Bird Flu can infect people via upper airway: HK experts

[wdcare]

From Reuters:

http://today.reuters.com/news/artic...FECTION.xml&WTmodLoc=NewsHome-C3-healthNews-2

(Full article at link above)

Bird flu can infect people via upper airway: expert
Fri Feb 2, 2007 6:51am ET

By Tan Ee Lyn

HONG KONG (Reuters) - Leading scientists in Hong Kong have found that the H5N1 bird flu virus can infect cells in the upper airway of humans and need not penetrate deep in the lungs to cause infection.

A study by scientists based in the United States in 2006 suggested that H5N1 could not infect people easily because it had to first lodge itself deep inside the lungs, where it binds more easily to certain receptors called the alpha 2-3.

But in an article published in the January issue of the journal Nature Medicine, scientists from the University of Hong Kong found that the virus could infect the nasopharynx, an area behind the nose and above the soft palate, and the throat.

"On the earlier hypothesis, the virus has to go deep into the lungs to infect anybody but our research suggests that is not the case. The virus can get a foothold in the upper respiratory tract, it doesn't have to get deep down into the lungs," microbiology professor Malik Peiris told Reuters late on Friday...


"Even in the upper respiratory tract (where) the alpha 2-3 receptor seems to be lacking, the H5N1 can still infect the cells ... so it raises the question of whether there may be other receptors the virus is using and highlights the point that further study is needed."


Reuters 2007. All Rights Reserved.

 

[gsgs]

Re: Bird Flu can infect people via upper airway: HK experts

another myth, which didn't hold.

1) no h2h
2) no respiratory spread, only fecal-oral
3) only in the lower airways

---only large droplets
---only high initial load
---only people with certain genetics


---just less likely than with H3N2, reason unknown. Situation might change

 

[JohnW]

Re: Bird Flu can infect people via upper airway: HK experts

This article, and the one on the BBC last week, raise a question I haven't seen addressed. Both articles note that H5N1 is increasingly found in the upper respiratory tract. Here is the issue: As I recall, in 1997 in Hong Kong, the virus clinically manifested itself in humans primarily as diarrhea. At the time, avian flu was primarily found in birds via cloacal swabs. In 2003, H5N1 was found deep in the lungs of humans. Now it appears in the upper respiratory tract of humans. At the same time, scientist have had to move to nasal and throat swabs in birds to detect the virus...it has changed in birds as well! So the question is: Is there any evidence for B2H2B2H2??? Do changes in the virus over time indicate that H5N1is passing back and forth between birds and humans, and becoming better adapted as a result?