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They allege that content moderation policies on the social media platforms during the pandemic violated Quebecers' freedom of expression.
Published May 10, 2024 Last updated 3hours ago 3 minute read
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A Superior Court judge has authorized two class-action lawsuits alleging that Facebook and YouTubes content moderation policies during the COVID-19 pandemic violated Quebecers freedom of expression.
The suit against Meta Platforms, which owns Facebook, was brought by Christian Leray, an administrator of the Facebook group for an organization called Rinfo Qubec, which criticized COVID-19 public health measuresand who had posts deleted because the social media platform said they contained misinformation about vaccines.
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In his decision late last month, Justice Lukasz Granosik wrote that given the role Facebook plays in society, it has to take some responsibility for the control it exercises over the content that appears on its platform.
If Facebook carries out censorship, prevents certain people from posting certain information, sanctions them by restricting access to their account and thus hinders the free circulation of ideas, it exposes itself to having to defend its methods, he wrote. Its decision may be well-founded and it may not incur any liability, but the question has been raised and it is clear that the plaintiff has a chance of success on the merits.
In his decision allowing the suit against Google, which owns YouTube, Granosik came to an almost identical conclusion.
In that case, representative plaintiff lose Boies alleges that several videos which claimed that governments and large companies were censoring information about COVID-19 and questioned the efficacy and safety of COVID-19 vaccines were deleted because they violated the platforms policies.
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In his suit against Meta Platforms, Leray alleges that when his posts were deleted on Facebook, his account was suspended for periods ranging from 24 hours to a month, according to the decision.
Leray alleges that Facebook controls the content on its platform, even censoring it, by deleting posts, restricting the accessibility of certain messages by sanctioning their authors, classifying them in a particular way, or by sending or adding warnings, Granosik wrote. Facebook justifies all these measures, now and in the past by its policy of prohibiting disinformation that can cause physical damage or relates false information about COVID-19, or simply because this information was at odds with its community standards.'
Meta Platforms argued against allowing the suit to move forward on the grounds that Leray didnt have a case and that people whose posts were deleted didnt form the type of group that can launch a class action.
Meta argues that it didnt commit any violation of the Charter, because it has no obligation to provide a platform for the expression of any speech and that its platform is private and it can use it as it wishes, or according to its own rules and, finally, that the plaintiff can exercise his freedom of expression in other ways, the judge wrote.
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Google made similar arguments, according to the decision in that case.
The class actions include any Quebec resident whose content was deleted or who was unable to view content deleted by the platforms. They seek a total of $2,000 in damages for anyone who had a censored Facebook post or YouTube video and $1,000 for anyone who was unable to view that content.
William Desrochers, the lawyer representing the plaintiffs in both cases, said that while the companies policies were to delete content that could be harmful, it seems the way they applied it is that people are actually prevented from criticizing the government about COVID-19.
Facebook and YouTube have become the ideal public space if you want to spread a message to other citizens or people around you, he said, and that by opening themselves up to everyone and allowing people to express themselves, the platforms have limited their ability to control that content and determine what ideas are allowed.
While the platforms may have been justified in deleting some of the posts, he said they will have to demonstrate that their actions were reasonable.
Authorization is an early step that shows the case isnt frivolous, Desrochers said, adding that a trial is probably years away.
Google and Meta Platforms did not respond to requests for comment Friday.
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This is a new approach to vaccine development called proactive vaccinology, where scientists build a vaccine before the disease-causing pathogen even emerges.
The new vaccine works by training the bodys immune system to recognise specific regions of eight different coronaviruses, including SARS-CoV-1, SARS-CoV-2, and several that are currently circulating in bats and have potential to jump to humans and cause a pandemic.
Key to its effectiveness is that the specific virus regions the vaccine targets also appear in many related coronaviruses. By training the immune system to attack these regions, it gives protection against other coronaviruses not represented in the vaccine including ones that havent even been identified yet.
For example, the new vaccine does not include the SARS-CoV-1 coronavirus, which caused the 2003 SARS outbreak, yet it still induces an immune response to that virus.
Our focus is to create a vaccine that will protect us against the next coronavirus pandemic, and have it ready before the pandemic has even started, said Rory Hills, a graduate researcher in the University of Cambridges Department of Pharmacology and first author of the report.
He added: Weve created a vaccine that provides protection against a broad range of different coronaviruses including ones we dont even know about yet.
The results are published today in the journal Nature Nanotechnology.
We dont have to wait for new coronaviruses to emerge. We know enough about coronaviruses, and different immune responses to them, that we can get going with building protective vaccines against unknown coronaviruses now, said Professor Mark Howarth in the University of Cambridges Department of Pharmacology, senior author of the report.
He added: Scientists did a great job in quickly producing an extremely effective COVID vaccine during the last pandemic, but the world still had a massive crisis with a huge number of deaths. We need to work out how we can do even better than that in the future, and a powerful component of that is starting to build the vaccines in advance.
The new Quartet Nanocage vaccine is based on a structure called a nanoparticle a ball of proteins held together by incredibly strong interactions. Chains of different viral antigens are attached to this nanoparticle using a novel protein superglue. Multiple antigens are included in these chains, which trains the immune system to target specific regions shared across a broad range of coronaviruses.
This study demonstrated that the new vaccine raises a broad immune response, even in mice that were pre-immunised with SARS-CoV-2.
The new vaccine is much simpler in design than other broadly protective vaccines currently in development, which the researchers say should accelerate its route into clinical trials.
The underlying technology they have developed also has potential for use in vaccine development to protect against many other health challenges.
The work involved a collaboration between scientists at the University of Cambridge, the University of Oxford, and Caltech. It improves on previous work, by the Oxford and Caltech groups, to develop a novel all-in-one vaccine against coronavirus threats. The vaccine developed by Oxford and Caltech should enter Phase 1 clinical trials in early 2025, but its complex nature makes it challenging to manufacture which could limit large-scale production.
Conventional vaccines include a single antigen to train the immune system to target a single specific virus. This may not protect against a diverse range of existing coronaviruses, or against pathogens that are newly emerging.
The research was funded by the Biotechnology and Biological Sciences Research Council.
Reference: Hills, R A et al: Proactive vaccination using multiviral Quartet Nanocages to elicit broad anti-coronavirus responses. Nature Nanotechnology, May 2024. DOI: 10.1038/s41565-024-01655-9
By Prabhat Prakash & Prarthana Sharma
New Delhi: Global public health systems continue to face difficulties as a result of the mutating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants in the ongoing fight against COVID-19. FLiRT, or fast-transmitting, low-immunity, rapid-transforming, is the most recent strain of SARS-CoV-2 to enter the constantly changing field. FLiRT has attracted a lot of interest from the scientific and medical communities due to its distinctive set of properties.
continued below
Explaining the severe symptoms aligned with the variant, Dr Harshad Limaye, Senior Consultant, Internal Medicine, Nanavati Max Super Speciality Hospital, said, "According to recent scientific assessments, the FLiRT variant, which is categorised as an Omicron subvariant, does not appear to display a significantly elevated severity of sickness in comparison to other recent Omicron sub-variants. Although media and publications from the US have acknowledged its emergence, there isn't any strong evidence to support the theory that FLiRT is linked to higher disease severity. This finding is consistent with the larger pattern of Omicron variations, in which transmissibility frequently outweighs severity. Nevertheless, further study and observation are necessary to completely comprehend FLiRT's influence and any possible subtleties in its behaviour."
