It's not just President Biden who recently tested positive for COVID cases of the virus are spiking across the country.
Nearly 40 states are reporting high COVID activity levels, according to data from the Centers for Disease Control and Prevention, and emergency room visits are at their highest for the virus since February.
Why the seemingly sudden summer surge? There are a couple of factors at play, Dr. Cline Gounder, CBS News medical contributor and editor-at-large for public health at KFF Health News, told"CBS Mornings" Wednesday.
"One, the virus continues to evolve to stay ahead of our immune systems. That's what we can talk about when we're talking about variants," she said. "Two, your immunity to infection only lasts about three months. Your immunity to severe disease, hospitalization and death, that lasts much longer, which is why people are not getting sick the way they were early in the pandemic. But it is to be expected that every few months, maybe twice a year or so, we'll see a big wave of COVID across the country."
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More reasons for increased numbers? People are traveling and spending more time indoors and not masking as much, Gounder added.
These reasons add to the concerning potential for a COVID-19 outbreak to spread within the tightly confined 2024 Summer Olympics, as thousands of athletes and spectators from around the world have descended on Paris.
Current guidelines, however, can help keep people safe.
"You should be staying away from others for at least 24 hours, at least until your fever resolves without the help of a medication like Tylenol, and your symptoms are improving," Gounder said. But you should, as much as possible, take additional measures "for at least five more days, which is when you're most infectious, most likely to transmit to other people."
Options for this include:
Gounder also urges people to use "common sense" when it comes to COVID testing and precautions.
"If you're feeling sick, probably should get tested. When you're feeling sick, probably shouldn't be around other people to the degree that you can avoid that," she said. And masks, "contrary to some opinions, do work to protect you if you're wearing a N95 or KN95 mask, and they also work to protect other people if you're infected."
Sara Moniuszko is a health and lifestyle reporter at CBSNews.com. Previously, she wrote for USA Today, where she was selected to help launch the newspaper's wellness vertical. She now covers breaking and trending news for CBS News' HealthWatch.
TEXAS (KXAN) The Centers for Disease Control and Preventions National Wastewater Surveillance System is detecting high concentrations of COVID-19 nationally including here in Texas.
The CDC program monitors wastewater systems for COVID-19 viral activity to get a better understanding of how much viral load is in a given community. Nationwide, only one state New York is reporting low viral activity, with the rest ranging from moderate to very high levels. North Dakota is the sole state not reporting any day due to a lack of testing sites.
Here in Texas, the Lone Star State is reporting very high viral activity levels, based on reporting from 19 wastewater detection sites.
The Texas Department of State Health Services receives COVID-19 case counts and associated rates on a voluntary basis, with individual confirmed and probable case reporting no longer a state mandate as of early March.
Based on voluntary figures, Texas current respiratory virus surveillance report released July 19 found COVID-19 cases increased in Texas by nearly 32% July 7-13 compared to the previous weeks levels. In the year to date, Texas has detected more than 238,000 confirmed and probable cases of COVID-19, based on voluntary reporting.
This increase in viral load is on par with previous COVID-19 seasonality trends monitored by the CDC. While there isnt a distinct COVID-19 season like there is for the flu and other respiratory conditions, historic CDC reporting found COVID-19 cases, hospitalizations and deaths tend to trend upward in the wintertime (during December and January, primarily) as well as the summer (typically, during July and August).
The CDC added the emergence of new variants also contributed to COVID-19 activity levels peaking at different points. Variants like Delta and Omicron were responsible for several upticks, with higher detection during the winter and summertime.
Locally, members of Austin Public Healths epidemiology team said theres no clear cause of summer COVID-19 surges, but some factors might contribute to them.
Possible reasons include that people tend to socialize and travel more in the summertime, an APH spokesperson said in an email to KXAN. Additionally they likely have decreasing immunity from vaccinations that were obtained during the previous fall or winter.
The CDC recommends the following measures as essential strategies to mitigate contracting or spreading COVID-19:
Beyond these measures, extra preventative efforts include using masks while in public, practicing social distancing and taking tests if you come into contact with someone who tested positive for COVID-19 or suspect you have it yourself.
If you do test positive, the CDC encourages people to stay home and away from others until youve been fever-free without medication for 24 hours and your symptoms have improved in the past 24 hours.
Beyond that, patients are encouraged to take added precautions during the following five days after symptoms have decreased and their fever has broken.
