Space in Huangpu district have remained in business.

“I have kept birds for more than 30 years and I have kept this one for more than a year. Pigeons are likely to have bird flu because they come in contact with other wild birds, but these house-raised birds have always been kept in cages,” one vendor told the Global Times.

The vendor doesn’t see a problem with the birds as long as they are kept in a clean space and their owners wash up after handling them.

Zhang Ronghua, a security guard at the green space, said the problem with the unlicensed bird vendors wasn’t the possibility of spreading bird flu, but that they were taking up too much public space.

The city’s appearance authority said it will take measures to stop the trade if it finds sidewalk vendors selling birds.

The municipal government also temporarily banned all performances involving live birds in the city.

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China bird flu virus found in more markets in Shanghai

Shanghai: Chinese authorities have found traces of a new bird flu virus that has killed six people in more areas in Shanghai, state media reported, after authorities slaughtered over 20,000 birds at a large poultry market in the city. State-run Xinhua news agency said samples of the H7N9 virus were found at two markets selling agricultural products in the Minhang district of Shanghai, a city of 23 million people that is China’s financial hub.

The markets were near the Huhuai live poultry market where infected pigeons were discovered earlier in the week and where the culling was carried out. The new strain of bird flu has infected 16 people in China, all in the east of the country. Six people have died, and the outbreak has spread concern overseas and sparked a sell-off in airline shares in Europe and Hong Kong.

The strain does not appear to be transmitted from human to human, but authorities in mainland China and Hong Kong said they were taking extra precautions. Shanghai has banned all live poultry from other parts of the country from entering the city, and has now closed three markets to stem the spread of the virus, Xinhua said.

Six people have died so far and the outbreak has spread concern overseas and sparked a sell-off in airline shares in Europe and Hong Kong.

Six people have died so far and the outbreak has spread concern overseas and sparked a sell-off in airline shares in Europe and Hong Kong.

Hong Kong’s government said it is intensifying surveillance of travelers and poultry coming into the city. China and Hong Kong were badly hit by the 2002-2003 epidemic of Severe Acute Respiratory Syndrome (SARS) that started in China and killed about one-tenth of the 8,000 it infected worldwide.

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How bad is the H7N9 bird flu? We give you the scary answers

An elderly woman eyes a cockerel suspiciously in Beijing.

An elderly woman eyes a cockerel suspiciously in Beijing.

A BIRD flu virus never found in humans grabbed headlines this week after it infected and killed people in China
Scientists have been scrambling to understand how it happened and, more importantly, whether it poses a risk to public health or could potentially spark a global pandemic.

The good news is that so far there’s no sign that the H7N9 virus is spreading from person to person, but experts say it has mutated in a way that has left them a bit worried. Here’s a crash course in Bird Flu 101 to help explain what’s known about the strain and why it matters:

Q: What is the H7N9 virus and what do we know about it?

A: The H7N9 strain – named for the combination of proteins on its surface – has infected at least 14 people in China since February, killing five of them, the official Xinhua News Agency said.

The latest cases were confirmed Thursday, four days after the initial announcement. Symptoms include fever and respiratory problems, including severe pneumonia. Much still remains unknown about the virus, including how people are getting infected, but scientists say it contains genetic markers that could help it infect humans. It is believed to be able to circulate in poultry stocks without sickening birds.

This can allow it to spread in flocks unnoticed, making it much harder to track and also possibly creating more contamination since the birds are surviving and spending more time on farms, in markets and elsewhere.

Q: How concerned should the public be about the H7N9 virus?

A: At this point, experts say there is no cause for alarm, but they are watching it closely.

No evidence exists that the virus is spreading from person to person, and no cases have been reported outside China. Samples are being collected from patients, and the Chinese Centre for Disease Control and Prevention is sharing genetic sequences with outside scientists.

This allows the world’s top flu experts to study the virus and look for mutations that could make it more dangerous. Poultry and its products are safe to eat as long as they are properly cooked.

Q: Is there a vaccine?

A: No vaccine exists, but the World Health Organisation and its partners are already working to isolate and identify possible candidate viruses that could be used to make a future vaccine if necessary. However, it would likely take months to produce the first doses.

Q: What changes are scientists seeing in the virus and why is this important?

A: Although it is not yet clear, the virus appears to have mutated in a way that would make it easier for it to adapt and grow at normal body temperature in mammals. Scientists are working to figure out which species could now be playing host to the virus, and one possibility is pigs.

Swine are important because they share some basic biological similarities with humans, and they can serve as “mixing vessels” if infected with different flu strains at the same time.

Other possibilities are that the mutations could be occurring in poultry or they are being generated after people are infected by birds.

“To me, the most important question to find out is: What is the actual host of this virus?” said Richard Webby, director of a WHO flu centre at St. Jude Children’s Research Hospital in Memphis, Tennessee. “It really looks like there’s been some mammalian host involved.”

Q: How is this bird flu different from the H5N1 strain everyone has been so concerned about in the past?

A: The H5N1 virus is highly lethal in birds, making it easier to identify and eliminate poultry outbreaks. H5N1 remains an avian influenza and has not taken root in another species, such as pigs.

Most human infections have been linked to contact with infected birds. Scientists have been closely watching the virus since it first appeared in Hong Kong in 1997.

It resurfaced in 2003 and decimated poultry stocks across Asia and has since killed at least 371 people. About 60 per cent of those infected die, and experts have long feared the H5N1 virus could mutate into a form that spreads easily from person to person, possibly igniting a pandemic.

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