FLiRT variant symptoms
FLiRT does not provide any novel patterns or features of disease. On the other hand, it presents with symptoms that are typical with COVID-19 infections. Headache, fever, body aches, cough, and symptoms similar to a cold are characteristic of these symptoms. Even while each person's symptom profile may differ, keeping an eye out for these common signs is still crucial for quickly identifying and treating possible infections.
Dr Tandekar added, "This variant's symptoms are similar to those of other variations, such as Omicron, and include a variety of typical symptoms like fever, chills, runny or stuffy nose, headache, weariness, sore throat, cough, muscular or body aches, and loss of taste and smell. When these warning signals appear, it's critical to start covid testing right away because early diagnosis can help with timely response and containment measures. Fast testing is essential to correctly identify and manage cases, enabling efficient public health interventions and preventing additional transmission throughout communities, given the overlap in symptoms with earlier variations."
Compared to other COVID-19 strains, FLiRT, a variation of the Omicron lineage, does not introduce any unique symptomatology or sickness patterns. Instead, its clinical manifestation closely resembles the recognised symptoms that are frequently connected to the illness.
Headaches, fever, body aches, coughing, and cold-like symptoms are common symptoms of FLiRT infection and can be experienced by individuals infected with different strains of the virus. The difficulty of clinically distinguishing FLiRT from other circulating variations based just on symptomatology is highlighted by the consistency in symptom manifestation, underscoring the significance of diagnostic testing and epidemiological background in accurately identifying and managing cases.
FLiRT transmissibility
The possibility of enhanced transmissibility over previous Omicron sub-variants is one noteworthy feature of FLiRT. As the virus continues to evolve, this tendency toward increased transmissibility is frequently seen with newer forms. It's crucial to remember that greater transmissibility does not always equate to greater death rates. Following current public health recommendations is crucial to reducing the spread of FLiRT and its variations. This includes donning masks in crowded areas or medical facilities, social distancing, making sure immunisations are current, and washing hands frequently.
Dr Ujjwal Parakh, Senior Consultant, Department of Chest Medicine, Sir Ganga Ram Hospital, shared, Relief and caution are provided by the appearance of a new version that is more transmissible than its predecessors, like the Omicron variant, but less severe. The data that is now available indicates that this variation causes fewer severe cases and hospitalisations, even though it may spread more quickly. Thus, there is no need for fear, even though it is imperative to continue the preventive measures put in place during the Omicron spike, such as mask-wearing, social separation, and vaccine campaigns. Rather, a cautious strategy centred on monitoring and following public health recommendations can help slow the spread of this novel variation while guaranteeing that healthcare systems continue to be robust in the face of changing difficulties."
The FLiRT variant, like other recent variants, might be more transmissible than previous Omicron sub-variants. There might not be a rise in death rates. Following the most recent public health recommendations, donning masks in crowded areas or medical institutions, making sure immunisations are current, and upholding proper cleanliness are examples of preventive actions.
Dr John Muchahary, Consultant, Interventional Pulmonology, Manipal Hospital Goa, said, It is alarming that FLiRT has emerged, as it may be more transmissible than earlier Omicron sub-variants. This underscores the urgent need to take preventative action to slow the spread of the virus. Increasing testing and surveillance, adhering strictly to public health norms, and exercising increased vigilance are all necessary to support our efforts. Together, we can stop the spread of FLiRT and protect public health by being watchful, according to advised procedures, and quickly detecting and isolating patients."
Preventive measures
Maintaining vigilant monitoring and following preventive measures are crucial to guard against major sickness caused by FLiRT and its variations, considering the dynamic nature of the pandemic. People should continue to take great care to abide by public health recommendations, especially when it comes to donning masks in crowded settings and when they are ill. Infection control also requires using social distancing techniques and upholding proper hand hygiene. Those who exhibit COVID-19-like symptoms should immediately remove themselves from social situations and seek medical attention as needed.
Dr Limaye said, Following public health guidelines continues to be crucial in order to reduce the risk of serious illness, especially in light of the advent of the FLiRT variation. Using masks with caution, especially in crowded areas or when exhibiting symptoms, is an important way to prevent the spread of the infection. Maintaining social distance as a regular habit lowers the chance of exposure by further limiting the variant's potential to propagate. When combined with strict hand hygiene, these precautions strengthen defences against infection. Those who are experiencing symptoms should take immediate action; they should advocate for self-isolation and medical consultation to promptly address any possible health concerns. People can help protect public health as well as their own health by strictly following these principles in the face of the constantly changing viral landscape.
Dr Muchahary added, "Proactive steps are essential to protect individual and societal health in the face of the FLiRT virus. The best line of defence is vaccination, with booster shots suggested to bolster immunity over time. But in addition to immunisation, following basic public health guidelines is still crucial. Three key tactics for reducing the danger of transmission are wearing masks consistently, washing your hands thoroughly, and keeping your distance from others. In addition to providing individual protection, these actions strengthen the resilience of the community as a whole, halting the spread of FLiRT and reducing any potentially dangerous health effects.
Age groups at risk
There is an increased risk of severe sickness from FLiRT and other variations in some demographic groups, such as the elderly and those with pre-existing health disorders like diabetes, asthma, COPD, and other immune-related issues. It is essential to be on guard and take particular care to reduce exposure for these susceptible groups. Maintaining current immunisations and following recommended preventive measures are crucial tactics to guard against serious consequences.
Dr Limaye mentioned, Elderly people and those with pre-existing medical diseases such as diabetes, COPD, asthma, and immune-related disorders need to take extra precautions and take an active role in their health. As they are more susceptible to infections, especially respiratory diseases like COVID-19, it is critical that they maintain current vaccination records. Strict adherence to preventive measures can also considerably lower their chance of catching infectious diseases, such as mask use, proper hand hygiene, and keeping physical distance. They can protect their health and reduce the risk of serious sickness or consequences by keeping a close eye on their condition, getting care quickly when needed, and according to suggested guidelines.
Dr Muchahary said, Flu-like respiratory Illness Transmission, or FLiRT, is a serious public health concern that is more likely to affect specific groups of people. Due to their weaker defences against infections, those with weakened immune systemssuch as those receiving chemotherapy or suffering from autoimmune disordersare more vulnerable. Elderly people are also more vulnerable, particularly those over 65, since ageing frequently results in immune system deterioration and a higher chance of underlying medical disorders. Furthermore, people with long-term illnesses, including diabetes, heart disease, or lung disorders, are more susceptible to serious side effects from FLiRT. Targeted interventions are crucial to addressing these discrepancies; these include community outreach initiatives, access to healthcare services, and extensive immunisation campaigns to make sure that disadvantaged communities receive the assistance needed.
Understanding the variant in the context of the spectrum of symptoms exhibited by FLiRT is similar to that of other strains of SARS-CoV-2, ranging from respiratory to systemic. To effectively traverse the continued issues provided by COVID-19 variations, healthcare providers, public health authorities, and the general public must recognise these prevalent symptoms and their implications for diagnosis and management. Stakeholders can help with effective response activities and lessen the impact of FLiRT and other developing variations on global health by continuing to be watchful, knowledgeable, and proactive.
