Skip to main content
Part of complete coverage on

WHO: H7N9 virus 'one of the most lethal so far'

By Peter Shadbolt, CNN
updated 7:15 AM EDT, Fri April 26, 2013
STORY HIGHLIGHTS
  • NEW: First H7N9 bird flu case in Taiwan has been reported, health officials say
  • Death toll from China's bird flu outbreak 23, with 110 infections -- includes one in Taiwan
  • WHO's Keiji Fukuda warns H7N9 is one of 'the most lethal flu viruses we have seen so far'
  • Authorities struggling to understand virus which is mild in some cases but lethal in others

Hong Kong (CNN) -- On the same day yet another death was reported in China's bird flu outbreak, the World Health Organization warned the H7N9 virus was one of the most lethal that doctors and medical investigators had faced in recent years.

"This is an unusually dangerous virus for humans," Keiji Fukuda, WHO's assistant director-general for health, security and the environment told a news conference in Beijing Wednesday.

"We think this virus is more easily transmitted from poultry to humans than H5N1," he added, referring to the bird flu outbreak between 2004 and 2007 that claimed 332 lives.

READ: Researchers: Elderly more at H7N9 risk

Map: Bird flu spread  Map: Bird flu spread
Map: Bird flu spreadMap: Bird flu spread
Virologist: Bird flu 'cause for concern'
WHO: Bird flu outbreak especially lethal
Poultry markets closed over bird flu

"This is definitely one of the most lethal influenza viruses that we have seen so far."

As investigations continue into the possible sources of infection, Fukuda warned that authorities were still struggling to understand the virus. The WHO said China must brace for continued infections.

Fukuda's warning came as Taiwanese health authorities said they've confirmed the first human case of H7N9 in Taiwan -- one they said was imported from China.

A 53-year-old Taiwanese man who worked in eastern China was confirmed to have H7N9 on Wednesday, the Taiwanese Centers for Disease Control said. His condition was described to be severe.

He had been traveling back and forth regularly between China's Jingsu province and Taiwan, health officials said.

"According to the case, he had not been exposed to birds and poultry during his stay in Suzhou (in Jingsu province) and had not consumed undercooked poultry or eggs," the Taiwanese CDC said.

Taiwanese health officials said they are screening travelers arriving from China for signs of H7N9.

Fukuda, meanwhile, said WHO officials "are at the beginning of our understanding of this virus."

"(The situation remains) complex, difficult and it is evolving," he said.

So far there is no evidence of sustained human-to-human transmission, the authorities say.

"We do want to note, however, that if limited person-to-person transmission is demonstrated in the future, this really will not be surprising," Fukuda warned, adding that it was critical to remain vigilant, monitoring the virus's spread and mutation.

READ: Bird flu eats up Yum profits in China

"We are not sure that the clusters were caused by common exposure to a source of the virus or were due to limited person-to-person transmission," he said. "Moreover we have not seen sustained person-to-person transmission."

While some elements of the outbreak have baffled investigators -- specifically why the virus tends to target an elderly demographic and the fact that it is asymptomatic or mild in some cases and lethal in others -- authorities have claimed some significant victories in the fight against a pandemic.

Anne Kelso, the director of a WHO-collaborating research center, said researchers had seen a "dramatic slowdown" in human cases in Shanghai after the city's live poultry market was shut on April 6. Describing the finding as "very encouraging," she said evidence suggests the closure of live poultry markets is an effective way to stop the spread of the virus.

This is an unusually dangerous virus for humans
Keiji Fukuda

The joint inspection team from China's National Health and Family Planning Commission and the World Health Organization also found that, so far, no migratory birds have tested positive for the virus, taking another worrying route of transmission out of the equation.

It said the H7N9 virus is only being found in chickens, ducks and pigeons at live poultry markets.

WHO officials said there are already efforts underway in other countries to develop a vaccine after Chinese officials admitted international help would be needed with this.

Meanwhile, the National Health and Family Planning Commission said in its daily update on H7N9 cases that a total of 109 H7N9 cases have been reported within mainland China, including 23 deaths. Most cases have been confined to Shanghai and neighboring provinces in eastern China.

CNN's Ivan Watson and Feng Ke in Beijing contributed to this report.

ADVERTISEMENT
Part of complete coverage on
updated 1:18 AM EDT, Wed October 29, 2014
A top retired general has confessed to taking bribes, becoming the highest-profile figure in China's military to be caught up in President Xi Jinping's war on corruption.
updated 1:07 AM EDT, Mon October 27, 2014
A group in China escapes from a stuck elevator thanks to one man and his trusty hammer. CNN's Kristie Lu Stout reports.
updated 9:52 AM EDT, Thu October 23, 2014
Facebook's founder says he taught himself Mandarin and tested his skills with students in China.
updated 9:33 PM EDT, Thu October 23, 2014
China launched an experimental spacecraft that is scheduled to orbit the moon before returning to Earth.
updated 12:19 PM EDT, Tue October 28, 2014
Full marks for ingenuity: This was a truly high-tech scam.
updated 1:26 AM EDT, Tue October 21, 2014
The rationale behind Confucius Institutes -- an international chain of academic centers run by an arm of the Chinese government -- is understandable.
updated 11:11 AM EDT, Fri October 24, 2014
Smooth jazz saxophonist Kenny G wants everyone to know that he's not a foreign agitator trying to defy the Chinese Communist Party.
updated 7:13 AM EDT, Fri October 17, 2014
A smuggler in Dandong, a Chinese border town near North Korea, tells CNN about the underground trade with North Korean soldiers
updated 1:11 AM EDT, Tue October 28, 2014
Yenn Wong got quite a surprise one morning earlier this month when she found out an exact copy of her Hong Kong restaurant had opened in China.
updated 11:15 PM EDT, Tue October 14, 2014
When I first came across a "virtual lover" service on e-commerce site Taobao, China's version of Amazon, I thought it was hype.
updated 9:15 AM EDT, Tue October 14, 2014
Each year Yi Jiefeng does what she can to stop China turning into a desert.
updated 10:54 AM EDT, Mon October 13, 2014
As its relationship with the West worsen, Russia is pivoting east in an attempt to secure business with China.
updated 10:29 PM EDT, Tue October 7, 2014
Aspiring Chinese comics performing in Shanghai's underground comedy scene hope to bring stand-up to the masses.
updated 12:54 PM EDT, Tue September 30, 2014
Liu Wen is one of the world's highest-paid models and the first Chinese face to crack the top five in Forbes' annual list of top earners.
updated 7:44 AM EDT, Fri October 3, 2014
Cunning wolf? Working class hero? Or bland Beijing loyalist? C.Y. Leung was a relative unknown when he came to power in 2012.
updated 7:25 AM EDT, Thu October 2, 2014
 A man uses his smartphone on July 16, 2014 in Tokyo, Japan. Only 53.5% of Japanese owned smartphones in March, according to a white paper released by the Ministry of Communications on July 15, 2014. The survey of a thousand participants each from Japan, the U.S., Britain, France, South Korea and Singapore, demonstrated that Japan had the fewest rate of the six; Singapore had the highest at 93.1%, followed by South Korea at 88.7%, UK at 80%, and France at 71.6%, and U.S. at 69.6% in the U.S. On the other hand, Japan had the highest percentage of regular mobile phone owners with 28.7%. (Photo by Atsushi Tomura/Getty Images)
App hopes to help those seeking a way out of China's overstrained public health system.
updated 8:20 PM EDT, Thu October 2, 2014
Yards from pro-democracy protests, stands the Hong Kong garrison of the People's Liberation Army (PLA), China's armed forces.
ADVERTISEMENT