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Which states have found bird flu in dairy cows? Why is measles coming back? What states are having a measles outbreak? When is respiratory virus season over?
Our guest is AMA's Vice President of Science, Medicine and Public Health, Andrea Garcia, JD, MPH. American Medical Association Chief Experience Officer Todd Unger hosts.
Unger: Hello, and welcome to the AMA Update video and podcast. Today we have our weekly look at the headlines with the AMA's Vice President of Science, Medicine, and Public Health, Andrea Garcia. I'm Todd Unger, AMA's chief experience officer. Welcome back, Andrea.
Garcia: Thanks, Todd. It's great to be here as always.
Unger: Well, let's begin where we left off last week, and that's with bird flu. Andrea, what updates do we have on that topic?
Garcia: Well, that virus is continuing to spread among cattle, but I think the good news is there have been no new reports of human infection here in the U.S. There was some news according to the CDC that Vietnam has reported its first human infection with a low pathogenic avian influenza virus, that's H9N2.
It's a different subtype of avian flu than the highly pathogenic avian flu that's most reported globally and that's causing the outbreaks in poultry and cattle here in the U.S. At this time, there is no indication that this human infection in Vietnam is causing person-to-person spread or poses a threat to U.S. public health.
Unger: Well, that's good news. On the other hand, you did mention increased spread here among cattle, and that's obviously a problem. What is that looking like?
Garcia: There was a report in Reuters that indicated North Carolina and South Dakota became the seventh and eighth states to identify avian flu in a dairy herd. And just as a reminder, when we talked last week, the USDA had reported infections across six states, so Texas, Kansas, Ohio, Michigan, Idaho and New Mexico.
So now we're seeing dairy farmers across the country going on the defensive to try and prevent further spread. Many are banning visitors and disinfecting vehicles coming onto their land. Some are even cutting down trees to discourage wild birds from landing, since that first case in Texas and Kansas appear to have originated with birds.
Many are increasing their safety and cleaning procedures. In that Reuters article, one dairy farmer described her farm as a gated community for cows, where only the most essential people are allowed to go since people can unintentionally contribute to that spread by carrying in contaminated bird droppings on their boots or on their vehicles. The good news is that, as we discussed last week, cows do seem to recover, whereas the disease is lethal in poultry.
Unger: I never thought I'd heard that term gated community for cattle, but I understand folks wanting to protect their herds, and that's a big problem. So we'll continue to pay attention to this. Has the increased spread change the risk at all to people?
Garcia: No. The CDC says that the risk for most people remains low. However, some dairy farmers are concerned about a potential drop in demand for milk and cheese due to fear. The USDA did report finding bird flu in some unpasteurized milk samples, but agricultural officials say that pasteurized milk is safe. Farmers are also isolating those infected cattle and dumping their milk.
Unger: All right, Andrea, thank you so much for the update there. Let's turn now to another disease that is back in the headlines and continues to be for the past several weeks, and that's the measles. Andrea, what's going on there?
Garcia: Well, two new cases, one in Las Vegas, the other in Los Angeles, have really put this disease back in the news. More measles cases have also been reported in Georgia and here in Illinois. Unfortunately, the cases in both Las Vegas and Los Angeles were found in people who visited popular tourist destinations that are often, as you know, filled with people. The one in LA reportedly visited Universal Studios and the Santa Monica Pier over Easter weekend. The one in Vegas reportedly visited the MGM Grand resort on the strip and then additional nearby locations.
So public health officials are warning that unvaccinated individuals who were at these reported locations during the designated dates and times may be at risk for developing measles within 21 days from that exposure date. Last Thursday, the CDC said that the rapid rise in measles cases in the first few months of 2024 threatens the U.S. elimination status. And that's a situation we haven't faced since 2019 when prolonged outbreaks posed a similar problem.
Unger: Well, Andrea, where exactly do we stand in terms of cases?
Garcia: Well, Todd, on Thursday, we saw the CDC release an analysis of measles activity. And that was from January 1 of 2020 to March 28 of 2024. That said that cases in that first quarter of 2024 have risen 17-fold compared to that mean first quarter average that we've seen from 2020 to 2023. As of the March 28 data cutoff for that analysis, we had seen 97 cases of measles reported to the CDC, and then as of April 11, we have a total of 121 measles cases reported by 18 jurisdictions. So that number is definitely continuing to increase.
Of those 121 cases, 86 were linked to seven outbreaks, including a large one here in Chicago where most of those 61 cases that have been identified have been linked to that outbreak at a migrant shelter. If we look at the measles cases this year, though, 47% have occurred in children younger than five. Young children also had that highest level of hospitalization, at about 65%. And of people infected, 82% were unvaccinated or had an unknown vaccination status.
Of the 20 outbreaks, which we know involves three or more cases that we've seen since 2020, so far seven of those have occurred in 2024. And for further context, in all of 2023, we had 58 cases. And we are only in April. So maintaining that measles elimination status, which we know helps reduce cases, deaths and costs, means that no outbreaks have persisted for 12 months or more in a setting where we know the surveillance system is working well.
Unger: So tell us a little bit more about this status. What do we need to do to help maintain the status?
Garcia: Well, CDC has said that really comes down to increasing MMR vaccination coverage, especially in those close-knit and under-vaccinated communities. And as a reminder, that vaccine is incredibly safe and effective. We know that two shots are about 97% effective at preventing measles. I think the other steps include encouraging vaccination before international travel and then rapidly investigating those suspected measles cases.