May 9, 2024 Bird fluH5N1 avian flu virushas been spreading among dairy cows across the U.S. So far, theres only one known case of the virus possibly passing from a cow to a human, but experts are concerned there may be more cases we dont know about, and about the potential for further spread. Bill Hanage, associate professor of epidemiology at Harvard T.H. Chan School of Public Health, doesnt think that a bird flu pandemic is imminent at least not yet.
Q: Some experts are saying that the spread of bird flu in cows may be much broader than it appears. Why would that be? Why wouldnt we have a handle on the spread?
A: Outbreaks at the interface of animal and human health are hard to study in the U.S. because theyre covered by different jurisdictions. The USDA [U.S. Department of Agriculture] oversees farm issues and its focus is on agriculture. While the USDA does have an emergency response team dedicated to influenza, farmers may have concerns about people coming onto their property to collect samples from livestock or workers, and some of those workers may not have documented immigration status. But those workers are at risk of infection, as shown by a case of human infection that occurred in early April. Samples from animals at the relevant farm were reportedly not available for testing.
If we cant collect samples directly from cattle, we have to look at something like milk, and we have indeed found that a lot of tested milk samples contain genetic traces of the bird flu. But that does not tell us how many cows might be infected. Its not at all clear because the milk we are testing is not from just one cow but many, and so we have no idea how many of them were contributing to the signal. All we can say is that it is certainly not a small number given how many samples are coming back positive, but beyond that we just dont know exactly how many infected cows there are, where they are, or how many may have been very mildly infected and not detected.
One of the problems is the way public health has been politicized following the COVID pandemic. But the virus doesnt care what side youre onit only cares if you have the appropriate receptors so that it can get into your cells, and from there into somebody else.
Q: What sort of information would help scientists figure out the extent of bird flu spread among cows?
A: Much more sampling, from cattle with and without symptoms, as well as from workers who have contact with them. Ideally this would include antibody tests to determine whether they have been infected and recovered in the past. Transparency is really important when it comes to public health.
While genomes from the outbreak have been made available by the USDAalthough they did not do so with alacritythey were initially criticized for lacking essential content such as when and where the samples were collected, which is really important to start making sense of the spread. It now looks like there was a single introduction from birds into dairy cattle in Texas, which was then disseminated to other states via movement of asymptomatic cattle. We can also see that the genetic variation is consistent with rapid exponential growth. The USDA has recently required dairy cattle to test negative for the virus before being transported across state lines, which is a welcome step. Although at present testing is only required for dairy cows that are lactating, so it is easy to see how the virus could slip through the net. In any case, this may be a case of shutting the barn door after the cow has bolted.
Q: As of now, theres just one known instance in which a cow appears to have infected a human with bird flua case of conjunctivitis in a dairy farm worker from Texas. How could the virus start spreading more in humans?
A: It could adapt to bind to the receptors that are found in our upper airways, which would help respiratory spread. Right now it sticks to receptors deeper in the lung, which is one reason why infections there, when they occur, are so nasty. Cows dont typically get respiratory infections with the sort of flu viruses that transmit among humans because they dont have the right receptors in the right place. Instead, milk production seems to be key for transmission in the current outbreak. But pigs can be infected by all sorts of different flu viruses that are also capable of respiratory spread among humans. Previously weve seen pandemics arise from whats called reassortment, in which a pig gets infected with two different viruses, and the genetic material gets mixed up in the pig, and what comes out is a new virus with new properties. Thats one way that the virus might make an evolutionary leap and start to transmit among humans, so we should keep a close eye on pigs to see whether the cattle outbreak is seeding infections into them.
Q: If the virus does start spreading in humans, could that cause another pandemic?
A: It certainly could but it would depend on the state of our immunity to whichever virus gets lucky and exactly how transmissible it is. As it happens, the infections that have been occurring in Texas seem to be a type that is a good match for some existing components of a vaccine that we would be able to start making.
On the other hand, vaccines dont appear from thin air; they take time to produce. One of the major ways that we make them involves hens eggs. Dont forget, were dealing with an avian flu that has affected chickensoutbreaks in poultry farms in two states have recently been detected. As a result of bird flu outbreaks, eggs have been in short supply at some points in the last few years, and that could make ramping up production of a vaccine a more difficult task. We wont be able to do it overnight. It would take months at the very least.
Another tool we have is the antiviral drug Tamiflu. But to be effective, it needs to be given quite early on in the infection. So we also need to have tests ready.
Q: So if the virus did start to spread quickly, how prepared are we?
A: What disturbs me most about this is that theres no serious discussion about what we would do if the you-know-what hits the fan. If we were to see any evidence of human-to-human transmission without links to livestock, that would be immensely concerning. If we see larger numbers of such infections in clusters, or even more than one cluster, it would be time to start making vaccinetime to pull out all the stops. The reason is that, in the early stages of infectious disease outbreaks, youre always playing catchup. Youre racing behind the virus, seeing where it has been, not where it is. You can bet that if we are seeing cases, there are others that were not seeing.
Q: Genetic material from H5N1 has been found in pasteurized milk, and the FDA has been testing ground beef. Should we be concerned about risk to humans?
A: Pasteurization inactivates the virus, so pasteurized milk is safe. And right now tests on ground beef have come back negative. We should remember that these tests are exquisitely sensitive, and do not reflect live virus. However, I would avoid unpasteurized or raw milk products. There have been several infections in cats that almost certainly were exposed by drinking milk on the farms in question.
Q: Whats the bottom line? How worried should we be about an outbreak?
A: If it was easy for this virus to spread among humans, it would have likely done it already. Having said that, this strain is far better than most bird flu at infecting all sorts of different mammalsthere have been outbreaks in seals, farmed mink, and now cattle. We have seen sporadic spillover infections in skunk and racoons among others, as well as the single human case identified so far. All of that indicates that this is a generalist virus [one that can infect and evolve in multiple species]and those are the ones you want to keep an eye on.
Even though I dont think theres reason to believe a pandemic is imminent right now, we will have another flu pandemic at some point, and we should be ready for it. Not having a plan is just beyond stupid. Dont panic, do prepare.
Karen Feldscher
Photo: iStock/Sabrina Gordon
It emerged as a powerful tool for public health officers during the COVID-19 pandemic, when it was used to gauge the prevalence of coronavirus in communities across the nation.
But wastewater surveillance the testing of sewage for signs of pathogens such as SARS-CoV-2, poliovirus and mpox virus has yet to be employed in the tracking of H5N1 bird flu virus.
Now, as officials attempt to determine the extent of bird flu outbreaks among dairy herds, some experts are urging that wastewater surveillance begin immediately. Others are faulting the U.S. Centers for Disease Control and Prevention for reportedly discouraging its use.
It has been consistently demonstrated that wastewater surveillance only enhances traditional surveillance, and often outperforms it when it comes to early/timely outbreak or surge detection, said Denis Nash, distinguished professor of epidemiology and executive director of City University of New Yorks Institute for Implementation Science in Population Health.
In this case, since traditional surveillance is not really systematically occurring, and wastewater surveillance is relatively low-cost and easy to implement, it makes a lot of sense to me to go ahead and deploy it strategically, said Nash, whose team developed New York Citys community-based wastewater surveillance for SARS-CoV-2.
That has not been the view of the CDC, however.
Recently, Marc Johnson, a professor of molecular microbiology and immunology at the University of Missouri, said he was told by the agency not to use a virus assay hed created for the purpose of tracking H5N1 outbreaks. The reason? Johnson said officials told him it would just add to the confusion.
