Post Reply - H5N1/flu (other types)

Nature

   https://afludiary.blogspot.com/2024/11/cdc-updated-results-on-texas-h5n1-virus.html or https://afludiary.blogspot.com/2024/11/cdc-updated-results-on-texas-h5n1-virus.html ;-
This week the Journal Nature published two concerning studies on H5N1 in ferrets. 
The first, which I covered in Nature: A Human Isolate of Bovine H5N1 is Transmissible and Lethal in Animal Models, found the virus was lethal in mice and ferrets, and that it `. . .could be transmitted through the air between separated ferrets and might be capable of binding to and replicating in human respiratory tract cells.'
A second study, which repeats the animals experiments described last June, was titled:
Transmission of a human isolate of clade 2.3.4.4b A(H5N1) virus in ferrets
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Yesterday the CDC published a summary of findings from this repeated research which provides additional details and somewhat different results (e.g. 66% droplet transmission between ferrets vs. 33% in the original report).
I've reproduced their summary below (bolding mine).  I'll have a brief postscript after the break.
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The A/Texas/37/2024 virus spread efficiently between ferrets in direct contact (100%) but did not spread efficiently between ferrets via respiratory droplets (i.e., droplets containing virus released into the air from coughs or sneezes) or by fomites (i.e., contaminated surfaces) (66%). This is different from what is seen with seasonal influenza viruses, which do spread efficiently via respiratory droplets and fomites in ferrets (100%).
 Results from this ferret study helped inform CDC's early risk assessments of the potential impact of these viruses on human health.
The results suggest this virus has the potential to cause severe illness in people and reinforce the importance of protective measures among people with exposure to infected animals and for public health and agriculture communities to continue to work together to contain this outbreak. 
The preliminary results of this study reported in June 2024, are available at CDC Reports A(H5N1) Ferret Study Results | Bird Flu | CDC.
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Conclusion and risk assessment

Overall, the cumulative results of studies in ferrets using the A(H5N1) virus from a human case in Texas suggest the virus still is not capable of spreading efficiently among people via respiratory droplets compared to seasonal influenza viruses. These findings highlight the importance of continued surveillance to monitor these kinds of changes in circulating A(H5N1) viruses. More information on ferret studies is available at CDC Reports A(H5N1) Ferret Study Results | Bird Flu | CDC.
          (Continue . . . )

This updated report, along with the findings from the other Nature study this week, paint a picture of an H5N1 virus better adapted than what we've seen reported from other states. This first Texas case is admittedly a bit of an outlier, in that the PB2-E627K and PA-K142E mutations have not been reported since. 
Nothing says they couldn't turn up tomorrow in another case, but for now (as far as we know) this tag-team of mutations has not been repeated. 
But every time the virus infects a new host (avian or mammalian) it has another opportunity to toss the genetic dice - and the more chances we allow it - the greater the chances are it will come up a winner.
Which is why - even though it may be presenting as a mild illness in humans today - we can't assume it will remain mild forever. 
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DJ-The big worry is we are in a running train...a developing proces...Lots of H5N1 cases are out of sight. 

https://flutrackers.com/forum/forum/united-states/h5n1-tracking-af/oregon/999615-oregon-human-h5n1-cases-2024-travelers-from-washington-state-accounted-for-there?view=stream or https://flutrackers.com/forum/forum/united-states/h5n1-tracking-af/oregon/999615-oregon-human-h5n1-cases-2024-travelers-from-washington-state-accounted-for-there?view=stream ;
Treyfish replied
October 31, 2024, 09:26 PM
OHA reports 3 humans with bird flu traveled to Oregon during Washington outbreak

by: Aimee Plante

Posted: Oct 31, 2024 / 03:20 PM PDT

Updated: Oct 31, 2024 / 04:41 PM PDT

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PORTLAND, Ore. (KOIN) – A week after Washington reported human cases of bird flu in the state, officials have announced that three of those cases had traveled to Oregon during their infection and were monitored during their stay.
All three cases of highly pathogenic avian influenza (HPAI) were reported in Washington after they were exposed to poultry that tested positive for the virus on Oct. 15. As of Thursday, Oct. 31, there have been nine total cases in Washington — including those who had traveled to Oregon...

Oregon Health Authority officials say the cases have returned to Washington and will continue to be monitored by Washington health staff until 10 days following their last exposure.

DJ...WHY ????