Most measles cases are still imported. However, of those, 61% in U.S. residents who were eligible for vaccination but were unvaccinated or had an unknown vaccination status. So the CDC is also reportedly seeing a shift this year in overseas regions where people were likely exposed.
So during that study period that we talked about earlier, the two most common WHR regions where we saw cases were from the Eastern Mediterranean or the Middle East and Africa, but six of the 2024 cases were reported to have originated in European and Southeast Asian regions. So that's a 50% increase from earlier in the study period.
So according to the CDC, along with under-vaccination here in the U.S. population, there's a global gap in measles vaccination that is also fueling this rise in cases. And if we look at those numbers more closely, first dose coverage declined from 86% in 2019 to 83% in 2022, leaving nearly 22 million children younger than one vulnerable to the virus.
Unger: Andrea, besides this huge, as you point out, global vaccination gap, is there anything else that is kind of fueling this now? Why is it happening?
Garcia: Well, in the U.S., some of it is driven, of course, by misinformation, which is causing parents to seek vaccine exemptions. Every year, that number of kids in kindergarten with measles vaccination is going down.
Years ago, a fraudulent study claimed there was a link between the vaccine and autism. Of course, that study was later debunked. And other studies have searched for a connection but failed to find one. So to be very clear, there's no connection between the MMR vaccine and autism. So here's where physicians and particularly pediatricians can play an important role in curbing that spread of misinformation by talking to parents, being very clear about the evidence and the very real dangers and potential long-term effects of measles.
According to the CDC, in the decades before the measles vaccine was available, 48,000 people were hospitalized per year. One thousand people developed dangerous brain inflammation, and 400 to 500 people died.
Unger: So big risks there, and we need to close that gap. The evidence is really clear and getting those vaccinations, if you haven't already, so critical. Andrea, we haven't talked about RSV, COVID, and the flu and the array of other viruses for a while. The weather does seem, of course, to be getting nicer, thank goodness, it is here in Chicago, and we're now well into spring. Are we kind of out of the woods with viruses for the moment?
Garcia: Well, it appears so. And according to a recent report in the Associated Press, which was sharing CDC data, the 2023, '24 respiratory virus season is slowing for all three viruses. Overall, respiratory illness activity is currently the highest in the central U.S. North Dakota is the only state that is experiencing high activity levels at the moment.
The CDC gauges this activity by tracking doctor visits that involve a patient showing flu-like symptoms. And for that week of April 5, those made up only about 2.76% of all visits. The other metric, as you know, we look at is the test positivity rate for each virus, which can help inform which viruses are the most prevalent. While results are delayed for the CDC data set, flu has had the highest test positivity rate since mid-December.
Hospitalizations, of course, give us that idea of severity associated with each virus. COVID is hospitalizing people at a rate of 2.21 per 100,000. That's the highest rate among the three viruses. However, hospitalization rates for all three viruses are declining. I think the key takeaway from all of this as well, activity levels are still elevated. We're seeing decreasing trends across each of these metrics, which do suggest that the season is waning.
Unger: All right. Well, why don't we finish up then with that piece of good news. Andrea, thanks so much for being here and keeping us informed. To all the folks out there listening, if you found this discussion valuable, you can support more programming like it by becoming an AMA member at ama-assn.org/join.
We'll be back soon with another AMA Update. In the meantime, you can find all our videos and podcasts at ama-assn.org/podcasts. Thanks for joining us today and please take care.
Disclaimer: The viewpoints expressed in this video are those of the participants and/or do not necessarily reflect the views and policies of the AMA.
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This year is not yet one-third over, yet measles cases in the United States areon track to be the worstsince a massive outbreak in 2019. At the same time, anti-vaccine activists are recklessly sowing doubts and encouraging vaccine hesitancy. Parents who leave their children unvaccinated are risking not only their health but also the well-being of those around them.
Measles isone of the most contagioushuman viruses more so than thecoronavirus and is spread through direct or airborne contact when an infected person breathes, coughs or sneezes. The virus can hang in the air for up to two hours after an infected person has left an area. It can cause serious complications, including pneumonia, encephalitis and death, especially in unvaccinated people. According to the Centers for Disease Control and Prevention,one person infected with measles can infect 9 out of 10 unvaccinated individualswith whom they come in close contact.
But measles can be prevented with the measles, mumps and rubella vaccine. Two doses are 97% effective. When 95% or more of a community is vaccinated, herd immunity protects the whole. Unfortunately, vaccination rates are falling. Theglobal vaccine coverage rateof the first dose, at 83%, and second dose, at 74%, are well under the 95% level.Vaccination coverage among U.S. kindergartnershas slipped from 95.2% during the 2019-2020 school year to 93.1% in the 2022-2023 school year, according to the CDC, leaving about 250,000 kindergartners at risk each year over the past three years.
The virus is slipping through the gaps. According to the World Health Organization, in 2022,37 countries experienced large or disruptive measles outbreakscompared with 22 countries in 2021. In the United States, there have beenseven outbreaks so far this year, with 121 cases in 18 jurisdictions. Most are children. Many of the outbreaks in the United States appear to have been triggered byinternational travelor contact with a traveler. Disturbingly, 82% of those infectedwere unvaccinatedor their status unknown. ...