Johnson said that if the assay had been in widespread use earlier this year, the spread of bird flu through the nations dairy herds could conceivably have been stopped, or at least slowed down.
I always think the more information we have, the better, he said.
However, he said he did understand the governments rationale.
Public health does not like ambiguous information, he said. You get a positive, you dont know if thats from a cow or a bird. Or maybe from milk poured down the drain.
The CDC did not respond to questions from The Times.
Concern over the virus escalated in March, when federal officials announced the discovery of avian flu in a Texas dairy herd. Over the next few weeks, reports of the virus in other states began to pop up. It also showed up in barn cats that drank raw milk, and in one dairy worker.
H5N1 bird flu has now been detected in 36 herds across nine states, and health and U.S. Department of Agriculture officials are scrambling to determine its reach. They believe the virus was introduced by a wild bird either via contact or feed at a Texas farm in December, giving the virus months to travel to other herds and animals.
The virus was also found in one of five grocery-shelf milk samples tested by federal researchers. Those samples showed the virus had been inactivated by pasteurization, reducing the health threat to people.
In California, where the virus has yet to be detected in dairy cows, wildlife officials are keeping a wary eye on migrating wild bird populations as well as domestic poultry and farm animals.
Eric Topol, a professor of molecular medicine at Scripps Research Institute in La Jolla, said the CDC is off base to say wastewater surveillance would cause confusion.
If anything, we need to track the spread of the virus and its evolution, which isnt getting done well by USDA and CDC, he said.
Michael Payne, a dairy educator and researcher at the University of Californias School of Veterinary Medicine, agreed with that sentiment. Although he was not familiar with the assay Johnson devised, he said an accurate test would be valuable.
Such a wastewater assay could be a useful tool, even given the uncertainty of exactly where the virus was coming from, he said. There is a growing body of literature that is using PCR testing in wastewater to measure pathogens of public health interest.
Nash, of CUNY, said hed advocate for a strategic deployment of community-based and facility-based wastewater surveillance.
He said testing wastewater at hospitals and health clinics would provide clear signals if an outbreak were to occur. Starting testing now, when a baseline for other confusing elements such as contaminated milk and bird droppings could be established, would help quell that noise.
He said that in the current situation, we need reliable early warning because if community spread did happen, every additional day of notice would matter a great deal in terms of potential lives saved.
Just when you stopped regularly hearing about COVID-19 in the news, another infectious disease began to dominate headlines this spring: bird flu.
The good news isfor now, at leastpublic health experts dont see this latest bout of avian influenza evolving into the likes of the coronavirus pandemic. But given the disease has spread to poultry in 48 states, dairy cows in nine, and two people in Texas and Colorado, you may be worried about its potential impact on your health.
Fortune spoke with a trio of epidemiologists, who below answer critical public health questions about bird flu.
The type of bird flu thats currently circulating is a highly pathogenic avian influenza (HPAI)a disease that can seriously sicken wild and domestic birds, posing a major threat to the poultry industry and thereby the global economy, according to the U.S. Department of Agriculture (USDA). The other kind, low pathogenicity avian influenza, causes mild infection in wild fowl but can turn into HPAI in poultry.
Influenza viruses are divided into four types, A, B, C, and D, explains Edwin Michael, PhD, an epidemiologist at the University of South Florida College of Public Health. What we think of as the seasonal flu in humans is caused by types A and B. Bird flu falls under the umbrella of influenza A viruses. The strain currently spreading in the U.S. is H5N1, an HPAI named for proteins on the viruss surface.
It can spread very quickly through the bird populationwild birds. That can spread it all across the world, Michael tells Fortune. From the bird, the virus is shed in mucus, saliva, feces, and then that can go and get into domestic poultry.
When HPAI strains reach domestic poultry, they can kill entire flocks within days, the USDA says. Birds with HPAI infection may show a slew of symptoms including diarrhea, lack of energy and appetite, and a drop in egg production. Because HPAI cant be treated, poultry depopulation is the sole solution.
Such culling can be effective in curtailing the spread in birds crucial to U.S. agriculture and food production, says Dr. William Schaffner, a professor in the Division of Infectious Diseases at Vanderbilt University Medical Center.
This particular bird flu virus, in its variants, has actually been around for a long timeover a decade, Schaffner tells Fortune. Its been gradually spreading but recently, somehow, for reasons that at least I dont understand, its spread around the world has become much more prominent and much more widespread.
H5N1 is a shapeshifter, so to speak, due to its segmented DNA, Michael explains.
For example, if a human gets infected with a bird flu and also carries a human influenza A virus, these two viruses can exchange genetic material. This is known as genetic shift, Michael says. That can form very new viruses [and] cause epidemics.
Flu pandemics are rare, though, occurring roughly three times a century, Michael says. Perhaps the most notable is the so-called Spanish flu of 19181919, when the Centers for Disease Control and Prevention (CDC) estimates an avian-like H1N1 virus killed 50 million, and possibly as many as 100 million, people worldwide.
You probably remember the swine flu pandemic of 2009, caused by a previously unknown H1N1 virus that contained swine, human, and avian genes. How did that happen? Because bird flu viruses dont always effectively spread among humans, they sometimes need help from other species to thrive, Schaffner explains.
The pigs respiratory tract is set up in such a way that it can accept bird flu infections andandinfections with a human virus, Schaffner says. You could think of the pig as a test tube into which goes a bird flu and a human flu, and if that happens simultaneously in the same pig, then those two viruses get together and can have the capacity to exchange genetic elements.
While the latest H5N1 strain isnt known to spread among humans, it has already spilled over to more than a dozen species of wild mammals, from black bears to a bottlenose dolphin. As recently as May 3, red foxes in New York and Michigan tested positive, according to the USDAs Animal and Plant Health Inspection Service (APHIS).
This bird flu virus is not relying on pigs but is mutating on its own to become a more effective infection in a variety of different mammalian species, Schaffner says. The one that has been in the news is dairy cattle, which surprised every virologist.
Government agencies have been monitoring the latest bird flu outbreaks since Jan. 12, 2022, when a Northern Shoveler duck in Hyde County, North Carolina, tested positive for a Eurasian strain of H5N1.
Among wild birds, the disease had spread throughout more than 1,100 counties as of May 8, 2024, infecting nearly 9,400 fowl.
The situation is worse in U.S. poultry. As of May 7, nearly 91 million birds, including commercial poultry and backyard flocks, had been infected. This encompasses more than 1,100 outbreaks in 522 counties across 48 states.
APHIS recorded the first poultry infection in a commercial turkey flock in Dubois County, Indiana, on Feb. 8, 2022.
Though H5N1 has been circulating nationwide in wild birds, domestic poultry, and mammals since 2022, you may have only been hearing about it recently because of its jump to dairy cattle. The first positive case was documented in Texas on March 25, 2024.
As of May 7, nearly 40 dairy cattle herds had been infected across nine states.
The logistics of modern industrial farming may be fueling the H5N1 spread to cattle, Michael says.
Look at the density of animals in those farmsthose are not natural settings, Michael tells Fortune. So as soon as you get [an infection], these things will spread very quickly among farm animals.
Michael adds, We have to shed a light on how farming is done. Thats the trade-off, you want cheap meat and all the rest of it, but then you farm animals in this way and youre opening the door up for other things.
