Re: Dairy flu may be colliding with seasonal flu in California

On 10/17/2024 1:43 PM, RonO wrote:

https://www.politico.com/news/2024/10/17/avian-flu-california-pandemic- threat-00184027
 When the dairy infections had spread to around 9 states the CDC gave up because they claimed that they could not figure out how states that did not get cattle were being infected.  My take is that they always understood that dairy workers were taking the virus to other states, but they never wanted to acknowledge that fact.  They knew that the virus only survived on equipment for around 24 hours, and on skin and clothing for less than 30 minutes, so infected animals or people were the obvious transmission vectors to poultry farms and other dairies that did not exchange cattle.  Dairy workers shedding live virus could obviously infect cattle, and likely other people.
 The CDC stopped trying to contain the spread of the dairy influenza, refused to start contact tracing and testing, and decided to only monitor the infection in 2 states (Texas and Michigan, later expanded to Colorado and now California).  They did not try to identify all the infected herds in Texas and Michigan, they just "monitored" the states response to the epidemic.  They claimed to increase their human surveillance across the nation with the hope of detecting when the virus adapted to better infect humans and started to spread in the human population.  They claimed that if they detected the evolution to human infection early enough that they could try to contain the infection and prevent the next pandemic.
 This article is worried about the mixing of seasonal flu with the dairy flu.  A lot of dairy workers are likely being infected, and if they get infected with both the dairy and seasonal viruses at the same time you can get recombinant virus that share portions of their genomes with the two strains.  The article notes that the swine flu of 2009 with a higher mortality rate than usual was a combination of 4 influenza strains that included swine, avian, and human adapted influenza virus.  The main worry about the dairy H5N1 is that the original Asian strain had a 50% mortality of infected humans, but the North American H5N1 is a recombinant with an American avian influenza strain (about half of it's genome remains the same as the Asian H5N1) and has only exhibited mild symptoms in infected humans.  The fear is that a recombinant with a human adapted influenza may make the H5N1 dairy virus more pathogenic.
 There are over 17,500 dairy workers in California, but the CDC is only sending 5,000 seasonal flu vaccination doses.  Over 9% of the California dairy herds have been infected so far, but that is a low count because they are still finding more infected herds by contact tracing.
 What they need to do is to collect eye and nasal samples from all the dairy workers that are vaccinated to get a base line number for current infection rates.  I am assuming that they will be vaccinating infected farms first.  This will not detect those that have already been infected and recovered, but should identify those still shedding live virus.  If they want to do a thorough study they would take blood samples and test for antibodies against the California H5 gene product.  It is already known that this gene has 2 to 3 more amino acid substitutions relative to the original dairy virus detected in March, so they would have to make antibodies against the current H5 gene for their testing.
 It should be noted that the Missouri case also had 2 amino acid substitutions in the H5 gene that the CDC determined to reduce neutralizing activity of the current H5 vaccine strain antibodies, so they needed to make a synthetic H5 gene with those substitutions in it to try to identify dairy virus antibodies in the Missouri patient contacts that showed symptoms.  This means that the H5 vaccine that the CDC decided to stock pile as part of their "rapid" response to the next pandemic is likely worthless.  They really need to work harder at containing the dairy infection and preventing the evolution of the virus to better infect humans.  If the virus is allowed to evolve in a populated state with international airports like California there likely is no "rapid" response that will prevent the next world wide pandemic.
 I should probably note that they call recombinant influenza virus "reassortment" virus because usually whole chromosomes are swapped between virus strains.  Influenza has 8 RNA chromosomes or "RNA segments".
 Ron Okimoto
 

https://www.latimes.com/environment/story/2024-10-22/how-did-h5n1-bird-flu-get-into-california-dairy-farms
This LA Times article has some variant information about the California infection.  You may have to subscribe to see the article.
The article claims that there are "roughly 1,300 dairy farms" and not the "more than 1,100" quoted by all the other articles so far.  the 1.7 million dairy cattle stays the same.
The article has speculation that the virus came from Idaho and the claim by California officials is that the virus is most similar in sequence to Idaho and not Colorado as was first reported.  No one can verify this very well because the USDA puts out the sequence, but only gives the date of the sequencing, and does not give the location that the sample was collected (the dairy virus samples are all listed as being collected in the USA).
Apparently the most likely incident is when a California dairy farm sold some cows to an Idaho farm, but the Idaho farm did not like the cows so they sent them back.  This occurred in late July or early August.  This sounds like there has not been enough time to infect so many herds.  It likely takes the infection a couple weeks to establish in a herd before it can be taken to another herd by cattle or workers.  This infection story is likely why they first believed that they had limited the infection to half a dozen farms in late August, but they were very wrong, and it looks like around a hundred herds were already infected. An alternative is that the infection of dairy workers shedding virus is much higher than everyone thinks, and is the reason that California was able to detect so many infected herds so rapidly by contact tracing. Previous work with H5N1 avian influenza among poultry workers before the start of the dairy epidemic found that some asymptomatic poultry workers that had worked with infected birds did have H5 antibodies indicating infection, but they did not produce neutralizing antibody levels.  All the workers need is a mild infection and be shedding virus from, likely, their eyes to infect the cattle that they are handling.
Once a sequence analysis is done where the samples are properly labeled they can likely determine how the infection spread through the California dairy herds as they did with Texas, but did not bother to do for the other states.  If they think that they know the first farm infected the sequence analysis can confirm that because the virus evolves very rapidly.
Ron Okimoto