The largest toll has been in Illinois, followed by Florida. But when an outbreak hit the Manatee Bay Elementary School in Broward County in early March, Floridas top public health official, state Surgeon General Joseph A. Ladapo,did not follow the standard recommendationthat parents of unvaccinated children keep them home for 21 days to avoid getting the disease. Instead,Dr. Ladapo said, Florida would be deferring to parents or guardians to make decisions about school attendance. This means allowing children without protection to go to school. Dr. Ladapos letter was an unnecessarily reckless act of pandering to an anti-vaccine movement with increasing political influence.
Vaccine hesitancy is being encouraged by activists who warn of government coercion, using social media to amplify irresponsible claims. An article published March 20 on the website of Robert F. Kennedy Jr.s Childrens Health Defense organization is headlined,Be Very Afraid? CDC, Big Media Drum Up Fear of Deadly Measles Outbreaks.The author, Alan Cassels, claims that the news media is advancing a a fear-mongering narrative, and adds, Those of us born before 1970 with personal experience pretty much all agree that measles is a big meh. We all had it ourselves and so did our brothers, sisters and school friends. We also had chicken pox and mumps and typically got a few days off school. The only side effect of those diseases was that my mom sighed heavily and called work to say she had to stay home to look after a kid with spots.
Today, he adds, Big media and government overhyping the nature of an illness, which history has shown us can be a precursor to some very bad public health policies such as mandatory vaccination programs and other coercive measures.
This is just wrong. TheCDC reportsthat, in the decade before the measles vaccine became available in 1963, the disease killed 400 to 500 people, hospitalized 48,000 and gave 1,000 people encephalitis in the United States every year and that was just among reported cases. The elimination of measles in the United States in 2000, driven by a safe and effective vaccine, was a major public health success. Though the elimination status still holds,the U.S. situation has deteriorated.The nation has been below 95% dose coverage for three consecutive years, and 12 states are below 90%. At the same time, the rest of the world must also strive to boostchildhood vaccination rates, which slid backward during the COVID-19 pandemic. According to the WHO, low-income countries with the highest risk of death from measles continue to have the lowest vaccination rates, only 66%.
The battle against measles requires a big not a meh effort.
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Scientists are calling on the international community to contain a worrying new mutated strain of mpox that has been discovered in a mining town in the Democratic Republic of Congo.
The virus is an offshoot of the deadly clade 1 mpox strain, but has evolved to become even better at spreading and evading tests than its predecessor.
Mpox, previously called monkeypox, is a rare infection that originated in west or central Africa. Although symptoms may be mild, the infection can cause unusual rashes and blisters, fevers, headaches, muscle ache, exhaustion and swollen lymph nodes.
In 2022, the virus spread to 110 countries, with the majority of cases reported among gay and bisexual men.
So far, 241 cases of the new strain have been suspected and 108 confirmed in Kamituga
STRINGER/AFP via Getty
The DRC is now caught in the grip of a much more deadlier form of clade 1, which kills up to 10 percent of people who get sick.
In the first quarter of 2024 alone, 3,576 people were infected and 264 were killed, according to the World Health Organization (WHO). Two thirds of cases and 85 percent of fatalities were among children.
The mutated strain is wreaking havoc in Kamituga a poor, densely populated gold mining town with a population of 242,000 residents that's located just 170 miles from the Rwandan border. So far, 241 cases of the new strain have been suspected and 108 confirmed.
It is believed to have made the jump from animals to humans somewhere between July and September 2023.
"Without intervention, this localised Kamituga outbreak harbors the potential to spread nationally and internationally," the authors warn in new pre-print study.
"Given the recent history of mpox outbreaks in DRC, we advocate for swift action by endemic countries and the international community to avert another global mpox outbreak," they added.
The researchers are calling for the roll out of "urgent measures", including expanded surveillance, contact tracing and targeted vaccination to contain the new outbreak.
Although the 2022/23 global outbreak was spreading primarily among networks of gay, bisexual or other men who have sex with men, it's unclear if it's following the same route of transmission.
The infection can cause unusual rashes and blisters
CDC/Getty Images
However, early signs suggest that this is the case: sex workers have aided its spread in Kamituga, accounting for 30 nearly percent of cases.
Some 85 percent of people had genital lesions, while 10 percent were hospitalised.
The research was led by Congolese scientists in collaboration with experts across Africa, Europe, the US and Canada.
The Michigan Department of Agriculture and Rural Development (MDARD) recently reported detections of highly pathogenic avian influenza (HPAI) in dairy herds in three more counties, including Ionia, where the virus struck for a second time at a massive layer chicken facility.
In other avian flu developments, Minnesota and New Mexico reported their first outbreaks in commercial poultry operations for 2024.
Michigan reported its first outbreak in dairy cows on March 29, which affected a herd in Montcalm County in the west central part of the state that had recently received cows from an affected facility in Texas.
In an April 12 statement, MDARD said the three additional herds in Michigan are located in three counties: Ionia, Isabella, and Ottawa. Ionia and Isabella counties border Montcalm County. Ottawa County is located on the western border of Michigan's lower peninsula.
Officials didn't specify the suspected source of the virus in the state's three latest detections.