The Food and Drug Administration (FDA) acknowledges the presence of bird flu in dairy cows is a novel and evolving situation. That said, no previous studies have been done on the effects of pasteurizationa sterilization measure that kills harmful bacteriaon HPAI in bovine milk. However, the FDA says existing research has informed its understanding and conclusion that milk consumption is safe.
The FDA and USDA are conducting a national commercial milk sampling study, which includes milk-derived baby formula. As of May 1, no HPAI had been detected in any formula products. While bird flu had shown up in milk, sour cream, and cottage cheese samples, pasteurization inactivated the virus.
There is no need to be concerned about milk, eggs, [and] chicken as sources of infection, Schaffner tells Fortune. Im out there drinking milk, and we had chicken last night for dinner.
Both Schaffner and the FDA urge the public to steer clear of raw, unpasteurized milk. The CDC recommends cooking eggs and poultry to an internal temperature of 165 degrees to kill bacteria and viruses, H5N1 included.
Simply put, dont panic, says Michael Osterholm, PhD, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
Theres no evidence yet at this point that this is an imminent risk to humans, Osterholm tells Fortune. Weve not seen it cross over to humans in a way that would support that its going to be the next pandemic virus.
On the other hand, a reassortant event, or continued mutations, could occur tomorrow.
Two humans have so far caught H5N1, according to the CDC. A person exposed to dairy cattle in Texas tested positive April 1, 2024, and a person in Colorado involved in culling poultry tested positive April 28, 2022. No human-to-human transmission has been confirmed, and the more recent patients only symptom was conjunctivitis, or pink eye.
We do have two, three receptor sites in our eyes, and so having a case of conjunctivitis would not be considered unusual, Osterholm says. There was no evidence of any kind of respiratory infection, which is the key piece for serious illness and then being able to transmit the virus.
The Texas case marks the first time a human has been infected with H5N1 through contact with a mammal, according to the World Health Organization (WHO). Even so, WHO considers the public health risk to the general population low. For farmworkers and other industry staff likely to be exposed to the virus, the risk is low to moderate.
Going forward, assuring the health and safety of agriculture workers is paramount to keeping H5N1 from spreading to the wider population, Michael says.
I dont think this one is going to be a major outbreak (in humans), Michael says. [But] the risk is always, always there because of the way we manage nature.
For more on the latest bird flu outbreak:
Highly Pathogenic Avian Influenza (HPAI) is a disease that is highly contagious and often deadly in poultry, caused by highly pathogenic avian influenza A (H5) and A (H7) viruses; it is also known as bird or avian flu. HPAI viruses can be transmitted by wild birds to domestic poultry and other bird and animal species. Although bird flu viruses do not normally infect humans, sporadic human infections have occurred. It is important to note that highly pathogenic refers to severe impact in birds, not necessarily in humans.
What's New|Previous Updates
Background (including: Review of Available Data, OngoingResearch, DataConsiderations,Precautions for Raw Milk, andConclusions)
Additional Resources
May 10, 2024
The FDA, alongside our federal and state partners, is continuing to take a stepwise approach to our scientific analysis of commercial milk safety during the first-of-its-kind detection of HPAI H5N1 in dairy cattle. While our initial assessment of the milk safety system continues to be affirmed by sampling and testing of retail dairy products, there remain a number of collective activities being undertaken to ensure the continued effectiveness of the federal-state milk safety system. The FDA will continue to follow a sound scientific process to inform the agencys public health decisions related to food safety.
Last week we announced preliminary results of a study of 297 retail dairy samples, which were all found to be negative for viable virus. The FDA is today announcing that all final egg inoculation tests associated with this retail sampling study have been completed and were also found to be negative for viable HPAI H5N1 virus. These confirmatory test results mark the completion of our laboratory research efforts related to these 297 retail dairy samples. Additional sampling and other surveillance activities will continue.
While our retail sampling test results to date are clear about the safety of the commercial milk supply and representative of real-world scenarios, additional scientific work is being undertaken to validate the criteria for pasteurization relative to the HPAI H5N1 virus and will include tests using pasteurization equipment typically used by milk processors. Today, wed like to share more about our additional research efforts.
The established pasteurization process set forth in federal regulation (21 CFR 1240.61) and the Pasteurized Milk Ordinance (PMO) provides specific temperature and time requirements for effective elimination of known pathogens in the milk supply. To further validate pasteurization effectiveness against this recently detected virus, the FDA previously noted it was testing samples of pooled raw milk routed for commercial processing to characterize potential virus levels that the pasteurization process must eliminate. Our pasteurization study is designed to better replicate real-world conditions to deliver the pasteurization treatment parameters set forth in the CFR and PMO, and to assess their effectiveness in inactivating HPAI H5N1 in bovine milk and other dairy products.
The results from this study will help further the FDAs understanding of pasteurization efficacy against anticipated concentrations of virus under real-world processing conditions. The pasteurization study is ongoing and we anticipate making preliminary results available in the near future.
Today, the agency is also announcing an additional $8 million is being made available to support its ongoing response activities to ensure the safety of the commercial milk supply. This funding will support the agencys ability to validate pasteurization criteria, conduct surveillance at different points in the milk production system, bolster laboratory capacity and provide needed resources to train staff on biosecurity procedures.
Additionally, these funds will help support HPAI H5N1 activities in partnership with state co-regulatory partners, who administer state programs as part of the federal/state milk safety system. It may also allow the FDA to partner with universities on critical research questions.
To date, the totality of evidence including studies on the effectiveness of pasteurization against multiple pathogens, recent studies on the effectiveness of pasteurization of HPAI H5N1 in eggs at lower temperatures than generally used in dairy products, negative retail sample results to date, and real-world evidence from the last 100 years of the PMO continues to indicate that the commercial milk supply is safe.
At the same time, the FDA also continues to advise against the consumption of raw milk (milk that has not been pasteurized). The FDA and CDC have long standing information regarding the increased risk of foodborne illness associated with numerous pathogens that may be present in raw milk. This increased risk exists for both humans and other animals that might drink raw milk. Additional guidance on raw milk and milk handling can be found on our website.
We are committed to continuing to initiate, support, and collaborate on research and surveillance of milk production, processing, and pasteurization to further our public health goals.
This additional preliminary testing did not detect any live, infectious virus.
In addition to preliminary results released late last week on an initial set of 96 retail milk samples, these results reaffirm our assessment that the commercial milk supply is safe.
To ensure the safety of milk-derived products for our youngest populations, the FDA also tested samples of retail powdered infant formula and powdered milk products marketed as toddler formula. All qPCR results of formula testing were negative, indicating no detection of HPAI H5N1 viral fragments or virus in powdered formula products so no further testing was required for these samples. The FDA is continuing to identify additional products that may be tested.
The FDA is also continuing to test samples of pooled raw milk that has been routed to pasteurization and processing for commercial use. This will be used as a basis to characterize potential virus levels that pasteurization may encounter and will be used to inform studies to further validate pasteurization.
As this situation evolves, the FDA will continue to consider all ongoing scientific research related to the effectiveness of pasteurization for HPAI in bovine milk. We are also committed to continued surveillance of milk production, processing and pasteurization to help ensure the safety of the milk supply. Our state partners are integral to this process, and we are working with them on a continual basis. We will also continue working with our state co-regulators on managing this emerging disease.
The FDA continues to advise strongly against the consumption of raw milk and recommends that industry does not manufacture or sell raw milk or raw milk products.
