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.

Source: Scmp.com

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.

Source: USA TODAY

14 sick, 5 dead as new bird flu moves beyond birds, threatens people

Staff from Taiwan's Center for Disease Control at Sungshan Airport in Taipei. Taiwan has raised its level of alert as new deaths from H7N9 bird flu have been reported. (Sam Yeh / AFP/Getty Images)

Staff from Taiwan’s Center for Disease Control at Sungshan Airport in Taipei. Taiwan has raised its level of alert as new deaths from H7N9 bird flu have been reported. (Sam Yeh / AFP/Getty Images)

The number of people sickened by the H7N9 bird flu virus climbed to 14 on Thursday — and the death count jumped to five — as the Chinese Ministry of Agriculture reported that it may have detected the virus in pigeon samples at a Shanghai poultry market.

Officials in Shanghai began slaughtering birds at the market to slow spread of the disease, which so far has infected only people who come in close contact with birds and does not appear to pass from person to person.

That a place like Shanghai appears to be a center for the spread of H7N9, which wasn’t known to sicken people before this outbreak, makes sense, said Trevon Fuller, a research fellow at UCLA’s Center for Tropical Research. Fuller and colleagues recently published a study (see related items at left for Los Angeles Times coverage) identifying potential hot spots for another bird flu strain that has killed people: H5N1.

They identified Shanghai among the key locations. The reason? Its high concentration of poultry production.

“It seems that whenever there’s this spillover of bird flu to humans, it’s associated with high numbers of poultry and intensive poultry production,” Fuller said.

The more birds present that catch different strains of a virus, the more opportunities exist for those strains to combine and reassort — creating new varieties like the novel H7N9 that could pose increased dangers to birds, animals and people.

Scientists will continue studying the outbreak to determine exactly how the virus gained the ability to sicken people, and how it spreads. According to the World Health Organization, lab experiments suggest that H7N9 does respond to antiviral medications like oseltamivir, but the drugs have not yet been used to treat any of the outbreak patients.

Reuters reported that Japan and Hong Kong had begun taking precautions, including monitoring airports and farms to combat the virus — although those efforts were called preliminary. Taiwan also has raised its level of alert, and Vietnam has banned poultry imports from China.

The World Health Organization is providing regular updates on H7N9 bird flu.

source : latimes.com

New bird flu strain creates fear and surveillance

French doctor Alix Greder-Belan shows a protective face mask to be used by hospital staff in case of a bird flu pandemic at the Mignot Hospital in Versailles October 10, 2005. REUTERS/Franck Prevel

French doctor Alix Greder-Belan shows a protective face mask to be used by hospital staff in case of a bird flu pandemic at the Mignot Hospital in Versailles October 10, 2005. REUTERS/Franck Prevel

An emerging bird flu that is mysterious and deadly is haunting China. With four fresh H7N9 cases reported in Jiangsu Province and no indication as to how three Chinese adults caught the little-noted avian flu virus that killed two of them in March, the global medical community is hoping the new flu will calm down until China’s health system can determine how it spread.

“I can tell you this thing is real and definitely has the markings of being a killer,” says Jason Tetro, coordinator of the Emerging Pathogens Research Centre in Ottawa, which on Monday examined gene sequences from three of China’s H7N9 cases.

“I don’t wish to cause panic,” Tetro said in an interview, noting that if the subtype were proven to have emerged from a small farm, he wouldn’t be much alarmed. Infecting a big poultry reservoir, on the other hand, might well enable H7N9 to access Asia’s wild bird population. The upstart subtype could then become as menacing as H5N1, which since 2005 has officially taken 371 lives in 622 cases, mostly in China, Southeast Asia and Egypt, according to the World Health Organization. The additional Chinese cases have convinced Tetro that “close contact with birds” has been involved. “And I think the CAFOs [industrial chicken farms] have definitely contributed to the evolution of this virus,” he says.

Already, “the internal genes of H7N9 are very close to those of H5N1,” says Mike Coston, a widely read American flu blogger, in an interview. (Coston’s Avian Flu Diary noted on March 14 that a paper in the U.S. Centers for Disease Control’s Emerging Infectious Disease Journal had identified the Shanghai area as one well suited to breed a new genetic subtype of influenza.)
In a development unwelcome to Chinese authorities, many Chinese microbloggers are associating the H7N9 deaths with the still-unexplained swine carcasses that last month floated down the Huangpu River, which provides Shanghai’s drinking water. (Local health officials announced on Monday that the dead pigs contained no bird flu virus.)