"What is happening with HPAI in Michigan mirrors what is happening in states across the country. This virus does not stop at county or state lines, which is why we must all be on high alert," said Tim Boring, PhD, MDARD's director. "This news is unfortunate and upsetting for our poultry and dairy farming families and communities."
He said experts across the nation continue to assess the situation and are providing insights into the impact of HPAI on affected livestock.
This virus does not stop at county or state lines, which is why we must all be on high alert.
A day before the latest announcement, MDARDstrongly urged producers to tighten all biosecurity measures to reduce the risk of spreading the virus. "This is a virus that can easily be moved unknowingly on everything from farm equipment to shoes to delivery or service vehicles and the list goes on," Boring said.
Earlier this month, the virus struck a large layer facility in Ionia County that housed more than 1.9 million birds, marking Michigan's fourth detection in commercial poultry since 2022.
The latest updates from the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) notes a second outbreak in Ionia County poultry, this time at a commercial table egg processor that has more than 2.1 million birds.
APHIS also reported the first outbreaks in commercial poultry this year for Minnesota and New Mexico. Minnesota's outbreak occurred at a turkey farm housing more than 68,000 birds in Meeker County. In New Mexico, the virus was detected at a commercial hatchery in Roosevelt County that is home to 61,500 birds.
Elsewhere, the virus struck another poultry operation in Kansas, this time in Grant County at a location that has 17,700 birds, according to APHIS. Earlier this year, the virus hit a layer farm and multiple gamebird producers.
A bird flu outbreak in U.S. dairy cows has grown to affect more than two dozen herds in eight states, just weeks after the nation's largest egg producer found the virus in its chickens.
Health officials stress that the risk to the public is low and that the U.S. food supply remains safe and stable.
At this time, there continues to be no concern that this circumstance poses a risk to consumer health, or that it affects the safety of the interstate commercial milk supply, the U.S. Food and Drug Administration said in a statement.
Heres what you need to know about bird flu and food:
WHICH STATES HAVE FOUND BIRD FLU IN DAIRY COWS?
As of Friday, the strain of bird flu that has killed millions of wild birds in recent years has been found in at least 26 dairy herds in eight U.S. states: Idaho, Kansas, Michigan, New Mexico, North Carolina, Ohio, Texas and South Dakota.
The virus, known as Type A H5N1, has been detected in a range of mammals over the last few years, but this is the first time it has been found in cattle, according to federal health and animal agencies. Genetic analysis of the virus does not show that it has changed to spread more easily in people, the U.S. Centers for Disease Control and Prevention said.
HOW IS BIRD FLU AFFECTING FOOD PRODUCTION?
Agriculture officials in at least 17 states have restricted imports of dairy cattle from states where the virus has been detected, but, so far, government agencies say its had little effect on commercial milk production. Officials believe cows likely have been infected by exposure to wild birds, but said cow-to-cow spread cannot be ruled out."
Farmers are testing cows that show symptoms of infection, including sharply reduced milk supply and lethargy. Animals that show signs or test positive for illness are being separated from other animals on the farms. The animals appear to recover within two weeks.
U.S. egg producers are watching the situation closely after bird flu was detected in chickens in Texas and Michigan. Millions of birds have been killed, but the FDA said the risk of affected eggs getting into the retail market or causing infections in humans is low because of federal inspections and other safeguards.
DOES PASTEURIZATION KILL BIRD FLU?
Scientists say theres no evidence to suggest that people can contract the virus by consuming food thats been pasteurized, or heat-treated or properly cooked.
Its not a food safety concern, said Lee-Ann Jaykus, an emeritus food microbiologist and virologist at North Carolina State University.
Two people in U.S. have been infected with bird flu to date. A Texas dairy worker who was in close contact with an infected cow recently developed a mild eye infection and has recovered. In 2022, a prison inmate in a work program caught it while killing infected birds at a Colorado poultry farm. His only symptom was fatigue, and he recovered.
IS GROCERY STORE MILK SAFE FROM BIRD FLU?
Yes, according to food safety experts and government officials.
U.S. producers are barred from selling milk from sick cows and must divert and destroy it. In addition, milk sold across state lines is required to be pasteurized, or heat-treated using a process that kills bacteria and viruses, including influenza.
We firmly believe that pasteurization provides a safe milk supply, Tracey Forfa, director of the FDAs Center for Veterinary Medicine told a webinar audience this week.
IS RAW MILK SAFE FROM BIRD FLU?
The FDA and the CDC are less certain about unpasteurized, or raw, milk sold in many states, saying theres limited information about the possible transmission of the H5N1 virus in such products.
So far, no herds linked to raw milk providers have reported cows infected with bird flu, but the agencies recommend that the industry not make or sell raw milk or raw milk cheese products made with milk from cows that show symptoms or are exposed to infected cows.
U.S. health officials have long warned against the risk of foodborne illness tied to raw milk, which the CDC said caused more than 200 outbreaks that sickened more than 2,600 people between 1998 and 2018.
Still, raw milk proponents like Mark McAfee, owner of Raw Farm USA in Fresno, Calif., said the outbreak of H5N1 in commercial cows appears to have spurred higher sales of the products, despite federal warnings.
CAN YOU CATCH BIRD FLU FROM EGGS OR MEAT?
Only dairy cows, not beef cattle, have been infected or shown signs of illness to date, agriculture officials said.