This additional testing did not detect any live, infectious virus. These results reaffirm our assessment that the commercial milk supply is safe.
In addition, several samples of retail powdered infant formula were tested, as well as powdered milk products marketed as toddler formula. All qPCR results of formula testing were negative, indicating no detection of viral fragments or virus in powdered formula products.
The FDA is further assessing retail samples from its study of 297 samples of retail dairy products from 38 states. All samples with a PCR positive result are going through egg inoculation tests, a gold-standard for determining if infectious virus is present. These important efforts are ongoing, and we are committed to sharing additional testing results as soon as possible. Subsequent results will help us to further review our assessment that pasteurization is effective against this virus and the commercial milk supply is safe.
Epidemiological signals from our CDC partners continue to show no uptick of human cases of flu and no cases of HPAI H5N1, specifically, beyond the one known case related to direct contact with infected cattle.
Today, the FDA received some initial results from its nationally representative commercial milk sampling study. The agency continues to analyze this information; however, the initial results show about 1 in 5 of the retail samples tested are quantitative polymerase chain reaction (qPCR)-positive for HPAI viral fragments, with a greater proportion of positive results coming from milk in areas with infected herds. As previously noted and outlined in our summary below, qPCR-positive results do not necessarily represent actual virus that may be a risk to consumers. Additional testing is required to determine whether intact pathogen is still present and if it remains infectious, which would help inform a determination of whether there is any risk of illness associated with consuming the product. The FDA is further assessing any positive findings through egg inoculation tests, a gold-standard for determining if infectious virus is present. Early work by NIH-funded investigators indicates an absence of infectious virus in their studies of retail milk. To date, the retail milk studies have shown no results that would change our assessment that the commercial milk supply is safe. Epidemiological signals from our CDC partners continue to show no uptick of human cases of flu and no cases of HPAI H5N1, specifically, beyond the one known case related to direct contact with infected cattle. These important efforts are ongoing, and we are committed to sharing results from both the qPCR and egg inoculation tests as soon as possible.
The U.S. Department of Agriculture (USDA), the U.S. Food and Drug Administration (FDA), and the Centers for Disease Control and Prevention (CDC), along with state partners, continue to investigate an outbreak of highly pathogenic avian influenza (HPAI) virus impacting dairy cows in multiple states. Infection with the virus is causing decreased lactation, low appetite, and other symptoms in affected cattle.
The FDA and USDA have indicated that based on the information currently available, our commercial milk supply is safe because of these two reasons:
1) the pasteurization process and
2) the diversion or destruction of milk from sick cows.
The pasteurization process has served public health well for more than 100 years. Pasteurization is a process that kills harmful bacteria and viruses by heating milk to a specific temperature for a set period of time to make milk safer. Even if virus is detected in raw milk, pasteurization is generally expected to eliminate pathogens to a level that does not pose a risk to consumer health. However, pasteurization is different than complete sterilization; sterilization extends shelf life but is not required to ensure milk safety. While milk is pasteurized, not sterilized, this process has helped ensure the health of the American public for more than 100 years by inactivating infectious agents.
Nearly all (99%) of the commercial milk supply that is produced on dairy farms in the U.S. comes from farms that participate in the Grade A milk program and follow the Pasteurized Milk Ordinance (PMO), which includes controls that help ensure the safety of dairy products. Pasteurization and diversion or destruction of milk from sick cows are two important measures that are part of the federal-state milk safety system.
There are a number of collective activities being undertaken to ensure the continued effectiveness of the federal-state milk safety system. In addition to these specific research activities, the FDA is collaborating closely with CDC's food safety group, as well as its surveillance team thats monitoring emergency department data and flu testing data for any unusual trends in flu-like illness, flu, or conjunctivitis. To date, surveillance systems do not show any unusual trends or activity.
As noted by USDA and some press reports from the World Health Organization (WHO) and other sources, the presence of the virus has been detected in raw milk. Based on available information, pasteurization is likely to inactivate the virus, however the process is not expected to remove the presence of viral particles. Therefore, some of the samples collected have indicated the presence of HPAI using quantitative polymerase chain reaction (qPCR) testing.
During the course of the outbreak, the FDA has been evaluating milk from affected animals, in the processing system, and on the shelves. We are completing a large representative national sample, to better understand the extent of these findings. Because qPCR findings do not represent actual virus that may be a risk to consumers, the FDA is further assessing any positive findings through egg inoculation tests, a gold-standard for determining viable virus. To date, we have seen nothing that would change our assessment that the commercial milk supply is safe. Results from multiple studies will be made available in the next few days to weeks.
Sound science is critical to informing public health decisions like those made by the FDA related to food safety and we take this current situation and the safety of the milk supply very seriously. We recognize the importance of releasing further, actionable information.
Review of Available Data
Given that the detection of H5N1 in dairy cows is a novel and evolving situation, no studies on the effects of pasteurization on HPAI viruses (such as H5N1) in bovine milk have previously been completed although considerable scientific literature is available that has informed our current understanding.
The established pasteurization process set forth in the PMO provides specific times and temperature requirements [i] for effective pasteurization of known pathogens in the milk supply. Data from previous studies [ii, iii], that serve as the underpinnings of the FDAs current milk supply safety assessment show that pasteurization is very likely to effectively inactivate heat-sensitive viruses, like H5N1, in milk from cows and other species. Additionally, data [iv, v, vi] shows thermal inactivation of HPAI (H5N1) has been successful during the pasteurization process for eggs, which occurs at lower temperatures than what is used for milk.
Ongoing Research
U.S. government partners have been working with deliberate speed on a wide range of studies looking at milk along all stages of production -- on the farm, during processing and on shelves -- using well- established methodologies used previously to confirm pasteurization effectiveness for known pathogens.
This work is a top priority, and we are proceeding in an efficient, methodical, and scientific fashion to ensure the continued effectiveness and safety of the federal-state milk safety system.
Laboratory benchtop tests are the first part of this ongoing work. This includes testing laboratory generated samples inoculated with high levels of a recently isolated and closely related avian flu virus and samples of raw, unpasteurized milk directly from cows in affected herds with and without symptoms to understand how, and at what levels, heat treatment (pasteurization) inactivates the virus.
While this information is important, this testing alone cannot provide a complete picture as these samples are not representative of what we would expect to see in the real-world from milk routed to pasteurization and processing for commercial use.
In addition to lab testing, a critical step in the scientific confirmation process includes testing of milk that is representative of real-world scenarios in which milk is typically pooled in large amounts from numerous healthy cows from numerous farms before pasteurizing and processing.
Work is underway to test samples of milk in systems that represent current industry practices using the range of temperature and time combinations that are used in pasteurization processes.
Additional analysis is underway of milk on store shelves across the country in addition to work to evaluate any potential differentiation for various types of dairy products (e.g., whole milk, cream).
We are aware that universities or other entities are conducting work in this area, particularly universities and consortia supported by the National Institutes of Health. We look forward to reviewing all results generated from various scientific studies, testing methods and the product(s) used as we continue assessing all the data and information available. We are committed to collaborating with the broad community to come to sound scientific conclusions regarding this situation -- which its important to understand takes time.
Data Considerations
Multiple tests are used to assess the safety of food items. Understanding how and why different methodologies are used and work, as well as how results fit into the larger picture, is critical to interpret any findings.