Austin Public Health offers resources online for where to find COVID-19 vaccines, testing options and treatment locally.
Colorado is leading the nation in human cases of the H5 bird flu and millions of poultry in the state have been killed to stop the threat of the virus. It also has hit dairy cows in the state.
What does this mean for the general public? What about all the county and state fairs that show off chicken and cows?
Avian influenza, also called H5 bird flu or H5N1, is a highly pathogenic avian influenza. Its widespread in wild birds around the globe. Its responsible for outbreaks in poultry and dairy cows in Colorado and the U.S., with double digit recent human cases in agricultural workers.
The virus is found in an infected birds poop and fluids from the birds mouth, eyes and nose, according to the CDC.
It can cause severe respiratory symptoms.
The viruses dont usually infect people, according to the CDC, but can happen if you come into contact with an infected bird, dead or alive and touch your eyes, nose or mouth, touch surfaces or handles item contaminated and tough your eyes, nose or mouth, or breath virus-contaminated dust or droplets.
If you get sick from it, symptoms range from none to severe illness. Mild symptoms include conjunctivitis (red eye), cough, sore throat, runny or stuffy nose, muscle or body aches, headaches and tiredness. Among more serious symptoms are high fever, shortness of breath and difficulty breathing. Severe illness can result in pneumonia that may require hospitalization and can lead to death, though thats only to date happened in other countries, not the U.S.
Most at risk are people working with infected poultry, waterfowl, including ducks and geese and livestock.
It is safe to eat properly handled and cooked poultry products, according to the Colorado Department of Public Health and Environment (CDPHE). The proper handling and cooking of poultry, meat, and eggs kills bacteria and viruses, including bird flu viruses.
People should separate raw poultry from cooked foods and foods that won't be cooked.
We (the state health department) and CDC believe that the risk continues to be low here for the general public, said Dr. Rachel Herlihy, the state epidemiologist with CDPHE.
Many experts and health agencies advise against consuming raw milk. Always choose pasteurized milk and dairy products to protect your health and the health of your family, the CDC wrote on its web page regarding raw, or unpasteurized, milk.
The CDC suggests health care providers tell patients raw milk and any products made from it, including cheese, ice cream, and yogurt can be contaminated with germs that can cause serious illness, hospitalization, or death.
The more virus out in farms or the wild, the greater the chance it will infect other animals, including humans. Also, more infections means a greater possibility that virus could mutate into a much more serious threat, one that could cause a pandemic.
H5N1 registers as what we call a virus with pandemic potential, according to the Johns Hopkins Bloomberg School of Public Health. Unlike other flu viruses, humans have no preexisting immunity to 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.
May Chu, an epidemiologist and clinical professor from the Colorado School of Public Health, said thats one key reason infected poultry are culled: to limit rapid spread through a flock that could then be transmitted to humans.
You can nip it before it gets into the human population widely, she said. That is the best public health protection.
The state health department cited the CDC and said that people who work on those farms are at higher risk of being exposed to H5 bird flu.
And that is showing up in Colorado.
As of Thursday, the state health department said it has recorded a total of 10 cases; six at one poultry operation and three at another. Thats in addition to the case of a dairy worker earlier this month, the states first case this year.
The risk to the general public is still low. We are only seeing this in workers with direct contact with these animals, said Scott Bookman, senior director for Public Health Readiness and Response with the CDPHE.
People who are in close contact with dairy and egg-laying facility workers who tested positive are being monitored as well, said Herlihy.
We want to know if there is any illness among household contacts, Herlihy said. That would obviously be a concerning scenario. So the folks that have closest contact with an ill worker would be our highest priority, and that has not been identified to date.
Herlihy said there has been no sign of the virus spreading via human-to-human transmission.
We've been tracking this virus since 2022, and during that time we have not seen evidence of person-to-person transmission, she said.We know that there's going to be increased exposure in certain industries, including the poultry industry and on dairy farms right now.
We also have had behavioral health services out there, not only working with our teams, but working with the workers out on site to ensure that if folks are struggling, that we've got people out there they can talk with, said the agencys Bookman. We also have our Agricultural Workers service program that has been out the last couple of days as well.
Colorado is providing up to four weeks of free PPE (personal protective equipment) to farmworkers, according to its website. There it also offers updated situation reports, links to a webinar via YouTube. A link for poultry owners, veterinarians and backyard, hobby and commercial products to report, in English or Spanish, information about sick or dead animals.