The largest egg producer in the U.S. temporarily halted operations on April 2 after finding bird flu in its chickens. Cal-Maine Foods culled about 1.6 million laying hens and another 337,000 pullets, or young hens, after the detection.
The company said there was no risk to eggs in the market and that no eggs had been recalled.
Eggs that are handled properly and cooked thoroughly are safe to eat, said Barbara Kowalcyk, director of the Center for Food Safety and Nutrition Security at George Washington University.
A lot of people like runny eggs. Personally, if I eat an egg, its very well cooked, she said.
Still, Kowalcyk and others cautioned that the situation could change.
This is an emerging issue and clearly this pathogen is evolving and theres a lot that we dont know, she said. I do think that everybody is trying to figure it out as quickly as possible.
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By Bloomberg School of Public Health staff report
The H5N1 strain of avian influenzacommonly known as bird fluhas been circulating among wild migratory birds for the past two years, with substantial spillover into poultry farms.
But what's sparking concern among scientists and public health officials alike is the recent discovery of the virus in dairy cows and the subsequent infection of a dairy farm employeethe second person in America ever documented to be infected with H5N1. The virus has now spread to 16 herds in six states according to the United States Department of Agriculture, fueling concerns about potential further transmission to humans.
In this Q&A, adapted from the April 8 episode of Public Health On Call, Stephanie Desmon speaks with Meghan Davis, associate professor in the Department of Environmental Health and Engineering, and Andrew Pekosz, professor in the Department of Molecular Microbiology and Immunology, about H5N1's jump between species, what that means for the virus's pandemic potential, and what the appearance of the virus in dairy means for consumers.
Pekosz: This virus has been around for over 20 years. It's been mutating over time, and something happened in the last couple of years to cause an explosion of cases in wild birds. Not surprisingly, that's led to spillover infections in some poultry farms. There's also been an increase in mammals that have been infected, such as skunks, bears, and foxes, presumably from feeding on dead infected birds. And recently, we've seen spillover of this virus into dairy cows.
Cattle have not been reported to be infected with any of the influenza A viruseshuman or animalto date. Anytime this virus enters a new host, we set off some alarm bells in the scientific community to see what's going on.
Pekosz: I expect that over the next few weeks, we're going to be seeing more cases in cows and humans, because humans are in close contact with cows during many dairy processes. Hopefully, this will not be a large outbreak, but we certainly expect to see more cases.
Davis: I am surprised that it's in dairy cows, because when we think about animal models for influenza, we think about mustelids, like ferrets or mink. We have also seen a number of sick farm cats that tested positive. What is most interesting about seeing [H5N1] in dairy is that researchers haven't been focusing on biosecurity and biocontainment for things like avian influenzawhich is typically transmitted from a bird reservoir. Dairy farms are often quite open to the airbirds might spend time in areas where the cows eat, for example.
One of the other things we are seeing is some symptoms of disease in the cows. I've not heard of high mortality yet, but they have been showing fairly nonspecific signs, like not eating or milking well. Most of these tend to be somewhat older cows because adult cows who are lactating are in a different category of susceptibility than young calves. What we don't know yet is if perhaps the virus is in all the populations within the farm, and only some of them are showing symptoms.
Davis: For the average person buying commercial milk, we don't have any evidence that would suggest concern. If you buy pasteurized milk from a commercial dairy processor, the risk is extremely low. Pasteurization, which involves temperature and pressure and time, is designed to inactivate microbes to make the milk safer to consume and to give it longer shelf life. I strongly advise against consuming raw milk products, no matter where you live, because there are other risks, not just avian influenza.
Pekosz: Two things are really important. One is: The virus has gone from the respiratory tract through lots of different organs, through the blood, and made it all the way to the milk. In humans, the influenza virus stays within the respiratory tract. We have seen H5N1 move out of the respiratory tract in other animals, but usually that's associated with a really fast mortality. As soon as the virus leaves the lungs, the animals are so sick that they die. We're seeing a case here where the animals don't seem to be really sick, but the virus is making it to other parts of the animal. That's going to tell us something perhaps unique about the H5N1 virus compared to seasonal human viruses.
The second critical thing is: If there is spread of this virus from cow to cow, is the virus changing and getting better adapted to replicating or spreading in cows? Bird flu jumping to mammals is important because anything that allows the virus to adapt to a mammal has the potential for making it better able to infect humans. Understanding what happens now with the spread of the virus and how the sequence of the virus changes is going to be critically important. The first sequences [from cows] look like the virus is almost identical to the bird virus. But we haven't really sampled animals that presumably acquired the infection from other cows.
Davis: There is a lot of swapping of cows in the dairy industry, and there is a diverse population of farmers, each of them has their own way of doing things. And that means that we may need to educate farmers about perhaps restricting certain sales or trade of dairy cows if evidence shows that you could introduce avian flu through a cow brought in from outside the farm.
The USDA has released recommendations for state animal health officials, veterinarians, and producers, including trying to exclude birds and cats from areas where livestock are kept, not moving sick or exposed cows, using PPE among workers with exposure to dairy cows, and other measures.
Something I'm very interested in is: Where were each of these cows exposed? To what degree was this one event that is now spreading through these networks of sale and trade and movement of dairy cows? Or is this multiple events in which you've had an introduction [of the virus] from birds? Because that also changes the dynamics as we think about genetics and the potential for evolution.