Precautions for Raw Milk
The FDA has a long-standing recommendation to consumers not to consume raw milk (milk that has not been pasteurized). Because of the limited information available about the possible transmission of H5N1 virus via raw milk, the FDA continues to recommend that industry does not manufacture or sell raw milk or raw milk products, including raw milk cheese, made with milk from cows showing symptoms of illness, including those infected with avian influenza viruses or exposed to those infected with avian influenza viruses.
Importantly, the FDA has also recommended producers take precautions when discarding milk from affected cows so that the discarded milk does not become a source of further spread. Producers should consult with their state regulatory authorities for specific recommendations or requirements; however, such precautions should include heat treatment, pasteurization or its equivalent, of discarded milk prior to dumping in lagoons or application of waste solids and ensuring biosecurity around lagoons (e.g., ensuring that animals and birds do not have access to lagoons). Any raw milk or raw milk products from exposed cattle that are fed to calves (or to other animals, such as farm cats) should be heat treated or pasteurized.
Conclusion
The PMO and pasteurization continue to provide important measures to assure milk safety. Given this is the first time we have seen this virus affect cows, these are the first studies that have been initiated to look at the effectiveness of pasteurization on HPAI viruses such as H5N1 in bovine milk.
As previously noted, the FDA is collaborating closely with CDC's food safety group, as well as its surveillance team thats monitoring emergency department data and flu testing data for any unusual trends in flu-like illness, flu, or conjunctivitis. To date, surveillance systems do not show any unusual trends or activity. Only one associated human case from a person exposed to infected cows has been linked with this outbreak in dairy cows to date and CDC says risk to the general public remains low.
The FDA and USDA are working closely to collect and evaluate additional data and information specific to H5N1 in dairy cattle and to support state counterparts as this emerging disease in dairy cattle is managed. These important efforts are ongoing, and we are committed to sharing results as soon as possible. In the meantime, the FDA and USDA continue to indicate that based on the information we currently have, our commercial milk supply is safe.
i. 21 CFR part 131 -- milk and cream. (n.d.). https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-131
ii. Pitino, M. A., OConnor, D. L., McGeer, A. J., & Unger, S. (2021). The impact of thermal pasteurization on viral load and detectable live viruses in human milk and other matrices: a rapid review. Applied Physiology Nutrition and Metabolism, 46(1), 1026. https://doi.org/10.1139/apnm-2020-0388
iii. Jay, J. M., Loessner, M. J., Golden, D. A., & Keller, H. B. (2005). Food Protection with High Temperatures. In Modern Food Microbiology (pp. 415441). https://link.springer.com/chapter/10.1007/0-387-23413-6_17
iv. Chmielewski, R. A., Beck, J. R., & Swayne, D. E. (2011). Thermal inactivation of avian influenza virus and Newcastle disease virus in a fat-free egg product. Journal of Food Protection, 74(7), 11611169. https://doi.org/10.4315/0362-028x.jfp-10-415 https://doi.org/10.4315/0362-028x.jfp-10-415
v. Chmielewski, R. A., Beck, J. R., & Swayne, D. E. (2013). Evaluation of the U.S. Department of Agricultures egg pasteurization processes on the inactivation of high-pathogenicity avian influenza virus and velogenic Newcastle disease virus in processed egg products. Journal of Food Protection, 76(4), 640645. https://doi.org/10.4315/0362-028x.jfp-12-369
vi. Chmielewski, R. A., Beck, J. R., Juneja, V. K., & Swayne, D. E. (2013). Inactivation of low pathogenicity notifiable avian influenza virus and lentogenic Newcastle disease virus following pasteurization in liquid egg products. Lebensmittel-Wissenschaft Und Technologie [Food Science and Technology], 52(1), 2730. https://doi.org/10.1016/j.lwt.2013.01.002
The bird flu virus, which was first reported in US poultry farms in 14 states in early 2022, has spread to cows and two humans in the first-ever cases of bird flu in humans in the United States. The same subtype of bird flu is also spreading in other countries, in what experts are calling a global pandemic for animals.
US public health officials have been monitoring dairy cow herds, as well as beef and milk products around the country since the first outbreak in cows was reported in March. So far, the US is the only country to have reported bird flu in cattle, but there are fears that it could pose a serious threat to humans, too.
In April, a Texas farm worker contracted the virus in what is believed to be the first-ever transmission of the virus from a mammal in this case, cattle to a human. Thankfully, he suffered only mild conjunctivitis an infection in the eye and has since made a full recovery. The USs first-ever bird flu case in a human was reported in 2022 when a poultry farm worker in Colorado was exposed to infected chicken. He reported only fatigue as the main symptom.
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However, bird flu can be extremely dangerous for humans. Since the virus also known as Avian Influenza was first detected nearly three decades ago in China, some 860 people have been infected by birds in 23 countries, including China, Egypt, Vietnam and Turkey, according to the World Health Organization (WHO). Of those, 463 people died from the virus, giving a huge 52 percent death rate.
So far, the Centres for Disease Control and Prevention (CDC) has detected the virus in more than 200 cows, 9,000 wild birds and some 90 million chickens across the US.
On Friday last week, Canada began implementing stricter import checks for US cattle, following similar measures in Colombia.
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So how is bird flu spreading, and could it become a more serious threat to humans?
Bird flu is a viral infection that primarily affects birds. Some strains of bird flu can, however, also be infectious to other animals, including humans.
Bird flu belongs to the Influenza A group, one of four types of influenza, and the only one known to cause flu pandemics.
There are also subtypes of avian influenza. Three of these H5N1, H5N6 and H7N9 have been found to cause illness in humans as well. While the letters in the names of these subtypes refer to a combination of proteins found in bird flu, the numbers indicate the subtype.
The first and best-known subtype of bird flu is H5N1, which was first identified in domestic geese in the Guangdong province of southern China in 1996. This is the subtype of bird flu which is currently affecting birds and cattle in the US.
In birds, the virus is likely to cause severe disease and death. Cows, particularly older ones, have displayed symptoms such as reduced appetite and lactation when infected.
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This particular strain of the H5N1 virus has been causing a global pandemic for animals the term is an epizootic disease and it has affected a lot of domestic poultry production, said Meghan Davis, associate professor at the Johns Hopkins Bloomberg School of Public Health and trained dairy veterinarian.
Since late March, H5N1 has been reported in around 200 animals in 36 dairy cattle herds in the US states of Colorado, South Dakota, Kansas, Michigan, North Carolina, Idaho, Texas, Ohio and New Mexico.
Some experts suspect that the outbreak may have begun to spread to cows before March even as early as late 2023 but was not reported.
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What we dont know is just how widespread this might be, said Davis. This is something where we need lots of surveillance, lots of eyes on this, lots of different ways of looking at the challenge.
Although there have been no confirmed cases of bird flu in cows beyond US borders so far, the World Health Organization (WHO) has warned that there is a risk of it spreading internationally through the movement of migratory birds.
With the virus carried around the world by migratory birds, certainly there is a risk for cows in other countries to be getting infected, said Wenqing Zhang, head of WHOs Global Influenza Programme, at a news briefing in Geneva in late April.
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H5N1 is described by the CDC as highly pathogenic, meaning it is strongly able to cause disease, in birds. But it has also proved to be deadly to humans in past cases. Only 860 people around the world have contracted the virus since it was first discovered in 1996, but more than half of those have died from it, according to the WHO.
