Health Day - ONLINE EDITION

China Bird Flu Appears to Have Spread From Person to Person

Single reported case does not mean pandemic is likely, although vigilance is needed, experts say

  • Print

TUESDAY, Aug. 6 (HealthDay News) -- The first reported human-to-human transmission of the deadly H7N9 bird flu has occurred in eastern China.

The illness first killed a 60-year-old man exposed to live poultry and then his previously healthy 32-year-old daughter who had been caring for him.

But dozens of other people exposed to the two flu victims did not fall ill, according to a new report published Aug. 6 in the journal BMJ, leading epidemiologists to conclude that the virus's ability to transmit itself between humans is limited at this point.

"To date, it hasn't been sustainable. It's only been one jump, from chickens to humans," said Dr. Marc-Alain Widdowson, who leads the international epidemiology and research team in the U.S. Centers for Disease Control and Prevention's Influenza Division. "It hasn't gone from chicken to human to human to human to human. That's the concern. That's when we have a pandemic on our hands."

The virus, which was first identified in February, has killed one-third of the people who have contracted it. By the end of June, 133 cases had been reported, resulting in 43 deaths.

New cases have slowed to a trickle since May, World Health Organization spokesman Gregory Hartl said. This is likely due to warmer weather in China and the closure of some live bird markets in the affected provinces.

H7N9 has raised concerns among epidemiologists because it can bind to both human and bird cells, unlike the earlier H5N1 bird flu. This increases the possibility that the virus can more easily jump from birds to humans.

"This virus, contrary to H5N1, does seem to have a better affinity to human receptors, so there is a chance that this virus may affect humans more easily," Widdowson said.

The virus attaches itself to cells in the windpipe and lungs, infecting even cells lodged deep in the respiratory system.

A handful of suspected human-to-human transmissions have been noted by epidemiologists since the virus was identified, but this is the first to be published, Hartl said.

The affected father regularly visited a live poultry market and became ill five to six days after his last exposure to poultry, according to the Chinese epidemiologists who wrote the BMJ report.

He was hospitalized on March 11 and transferred to the intensive-care unit on March 15 when his symptoms became worse. He died of multiple organ failure on May 4.

His adult daughter had no known exposure to live poultry but remained by her father's bedside for days after he fell ill, the researchers said. The report noted that she managed his oral hygiene and gave other care without using any personal protective equipment.

She developed symptoms six days after her final contact with her father and was hospitalized on March 24.

Doctors transferred her to the ICU on March 28, and she died of multiple organ failure on April 24.

Researchers found two almost genetically identical virus strains in each patient, suggesting transmission from father to daughter.

Public health officials tracked down 43 close contacts of both the father and daughter, but all tested negative for H7N9 infection.

"This paper is reassuring because many of the other people in contact with the cases did not contract the virus," said Dr. Jeff Duchin, a spokesman for the Infectious Diseases Society of America. "Also, the researchers did not find any genetic changes that would suggest that the virus that did transmit from human to human had adapted or displayed changes that would suggest it would be more likely to cause a human pandemic."

Duchin concluded that the report "doesn't change the threat level."

"This confirms what a lot of people already believed, that there are rare cases of human-to-human transmission," said Duchin, a professor of allergy and infectious disease and an adjunct professor of epidemiology at the University of Washington's School of Public Health, in Seattle.

Nonetheless, the CDC and WHO will continue to monitor the virus's progress, Widdowson and Hartl said.

"It would be wrong for people to let down their guard now. We need to be vigilant, and we need to keep watching for cases," Hartl said. "It's out there still. That we know, because we haven't found the source definitively. So we need to expect to see more cases."

More information

To learn more about H7N9 bird flu, visit the U.S. Centers for Disease Control and Prevention.

Fact Check

Fact Check

Have you found an error, or know of something we’ve missed in one of our stories?
Please use the form below and let us know.

* Required
  • Please post the headline of the story or the title of the video with the error.

  • Please post exactly what was wrong with the story.

  • Please indicate your source for the correct information.

  • Yes

    No

  • This will only be used to contact you if we have a question about your submission, it will not be used to identify you or be published.

  • Cancel

Having problems with the form?

Contact Us Directly
  • Print

You can comment on most stories on winnipegfreepress.com. You can also agree or disagree with other comments. All you need to do is be a Winnipeg Free Press print or e-edition subscriber to join the conversation and give your feedback.

You can comment on most stories on winnipegfreepress.com. You can also agree or disagree with other comments. All you need to do is be a Winnipeg Free Press print or e-edition subscriber to join the conversation and give your feedback.

Have Your Say

New to commenting? Check out our Frequently Asked Questions.

Have Your Say

Comments are open to Winnipeg Free Press print or e-edition subscribers only. why?

Have Your Say

Comments are open to Winnipeg Free Press Subscribers only. why?

The Winnipeg Free Press does not necessarily endorse any of the views posted. By submitting your comment, you agree to our Terms and Conditions. These terms were revised effective April 16, 2010.

letters

Make text: Larger | Smaller

LATEST VIDEO

Drew Willy says team couldn't get anything going

View more like this

Photo Store Gallery

  • PHIL.HOSSACK@FREEPRESS.MB.CA 101130-Winnipeg Free Press Columns of light reach skyward to the stars above Sanford Mb Tuesday night. The effect is produced by streetlights refracting through ice crystals suspended in the air on humid winter nights. Stand Up.....
  • Aerial view of Portage and Main, The Esplanade Riel, Provencher Bridge over the Red River, The Canadian Museum for Human Rights and The Forks near the Assiniboine River, October 21st, 2011. (TREVOR HAGAN/WINNIPEG FREE PRESS) CMHR

View More Gallery Photos

Poll

What's your take on a report that shows violent crime is decreasing in Winnipeg?

View Results

View Related Story

Ads by Google