Pekosz: It's also clear that the USDA has not ruled out that spread from cow to cow is happening via contaminated milking equipment because the amount of virus in the milk is much greater than what is found in the nose of infected cows. If this is contributing to virus spread, it should be straightforward to institute equipment disinfection protocols that could slow or stop virus spread.
Pekosz: H5N1 registers as what we call "a virus with pandemic potential." Humans presumably all have some immunity to H1 and H3 influenza viruses, which can cause seasonal epidemics, but they can't cause pandemics at the level of what we saw with COVID because there's just too much immunity in the population that limits the spread and dampens down disease severity.
However, the human population is essentially completely naivehas no preexisting immunityto H5 viruses. Therefore, similar to what we saw with COVID, in the worst case scenario, if this virus enters humans and starts to spread, all of us are susceptible, and we could see massive increases in numbers of cases.
H5 viruses are rather deadly in poultry. They're not so deadly in wild birds, but they seem to be deadly in mammals, and we don't know what they'll do in humans.
Davis: Right now, the average person should just be aware and avoid things like raw milk products. However, because we are seeing the potential for disease in cats, and we don't know yet if that came from cows or birds or some other pathwayit's a good idea to prevent your cats from having contact with wild birds. If they're indoors, keep them indoors, and if they become ill, consult your veterinarian.
This article originally appeared on the Bloomberg School of Public Health website.
A form of avian flu that has been devastating to the nation's poultry industry in recent years has now spread to cattle. Although one dairy worker in Texas has been infected, public health officials believe the risk of contagion to humans remains low, but they are on alert nonetheless.
The dairy workers only symptom was eye redness. He was treated and has recovered. But it was the first time this virus had passed from an infected mammal to a human, and the first time it had been found in cattle.
The viral strain in question, H5N1, was first detected in China in 1996. Since 2021, it has killed hundreds of millions of wild and domesticated birds. Fewer than 900 cases of human illness caused by the virus have been documented worldwide, the result of exposure to infected birds. Half of those who became ill did not survive.
Scientists who monitor the transmission of disease from animals to humans have long worried that a mutation of the virus could spark a dangerous pandemic. At present, there are no signs that this has occurred, and also no evidence of human-to-human spread of the virus. The risk to those who work with poultry and cattle is greater, but still low-to-moderate, according to health authorities. The CDC has issued recommendations for minimizing their exposure.
The threat to the population is low right now, says Adriane Casalotti, who heads government and public affairs for the National Association of County and City Health Officials (NACCHO). Public health officials are actively working behind the scenes to keep it that way or identify new threats if they emerge.
So far, USDA scientists haven't found that cows are actively shedding virus and exposing other animals. Even if milking is to blame for spread, it doesnt answer the question of how the virus came to be present in the first place.
The fate of the cows is another matter. So far, the USDA hasnt issued orders to quarantine cattle, but it recommends minimizing their movement. Some states are restricting the import of cattle from states with infected herds.
The USDA has required poultry farmers to cull flocks infected with H5N1, leading to the loss of 85 million birds to date. Nothing this severe is being suggested for cows, but there are big concerns about what could happen if the virus in them spreads to poultry and leads to new infections in flocks.
Theres already a safeguard against exposure to the virus in milk. One of the reasons we don't think that this will get to the general population is because milk is pasteurized, Casalotti says. States have a patchwork of guidelines regarding the sale of raw milk, however. Two of the states where infected cows have been found, New Mexico and Idaho, allow the sale of raw milk in retail outlets. Only one, New Jersey forbids its sale under any circumstances.
As the origins of cattle infections and their potential impact on dairy workers are investigated, the CDC has urged health departments to tighten relationships with agricultural agencies and veterinarians. "It is very, very important that state or local agricultural government agencies and workers are being very, very collaborative and keeping the public health side up to date, says Marcus Plescia, chief medical officer for the Association of State and Territorial Health Officials (ASTHO). That's the big ask here.
Marcus Plescia talks about the importance of collaborative communication between agriculture and public health.
(Gina Ferazzi/TNS)
Most fatalities from this strain of bird flu have occurred in developing countries. Its hard to know what the fatality rate might be in a country with higher levels of medical and supportive care if cases become more common, Plescia says. Only one other person in the U.S. is known to have been affected by bird flu, in 2022. They were exposed to an infected flock, and their only symptom was fatigue.
Even if the current risk is low, its enough to prompt urgent conversations about what ifs within the public health community. Our dependence on industrialized factory farms for our food supply increases the likelihood of such a public health emergency, Lieder says. Bills currently before Congress that would limit states' ability to set standards for such operations, combined with limitations on public authority enacted in the wake of the pandemic, would weaken both protections and regulators' ability to respond.
There needs to be a hard look at the public health systems continuing ability to act when serious threats emerge, says Brian Castrucci, CEO of the de Beaumont Foundation, which supports health efforts. Even if more transmission from cattle to humans occurs, tools exist to contain it, but may be effective only if public health departments are adequately staffed with trained workers. The foundation estimates that public health departments need 80,000 more full-time employees just to deliver basic services.
The countrys pandemic response capability is only as strong as the state that is least prepared, Castrucci says. This is an opportune time for every state to make a comprehensive pandemic preparedness plan that incorporates learnings from COVID-19, and for states and the federal government to look for ways to work together against diseases that pose national, not state-level, threats.