Memories of China’s repression of news during its tumultuous 2002-03 SARS outbreak could fuel panic and unrest at home and suspicion in the West. A Tuesday editorial in China Daily reminded readers that China’s minister of health and the mayor of Beijing were dismissed 10 years ago “for trying to cover up the disease.” And there are signs that authorities this time, too, have been less than forthcoming; the Jiangsu Province Health Department announced the four new H7N9 cases only after a microblogger whose Weibo profile says he is a hospital administrator posted a shot of what looked like a patient’s diagnosis on Tuesday.

This might explain why FluTrackers, a U.S. website that hosts a global volunteer disease-surveillance network, has been suffering renewed denial-of-service attacks that it says are originating in China. The Florida-based site first noted server overloads in April 2011 and was told by its server provider in mid-December 2012 that page views from China were running at an “astonishing” level that closed the month at almost 10 million, said Sharon Sanders, FluTrackers’ president and editor-in-chief, in a series of e-mail exchanges.

After FluTrackers banned Chinese IP addresses that were sending thousands of requests, traffic slowed by more than two-thirds, only to rebound in March to almost 6.7 million page views from China. “When the site goes down, it is extremely inconvenient,” wrote Sanders, but a backup site that uses “multiple social media venues” makes it “really impossible to take us down.”

Why would Chinese authorities care about FluTrackers? For one thing, the nonprofit website is watching China. An item Sanders posted on March 7 seems to have constituted the first overseas mention of the Shanghai H7N9 cases. While journalists in China and Hong Kong dig for stories there, FluTrackers has about 50 regular posters and several hundred intermittent volunteers tracking and documenting threats to public health — particularly emerging diseases — around the world. The site, which Sanders founded with some fellow H5N1 watchers in 2006, publishes daily in English, French, Dutch and Italian, biweekly in Spanish, and occasionally in German, operating 24 hours a day, seven days a week. “No one is paid. Everyone is a volunteer,” she wrote. “We do not accept any advertisements and we do not sell anything.”

On Monday, for instance, Chinese authorities and the World Health Organization took heart that no signs of human-to-human H7N9 transmission had surfaced. That evening, FluTrackers posted a machine-translation of a bylined report that had just been posted at wenweipo.com, a Hong Kong newspaper’s website. The story tells of unusual pneumonia cases afflicting four men and a woman in a Shanghai hospital — all aged 60 to 70 and with no history of interpersonal contact. Speaking anonymously, a doctor is quoted as saying the hospital annually copes with about three cases of “unexplained severe pneumonia,” but that all five of the special cases are being labeled as such, though they have not been isolated. A second report indicated that three of them may have died.

So does H7N9 have pandemic potential? “I’d say that the majority of virus comes from H9N2, which many researchers have suspected could be the next pandemic. The makeup of this virus is similar to one that researchers have suspected could be the next pandemic. However it’s not quite there yet,” says Tetro. “We know that it is not spreading from human to human, but we know that in some cases, direct or close contact with poultry or birds is a route of infection.”

On the other hand, he finds the revelation of fresh cases in Jiangsu comforting: “This is actually an official statement. I’m more optimistic that we’re going to have a better epidemiological understanding of what is happening in China.”

“Many epidemics break out, spread and burn themselves out all the time in China. We just never hear about them,” says Coston. “But I think it’s already in the birds.”
We’ll all be watching.

source : blogs.reuters.com

Unknown strain of bird flu kills two people in China

Quick action has led to tens of millions of birds have been culled to stop the spread, which has been brought under control by animal vaccination programs.

Quick action has led to tens of millions of birds have been culled to stop the spread, which has been brought under control by animal vaccination programs.

A frightening new form of bird flu, heretofore undiagnosed and unidentified has killed two men in China. It doesn’t discriminate in age, as the two victims were aged 27 and 87. Both men fell ill in Shanghai, one of the country’s largest cities, in late February and died earlier this month.

LOS ANGELES, CA – Another woman in nearby Anhui province has contracted the virus and is listed in a critical condition.

According the Chinese National Health and Family Planning Commission, the strain of the bird flu virus found in all three people was identified as H7N9, which had not been transmitted to humans before.

The first birds were infected in 1996. Bird flu was then transmitted to human beings in Hong Kong the following year.

Experts warn that the highly contagious disease is the world’s biggest pandemic threat and could kill between five million and 150 million people. The disease is expected to mutate within birds. Doctors have been able to head off the infection in Asia due to vaccination programs.