Farm workers or others in direct contact with infected animals are most at risk. Beyond that, humans are unlikely to be able to transmit the virus to each other, although there was one suspected case of human-to-human transmission in Indonesia in 2006.
In humans, bird flu can cause a range of symptoms within two to eight days after infection. This ranges from fever, cough, sore throat and muscle aches, to more severe effects such as pneumonia and organ failure.
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There is no vaccine for bird flu in humans. Infected people are typically prescribed antiviral medication such as oseltamivir or zanamivir to manage the symptoms. Health authorities including the CDC recommend administering such drugs as soon as symptoms begin.
In most parts of the world, farmers cull animals which have been exposed to an outbreak of a deadly virus such as bird flu. Early in April, for example, a poultry farm in Texas destroyed 1.5 million chickens to curtail the spread of bird flu.
So far, there have been no reports of cattle being culled. This is because bird flu has so far not been as deadly in cows as it has in chickens and turkeys, said Andrew Stevens, assistant professor of agricultural and applied economics at the University of Wisconsin-Madison.
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In this setting, culling would be an extreme and costly step to prevent further spread of the disease. This is especially true because we dont yet have as good a sense of how contagious the bird flu virus is between cattle, he said.
Bird flu can be spread by wild birds and waterfowl such as ducks and geese through their droppings or secretions such as saliva.
When poultry or other animals scavenge environments which have been contaminated or have come into contact with infected birds, they can catch the virus too. Infected wild birds may also be present on farms and come into contact with water or feed that cows consume, although researchers are still studying such potential modes of transmission, said Davis.
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In cattle, it is still not fully understood how the virus passes from one cow to another, but traces of the virus in milk suggest a heavy viral load can often be found in the mammary glands. Higher viral load in milk compared with respiratory tracts of cows may also point to the routes of exposure of the virus.
Scientists suspect, therefore, that the virus spreads when cows are milked, as equipment may become infected or the virus may become aerosolised suspended in the air during cleaning.
Humans who have close or prolonged contact with farm animals or wild birds can become infected when the virus enters their system via the eyes or mouth, or when droplets or small aerosol particles are inhaled via the nose.
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Since April, the US Food and Drug Administration (FDA) has tested 297 milk products, including milk, cottage cheese and sour cream. Traces of the virus were found in 20 percent of an initial 96 samples but additional testing has confirmed that pasteurisation a heating process used by farmers to screen out harmful pathogens and bacteria from farm products kills the virus, removing the danger for consumers.
Experts and public health authorities including the CDC strongly advise people to only consume pasteurised dairy products, not just because of avian flu but also to avoid bacterial infections such as salmonella and brucella.
Beef samples tested by the US Department of Agriculture (USDA) have so far tested negative for bird flu, but official advice from the FDA remains against consuming raw beef.
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There is a growing movement against food regulation, seen by some in Western countries such as the US as a symbol of freedom. In 2015, for example, Wyoming passed the Food Freedom Act which allows farmers to sell raw milk and other farm goods directly to customers.
Australia, the only country apart from Canada with a blanket ban on raw milk sales, also has a growing Raw Milk Movement which advocates for regulated distribution of unpasteurised products. Such regulations would include hygienic production and packaging of the milk, as well as testing for active harmful pathogens.
While 30 US states allow sales of raw milk, federal law prohibits the distribution of unpasteurised milk across state lines. Additionally, milk from sick cows must be discarded completely under federal law. In cases where raw milk has been packaged before cows are found to be ill, however, products with traces of the virus could still make it to store shelves.
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Although such a study has not been conducted on humans due to research ethics, US studies of cats which consumed raw milk infected with H5N1 showed that the cats became sick or even died as a result.
Experts and public health authorities such as the CDC say they have been studying bird flu for decades now, and that the COVID-19 pandemic has led to positive shifts in terms of preparing for outbreaks.
Regulatory authorities are also stepping up surveillance of viruses. In late April, the USDA began to require all dairy cattle moving between states to be tested for bird flu.
However, testing at farms within state boundaries is still only done on a voluntary basis, which may not be enough to curb the spread of the virus, said Davis.
What I would like to see happen is a switch from what we would consider to be more passive surveillance where we are waiting on farmers and workers to tell us that theyre having a problem, to a more active surveillance where were really trying to understand the scope of the problem, she said.
One way to do this is through antibody serology testing, she said, whereby samples of blood or saliva are taken from a human and tested to detect whether their immune system has been exposed to the virus recently.
Another form of testing is polymerase chain reaction (PCR) testing, which typically uses more invasive nasal swabs to determine if a person is currently infected and may not be best suited for those who are asymptomatic or have not had very high exposure to a virus, said Davis.
Rural populations in the US may especially be at a disadvantage during the outbreak, as they can lack access to healthcare services and personal protective equipment, she added. Medical centres may be far away and these populations may be unable to afford services.And if they [farmers] are not interested in having cows tested, then would the workforce even have the opportunity to get tested? Thats unclear, she said.
In late April, Colombia became the first country to limit trade with the US because of bird flu in cows. It has restricted imports of beef and beef products from states where cows have tested positive for the virus.
Mexico, a major market for US beef and dairy products, has also increased surveillance of cattle entering the country for any sign of respiratory distress, the agriculture ministry said.
On Friday last week, the Canadian Food Inspection Agency also tightened import controls relating to US cattle, introducing a requirement for exporters to provide negative bird flu test results for lactating dairy cattle as well as mandatory testing of retail milk to check for traces of the virus.
Stevens said such measures are important for the long-term sustainability of supply chains. Although increasing import checks of cattle and dairy products from the US may slightly increase the relative costs of US exports, these costs are small relative to the potential impacts of an import ban or moratorium.
The federal government Friday unveiled a major package of financial incentives to dairy farm owners up to $28,000 per farm over the next four months to encourage broader testing of cattle and expanded security measures to control a growing outbreak of the bird flu virus in cows.
The $98 million in incentives from the Department of Agriculture, available only to farms with infected herds, is being offered as federal officials grapple with critical questions over how the virus has been spreading among dairy herds since the H5N1 bird flu was first detected in dairy cows in late March. Federal officials are trying to determine the risks for human exposure and how long livestock shed the virus in their milk once they have recovered from an infection.
The Biden administration said on Friday that it would compensate dairy farmers for cooperating with its efforts to limit the spread of the bird flu virus, part of a series of expansive measures aimed at containing an outbreak.
The payment system amounted to one of the most forceful actions taken so far by agriculture officials who have raced to keep up with the spread of the virus among dairy cows. Farm owners have been reluctant to allow state and federal officials access to cows and workers exposed to or infected by the virus, and are fearful of the financial consequences of infected herds and contaminated milk.
Under the so-called indemnity program, farms would receive up to $28,000 to protect workers and cover costs incurred treating and testing sick cows. Producers may also receive payments for lost milk production on farms with confirmed bird flu cases.
Farm workers who agree to participate in government-led studies will also be compensated for their time.
Were now moving into a phase of equipping producers to reduce the risk of wider spread, Tom Vilsack, the agriculture secretary, said at a news briefing on Friday, acknowledging the difficulties of reaching farmers.
The program was part of a broader federal push announced on Friday to increase spending on the bird flu response. The Centers for Disease Control and Prevention is planning to scale up testing capacity a blind spot early in the coronavirus pandemic and its assessment of bird flu vaccines, should they be needed.
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