We spend a lot of time worried about China and Iran, Castrucci says. We need to be much more concerned about viruses that we havent even named.
Earlier this spring, California dairy farmers noted a puzzling drop in milk production in Texas, New Mexico, Idaho, Ohio, Kansas and Michigan. Weeks later, news broke that several herds in these states, as well as North Carolina, had been diagnosed with avian influenza the same strain that has devastated bird populations across the globe and shown a troubling ability to jump to mammals.
In an effort to prevent local herds from infection, officials in California and elsewhere have imposed restrictions on cattle imports from the affected states, while the U.S. Department of Agriculture has urged livestock managers to minimize the movement of cattle as much as possible.
Although the U.S. Centers for Disease Control and Prevention believes the current risk for the general public is low, the development has left dairy farmers reeling. Never before have U.S. dairy cows been infected with H5N1 bird flu viruses.
Nobody saw this coming, said Michael Payne, a researcher and outreach coordinator at the Western Institute of Food Safety and Security at UC Davis.
Scientists and health agencies across the globe have been tracking the spread of the virus for years.
Since 2021, it has killed hundreds of millions of farmed poultry and infected more than 48 species of mammals including humans as well as countless numbers of wild birds. It has also proved especially deadly among some communal mammals, such as elephant seals and sea lions in South America, as well as caged fur-farmed animals in Europe.
Nevertheless, outbreaks among dairy cows have come as a rude shock.
In addition to the cattle infections, a farmworker in Texas who was in close contact with infected dairy cows also became infected, but experienced only mild symptoms. This was the second known human case in the United States.
Despite the mildness of the farmworkers illness, the prospect of continued infections worries some.
The concerning trend of multiple states reporting cattle infections raises the likelihood of continued human exposure, said Suresh Kuchipudi, professor and chair of the University of Pittsburghs department of Infectious Diseases and Microbiology. This could amplify the risk of further virus adaptation, potentially facilitating human-to-human transmission.
Public health advocates, wildlife biologists and epidemiologists say there are a few reasons for why the cattle outbreaks have surprised farmers and officials.
First, while there have been sporadic infections of cattle via other flu strains in the past, no other avian flu has ever evolved the ability to pass between cows and other ruminants, said Kuchipudi.
That was surprising, he said. Totally unprecedented.
And second: There is no single federal or state agency responsible for following this disease one that affects wildlife, agriculture and public health. Some experts say its a flawed silo-like approach for a virus that concerns multiple government agencies here and in other nations.
This is a fundamental problem in our monitoring system, especially when it comes to emerging and zoonotic infections, such as the avian flu, said Kuchipudi. This is a public health problem, a wildlife problem and also a domestic animal problem, for which a one-health solution in which all three elements are included could really help in terms of managing information collection and communication.
For instance, while its still unclear how the cows got the disease, if farmers had been on the look-out for sick birds or wildlife and been communicating with wildlife agencies and their farm bureaus, the infection might have been contained, experts say.
Californias Department of Food and Agriculture is now asking farmers to be on the lookout for sick birds and mammals, and to take steps to humanely remove migrating birds and waterfowl that could come into contact with their herds, and prevent them from nesting nearby.
There is also a concern that the disease was passed via infected poultry litter a mix of poultry excreta, spilled feed, feathers, and other waste scraped from the floors of industrial chicken and turkey production plants which, in the United States, is used in cattle feed on some farms. UC Davis Payne said that in California, poultry waste is processed at high virus-killing temperatures, so it is unlikely to be a concern.
The practice is banned in the United Kingdom, European Union and Canada, where fears of spreading bovine spongiform encephalitis mad cow disease made such practices seem too risky.
Despite concerns voiced by some experts, California officials say existing bird flu monitoring efforts are effective.
State Veterinarian Annette Jones said that she works fluidly with multiple state and federal agencies, such as the U.S. Department of Agriculture.
We have veterinarians and experts spread throughout the state that can do those initial investigations. And if theres any inkling that there could be a human health issue, then we also work very closely with the California Department of Public Health, who has links to County Public Health and CDC, she said. To the outside person that seems probably like acronym soup, right? But to an inside person with experience, we know.
Jones and others in the dairy and agricultural sector say there is no reason for the public to be alarmed or concerned when it comes to avian flu-infected cattle.
They say infected cows seem to have a mild reaction and get better quickly. Also, milk is pasteurized, so if an infected cows milk were to get into the system, the virus would be killed.
Yet others say its the whats next question that is most worrying.
We want to address what is happening so that we can prevent something worse from happening, said J. Scott Weese, professor at the Ontario Veterinary College and director of the University of Guelphs Centre for Public Health and Zoonoses. That something worse is this virus becoming a virus that can be easily transmitted between humans and can cause serious disease.
The disease has already bucked all expectations from its ability to infect a variety of species to its international reach and duration, experts say. That should make its appearance on a mammal-based factory farm a cause for doubled-down surveillance and concern, said Crystal Heath, a Bay Area veterinarian and co-founder of Our Honor, an animal welfare organization.
You have hundreds, if not thousands of genetically similar animals all living in the same space, standing in each others waste and breathing on each other, said Heath. Its Shangri-La for an opportunistic virus.
And it is still unclear how widespread the virus is, or for how long its been infecting cattle, said Weese.
