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Posted in Our Blog on November 21, 2024
Scientists from the University of Wisconsin at Madison and Japan discover bird flu in humans is contagious and is fatal in animals.
The unspoken thought here is that humans are in fact, animals.
So far, there have not been any confirmed reports of human-to-human bird flu transmission. But laboratory results indicate that the likelihood of this may change. Additionally, the impact on animals that humans come in contact with will be significant.
University of Wisconsin at Madison scientist, along with some from Japan isolated a sample from a sick dairy worker? Lung cells were studied. They also took a sample from the eye of an infected dairy worker who experienced conjunctivitis after exposure to cows infected with bird flu and performed a series of tests.
Why?
Several reasons.
First, they wanted to understand whether the virus is capable of replicating within the human respiratory system.
Second, they wanted to determine if once replicated, the virus could spread further to certain animals. Or even humans.
What they discovered was somewhat expected, but devastating, nonetheless.
The biggest question is whether or not human-to-human transmission is possible. To do so, the virus must be able to replicate in the human body.
After further investigation, researchers found a specific type of mutation (PB2-E627K) also found in H5N1 viruses that replicate in mammals.
So yes, the virus could potentially replicate in the human body.
Not good.
On to question number two.
Experiments determined that virus from human cornea and lung cells were able to infect mouse tissues. In fact, the bird flu virus was able to infect 15 different tissues.
The highest levels of infection were observed in respiratory tissues.
Ferrets are often used for influenza studies in humans. This is because ferrets are one of the best animal models for the illness. Clinical signs of disease as well as modes of transmission are similar between the two mammals.
When exposed to human bird flu samples, all ferrets in the study died within five days.
Tissue sampling revealed the presence of virus in all tissue types. Again, the highest amounts of virus were found in respiratory tissues.
Previous studies were performed in similar experiments with bovine acquired bird flu samples.
While infection rates were similar to those of bird flu in humans, and infections were severe, bird flu from cows was not as lethal as bird flu from humans.
Not only have scientists discovered that bird flu is contagious in humans and likely transmissible to other animals. But bird flu in humans is fatal in certain other animals.
Could it be fatal in humans?
There is not enough evidence to support that.
Meanwhile, scientists work to understand how sensitive bird flu transmission is between animals.
To measure how easily bird flu is transmissible through respiratory droplets, scientists placed cages of healthy ferrets next to cages of ferrets infected with different doses of virus obtained from the dairy worker.
All directly infected ferrets died within six days.
Ferrets in neighboring cages became sick. From around 17% to 33% of ferrets in those adjacent cages showed infection from respiratory droplets.
”Based in these observations, every effort should be made to contain HPAI (highly pathogenic avian influenza} H5N1 outbreaks in dairy cattle to limit the possibility of further human infections,” wrote investigators in Nature.
California, a major area for dairy cow farms, has been hit pretty hard with cases of bird flu in humans.
The state recently added another probable case of bird flu in humans. The patient sample tested positive by a local lab. However, confirmatory testing at the Centers for Disease Control and Prevention (CDC) laboratory was negative.
Despite updated California state counts indicating at least 27 cases of bird flu from cows in humans, risk status on the California Department of Health Bird Flu website indicates the current risk to the public remains low.
This is likely because statistics favor the spread of bird flu mostly on those who interact with infected dairy cows, poultry, or wildlife. No person-to-person transmission in California has been observed.
According to the CDC, there have been 53 confirmed human cases of bird flu. Broken down, 31 of those cases came from dairy cows, 21 from poultry, and one with an unknown origin.
As of November 18, 2024, there have been 48 states with poultry bird flu outbreaks across the United States. So far 108,412,209 poultry birds have been affected.
That is over 100 million!
On the dairy cow side, 15 states have been impacted. So far this includes 549 dairy cow herds as of November 18, 2024.
In response to the potential threat to humans, additional research is underway to determine if current antivirals on the market could be effective against this bird flu virus from dairy cows.
The results are promising.
The National Institute of Allergy and Infectious Diseases (NIAID) indicated that favipiravir, baloxavir marboxil, and zanamivir were effective. However, the virus was less sensitive to oseltamivir.
Unfortunately, there are limited preventative measures you can take to reduce your risk of bird flu. There are, however, a few things you can do to reduce your risk.
Unless you work in the industries, avoiding dairy cows and poultry farms is a potential way to reduce your risk of bird flu exposure.
While additional research is needed to determine if bird flu passed into cow’s milk is infectious to humans, it is best to drink pasteurized milk. Pasteurization is a heat treatment process that inactivates bacterial, viral, and parasitic pathogens.
If you’d like to know more about food safety topics in the news, like “Scientists Discover Bird Flu in Humans is Contagious and Fatal in Animals,” check out the Make Food Safe Blog. We regularly update trending topics, foodborne infections in the news, recalls, and more! Stay tuned for quality information to help keep your family safe, while The Lange Law Firm, PLLC strives to Make Food Safe!
By: Heather Van Tassell (contributing writer, non-lawyer)