Avian flu - A new study led by a team from the University of Maryland

[pinball1970]

TL;DR Summary

The team concluded that the avian flu will probably become endemic, which could affect food security and the economy.

Unlike the 2015 outbreak of avian flu (H5N8), the outbreak seen in late 2021 (H5N1) has caused mass mortality for wild birds, which makes the highly pathogenic virus more difficult to wipe out. “Unlike H5N8, this disease is heavily impacting wild birds,” said Johanna Harvey, lead author of the study and a postdoctoral researcher at the University of Maryland.

Article here.

https://www.theguardian.com/world/2023/apr/19/avian-flu-strain-deadly-endemic-study

CDC report here

https://www.cdc.gov/flu/avianflu/spotlights/2022-2023/h5n1-technical-report.htm

There is an associated paper in conservation Biology also. (no access to that)

Phys.org had an article along similar lines here

https://phys.org/news/2023-04-california-condor-samples-positive-h5n1.html

Some back ground.

Influenza A viruses are classified by subtypes based on the properties of their hemagglutinin (H or HA) and neuraminidase (N or NA) surface proteins. There are 18 different HA subtypes and 11 different NA subtypes. Subtypes are named by combining the H and N numbers – e.g., A(H1N1), A(H3N2).

https://www.cdc.gov/flu/avianflu/h5n1-animals.htm

 

[StatGuy2000]

Interesting and concerning news.

I should point out that various different avian flu strains have been circulating and been endemic for decades, and that I would suspect that the birds that survive the current H5N1 avian flu strain will develop immunity to this current strain.

As I see it, the concerns are the following:

1. The susceptibility of certain species of wild birds whose overall population is already distressed (due to habitat loss, climate change, etc.) and what impact a deadlier, endemic avian flu will have on these populations.

2. The susceptibility of farmed birds (chickens, turkeys, ducks, geese) and the impact the losses of these birds would have on both economic factors and in terms of food security.

3. The potential risk that this avian flu could mutate to become more transmissible to humans and other mammalian species (jumping the species barrier), thus sparking a new flu pandemic.

The above concerns could be mitigated if a vaccine is developed for the H5N1 avian flu for both birds and humans. From what I have read, there are several candidates that are currently being investigated.

 

[pinball1970]

Interesting and concerning news.

I should point out that various different avian flu strains have been circulating and been endemic for decades, and that I would suspect that the birds that survive the current H5N1 avian flu strain will develop immunity to this current strain.

As I see it, the concerns are the following:

1. The susceptibility of certain species of wild birds whose overall population is already distressed (due to habitat loss, climate change, etc.) and what impact a deadlier, endemic avian flu will have on these populations.

2. The susceptibility of farmed birds (chickens, turkeys, ducks, geese) and the impact the losses of these birds would have on both economic factors and in terms of food security.

3. The potential risk that this avian flu could mutate to become more transmissible to humans and other mammalian species (jumping the species barrier), thus sparking a new flu pandemic.

The above concerns could be mitigated if a vaccine is developed for the H5N1 avian flu for both birds and humans. From what I have read, there are several candidates that are currently being investigated.

Just following on from your last point.

https://phys.org/news/2023-05-vaccine-authorized-emergency-california-condors.html

 

[Astronuc]

I heard about the wildlife scientists innoculating California condors.

 

[Astronuc]

New research indicates that the flu (Avian flu (H5N1)), which has killed off hundreds of thousands of wild birds, is one of the most devastating disease outbreaks in history. Vox reported that the disease has spread across five continents and hundreds of species, including endangered ones like the California condor, which classifies it as a “panzootic” — a pandemic among animals.

Avian flu typically causes death only among domesticated birds, like ducks and chickens, killing up to 90% of the flock within an outbreak. But this time, it’s different.

https://www.yahoo.com/news/research-shows-devastating-virus-one-110000717.html

The biology of the virus has caused it to attack wild species and even mammals.

This variant of H5N1 is apparently infecting mammals as well as wild birds and domestic poultry.

 

[Laroxe]

I think the Yahoo article is not really very accurate, the H5N1 variant was identified in 2014, this is classified as a highly pathogenic strain (to birds) and is one of several strains currently circulating. Avian flu is something of a master of changing its antigenic properties by genetic reassortment, each strain often having different substrains. The Asian strain H5N1 being antigenically distinct from the strain found in the America's, I don't know why it says the biology causes it to attack wild birds, it does of course, its a bird disease and is primarily spread by wild birds. Avian flu has always had considerable evolutionary potential none of this is new, and the substrains seen to infect other animals, including humans, usually have distinct genetic signatures. The subtypes that spread easily among animal populations tend to be very specific The current H5N1 strains do not spread easily among humans, the cases all tend to have had a high level of exposure, it is the H1N1 strain of avian flu which continues to cause most problems to humans. While most birds appear susceptible, It seems that aquatic birds serve as the main reservoirs for the virus, with some (ducks in particular) showing increased tolerance of the virus.

It's difficult to know, how they come by their numbers, it's routine practice to cull populations known to have come into contact with one of the highly pathogenic strains, this is true even when there is no evidence of infection. There is of course increased monitoring of wild birds because of the recognised risk, the 100's of thousands suggested is a guess. In fact, avian flu like other forms is seasonal and most of the world is currently in a low risk period. The disease is spread by wild birds, domesticated birds have to come into contact with infected material. The economic threat mentioned is also interesting, it's difficult to know why prices of eggs went up so much in the USA as the disease had little real impact on domestic production. There were similar rises in the UK, but they were attributed to the reluctance of supermarkets to give producers a fair price. In many parts of the world poultry meat actually fell in price, I suspect because of the restrictions on movement, it was our own prevention efforts rather than the disease itself.

https://www.woah.org/app/uploads/2023/06/hpai-situation-report-20230626.pdf

https://www.thepoultrysite.com/arti...nza-h5n1-has-affected-world-poultrymeat-trade

Its interesting the article uses the opportunity to criticise compact rearing practices, while its true that this would facilitate the spread if there was already infection in the flock, putting poultry under cover is a fairly standard way to reduce the risk of exposure.

There is lots of info at: https://www.cdc.gov/flu/avianflu/index.htm

 

[pinball1970]

Article this week

https://phys.org/news/2024-03-bird-flu-dairy-cows-texas.html


From the Animal and plant health inspection service.

"At this stage, there is no concern about the safety of the commercial milk supply or that this circumstance poses a risk to consumer health. Dairies are required to send only milk from healthy animals into processing for human consumption; milk from impacted animals is being diverted or destroyed so that it does not enter the food supply."


https://www.aphis.usda.gov/aphis/newsroom/news/sa_by_date/sa-2024/hpai-cattle