The fact that observers had noticed a drop in milk production in states now known to have infected herds suggests to some it may have been around for weeks or months. And if symptoms were mild enough in cattle and humans not to warrant a vet or doctors visit, it could be circulating and getting even more chances to evolve, said Weese including finding a mammalian host with a human and avian flu, allowing an opportunity to mix and recombine.
Which is why many are now looking toward factory pigs and swine, said Matthew Hayek, assistant professor of Environmental Studies at New York University in the Department of Environmental Studies. Pigs are considered effective and concerning flu-recombination factories mammalian vessels that mix human and bird flu viruses with potentially lethal ease.
Thats a problem not just for the sake of our food production, he said, but for the sake of our safety as a species.
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Bird Flu, or Highly Pathogenic Avian Influenza Virus, is back. The virus has stalked flocks across the nation for about 20 years now, but for the first time there has been a recorded case of a human infection. Despite this, officials said there is very little threat of infection for humans.
Amanda Potter is the Agriculture and Natural Resources Cooperative Extension Agent in Rowan County. She said as of right now there have only been two confirmed cases of Bird Flu in Kentucky with the recent outbreak, two snow geese in Henderson County.
Despite that, she said it is still important for people to know the signs and symptoms of Bird Flu to protect domestic flocks.
The main symptoms that people are told to look out for are issues with coordination, you may notice droopy wings, lethargy, unwillingness to fly if it is a type of avian that can fly. Of course, things like chickens arent really known for their willingness to fly anyway, said Potter.
Additional signs are head tremors and odd behavior like ducks who seem to want to swim in circles.
Potter added that there are steps people can take to protect themselves and other flocks of birds from infection.
Dont harvest, handle, or consume any birds that appear to be sick, or that you found that have already died. Make sure you are harvesting waterfowl outside or in a well-ventilated area. Make sure youre disinfecting any equipment or tools, and then of course dont eat, drink, smoke, bring your hands to your mouth if youre cleaning these game birds, said Potter.
If someone suspects a bird might be infected, Potter said to contact their local extension office, or the veterinary diagnostic lab at the University of Kentucky, which has after-hours service. She added that more general information can also be found at local extension offices.
Topline
Bird flu has spread between farm mammals in at least five states this year, and health agencies note pets like cats and dogs may be susceptible if theyre exposed to infected animals, though transmission to humans is unlikely.
dog and cat, looking out the window together
Bird flu (also called avian flu) refers to a group of potentially deadly infections caused by avian influenza Type A viruses, and typically infects domestic poultry and wild migratory birds.
Although bird flu usually spreads between birds, it is possible for the infection to spread to mammals like domestic dogs and cats, according to the Centers for Disease Control and Prevention.
Domestic animals can become infected with bird flu if they eat or are exposed to sick or dead birds that are infected with the virus, and cats are the most susceptible domestic animals to become infected, according to the Kentucky Department for Public Health.
Although it can occur, the chances of people catching bird flu from their pet dogs and cats are extremely unlikely, according to the American Veterinary Medical Association.
Symptoms of bird flu in cats and dogs include a fever, lethargy, loss of appetite, difficulty breathing, conjunctivitis (or pink eye)and neurological signs like seizures and tremors, and death is also a possible outcome.
The Department of Agriculture announced bird flu was detected in dairy herds in Texas and Kansas on March 25. The agency later discovered dairy herds in Michigan, New Mexico and Idaho were also infected. Minnesota also reported a case of bird flu in a goat on March 20, which is the first case of infection in a domestic ruminant in the U.S., referring to many common grazing mammals in the U.S., including domestic cattle, according to the AVMA. On April 1, Texas officials announced the second known case of a type of bird flu called H5N1 in a person in the U.S., which was spread from exposure to cattle. The first occurred in 2022 when a person in Colorado contracted the disease from infected poultry. This case does not change the risk for the general public, which remains low, according to the Texas Department of State Health Services announcement. The patient reported eye redness as their only symptom, and is being treated with antiviral medication, the CDC reports. Though human infection is rare, there have been 887 reported cases between January 2003 and February 2024 in 23 countries, according to the World Health Organization. The virus can be extremely dangerous for humans who are infected, as 52% of these cases ended in death.
A veterinarian in New York City was infected with H5N7, a type of bird flu virus, after caring for infected cats admitted into an animal shelter in November 2016, according to a study published in Clinical Infectious Disease. The cat died a few days later, and further testing discovered the virus spread throughout the facility to several other shelter cats, though other animals like dogs werent infected. No one who came into contact with these catsincluding the 165 volunteers and employees, and over 180 adopterswere suspected of having the illness, except for the visiting veterinarian. This person had prolonged exposure without face protections with infected cats and their secretions. The veterinarian had a mild illness, which included a sore throat, cough and muscle pain, though they were treated and cured with medication without hospitalization.
The Food and Drug Administration has approved a few bird flu vaccines for humans. The U.S. has a small stockpile of vaccines for two bird flu viruses (H5N1 and H7N9), but it wouldnt be enough to vaccinate all Americans if an outbreak were to happen among humans. If an outbreak among humans does occur, the government plans to mass produce vaccines, which can take at least six months to make enough for the entire population. Sequirs, the maker of one of the approved vaccines, expects to have 150 million vaccines ready within six months of an announcement of a bird flu pandemic. Because there are 8 billion people on the planet, that means less than 2% of the world population will receive the vaccine after the first six months of a potential outbreak.