Seventeen governments around the world are preparing vaccines to combat a pandemic. Symptoms of the new strain include fever and coughing that later develops into pneumonia. It’s not yet known how the three people became infected.

The World Health Organization says it is “closely monitoring the situation” in China, regional agency spokesman Timothy O’Leary said in Manila, Philippines. The WHO says that the latest strain isn’t contagious.

“There is apparently no evidence of human-to-human transmission, and transmission of the virus appears to be inefficient, therefore the risk to public health would appear to be low,” O’Leary said.

While WHO is confident the latest strain will not easily spread – no symptoms have been reported in any people who had been in contact with the victims, the deaths are sure to reignite fears over the disease.

The most common strain of bird flu, H5N1, found mainly in Southeast Asia, is highly contagious among birds and can spread to humans.

Quick action has led to tens of millions of birds have been culled to stop the spread, which has been brought under control by animal vaccination programs.

The WHO says there have been 566 confirmed human cases of H5N1 since 2003 and 322 deaths. Governments around the world are pumping millions of pounds into developing vaccines in the scenario of a pandemic. ( catholic.org )

Combination of bird, human flu can be dangerous, warns study

Researchers at the University of California, Los Angeles (UCLA), have confirmed that genes from bird flu and human flu combined together can create dangerous new flu strains, mainly in the bird flu prevalent countries including Bangladesh.

The flu season this year is expected to be lengthier and the disease could be pandemic if bird flu becomes highly contagious among humans, researchers predicted in a study, published on Friday.

In Bangladesh, so far eight people had died of bird flue until 2010. However, some 800 people were infected and later cured until 2012, according to the Ministry of Health.

The respiratory virus, which infects pigs and humans only sporadically, spreads mainly through coughs and sneezes.

Flu season occurs during the end of winter and rages for several months among birds, humans and animals. Often the viruses become deadly.

In 2009, H1N1 swine flu outbreak killed 280,000 people worldwide when viruses from humans and animals exchanged genes to create a new virus in a process called ‘reassortment’, the study revealed.

Earlier, the flu killed more than a million people each time when it broke out in 1957 and 1968, the study said.

The researchers have advised the relevant authorities in the bird flue prevalent countries to vaccinate people, poultry and livestock and monitor animals for evolution of new viruses, which could help predict and prevent a probable pandemic disease.

According to the World Health organisation (WHO), China, Egypt, India, Vietnam, Indonesia and Bangladesh have been the hosts to ongoing, widespread of bird flu infections in poultry since 2011.

A research study of the UCLA revealed that the researchers had to work with limited data as they had lacked adequate data for bird and human flu outbreaks in all these six bird flu host countries.

The research study was published by Texas-based Red Orbit Science, Space, Technology, Health News and Information on Friday.

The study said the scientists had to identify indicators of flu outbreaks, such as dense poultry populations, or rain and temperatures that encourage flu transmission.

“For each type of flu, we identified variables that were predictive of the various virus strains,” the study report quoted UCLA postdoctoral research fellow Trevon Fuller as saying.

“We wanted a map of predictions continuously across the whole country, including locations where we didn’t have data on flu outbreaks,” Fuller said.

Using surveillance of influenza cases in humans and birds, the researchers have come up with a technique to predict sites where these viruses could mix and generate a future pandemic, the study said.

The researchers’ models revealed that coastal and central China and Egypt’s Nile Delta are danger zones where bird flu could combine with human flu to create a virulent kind of ‘super-flu’.

Governments can prioritise these zones – and use the researchers’ models to identify other hotspots – for increased monitoring of flu in humans, livestock, poultry and wild birds.

“That could help detect a novel flu virus before it spreads worldwide,” the study said.

Researchers using mice confirms that genes from bird flu and human flu can combine to create dangerous new flu strains.

Swine, which is susceptible to both bird and human flu, could serve as a mixing vessel for ‘reassortment’ between the two viruses.

“The mixing of genetic material between the seasonal human flu virus and bird flu can create novel virus strains that are more lethal than either of the original viruses,” the study quoted another UCLA researcher Thomas Smith.

The research focused on two flu strains that, as studies in mice have shown, can combine with lethal results, that is the seasonal H3N2 human flu, and the H5N1 strain of bird flu that has occasionally crossed over into humans.

Currently, H5N1 has a 60 per cent mortality rate in humans but is not known to spread between humans frequently.

Bird flu has taken a big toll in Bangladesh since its fresh outbreak in 2007. The number of farms has come down to 70,000 from 150,000 over the last five years, according to the Bangladesh Poultry Industries’ Association.

sources: thefinancialexpress-bd.com