Similar resources are also available on the states website for HPAI in dairy cattle. That includes information about the state order regarding licensed dairy cow farms in the state to submit weekly milk samples for testing. Farmworkers can also order free PPE from the site.
Workers are also getting information, testing and monitoring from health providers visiting the facilities via mobile clinics. We outreach to seasonal workers, migrant workers, and other workers that may have a hard time, because of their work schedules, to come in, said Dr. Mark Wallace of Chief Clinical Officer for Sunrise Community Health.
While your risk of coming into contact with a sick animal at the fair is low, there are things you can do to protect yourself.
For the general public, what I would say to anybody at all times is wash your hands. Don't touch your mouth, don't put your hands on your face. Things like that, Scott Bookman said.
For animals, the state veterinarians office did put out guidance for poultry and dairy cows that recommended monitoring animals for signs of illness. The office said if you are bringing lactating dairy cattle to a show or event of some kind, that they should be tested within seven days of arrival.
We know that there's no such thing as no risk, Baldwin said. What we're trying to get to is low risk. And so testing within that seven day timeframe will help us be assured that at that time of that test, that cow was not shedding virus. So I think we are putting that in place and we're asking show and fair and event organizers to implement that guidance and require testing for those lactating dairy cattle going to fairs.
As for poultry, the state wont require testing because poultry show obvious signs of illness when infected with H5 bird flu.
All of the animals, when they get to the fairgrounds, are inspected, said Baldwin, the state veterinarian. So we've got teams from CSU, the CSU avian health diagnostic team that goes out and they do at a number of the fairs across the state, they'll do inspections at check-in for all of the poultry coming to those events.
Some veterinarians and agricultural experts nationally are recommending farmers not bringing lactating cows to fairs Given the high risk posed by lactating dairy cattle to other cattle, the rest of the exhibition community, and the public, lactating dairy cattle should not attend exhibitions including county and state fairs, at this time, according to a paper published by the University of Minnesota Extension and its College of Veterinary Medicine.
The risk to domestic animals is lower than in birds, but cats or dogs could become infected. That can happen when they go outside and eat or are exposed to sick or dead birds infected with bird flu viruses. That risk extends to an environment contaminated with infected bird feces.
People should keep their pets away from wild birds and from areas contaminated with the virus.
If you suspect your pet may have been exposed to H5 bird flu, and is showing symptoms of illness, contact your veterinarian and monitor yourself for symptoms.
Farm workers can protect themselves by wearing protective clothing like coveralls, gloves, face masks or shields, and goggles when working with sick or dead animals, manure, or milk, according to the states website. The state also suggests washing hands with soap and water throughout the day, especially before eating, drinking or smoking, and before going home. They recommend cleaning areas that have come in contact with animals, manure or milk and using chemical disinfectants effective against viruses.
If you work animals suspected or confirmed to have H5 bird flu and you start to feel sick, call CDPHE at 303-692-2700 (after normal business hours: 303-370-9395). The Department can help you get a flu test and medicine if you need it.
If you have questions about sick or dead animals on the farm, ask your farm manager and veterinarian.
The bird flu has been circulating in the migratory bird populations for the last two and a half years. Colorado State Veterinarian Maggie Baldwin said it has historically impacted the states poultry operations.
We have seen peaks and valleys of incursions because the virus has come in with migratory birds and typically leaves with migratory birds, Baldwin said.
The mortality rates for birds that are infected are between 90 percent and 100 percent. Thats what highly pathogenic avian influenza means: it kills a lot of birds.
They get sick very quickly and die very quickly, said Colorado Veterinarian Baldwin. For the last two and a half years, we've had single spillover events from wild birds that have been spilling over this virus into our poultry flocks. And what changed significantly is that jump into dairy cattle earlier this year.
Because the virus spreads so widely in birds and can spread to humans, infected poultry flocks, like those in commercial egg operation, are culled or put down.
Colorado has what the state vet calls sustained virus in dairy herds, meaning its continually present. It was actually the dairy cows that infected poultry in the state, Baldwin said.
We've had three spillover events into three large commercial flocks. Two of those are confirmed that they are the dairy strain. We're waiting on whole genome sequencing on the last one, but that has impacted three commercial poultry flocks, Baldwin said. And so this virus right now is not only challenging and putting strain on our dairy industry, but this spillover from dairy to our poultry industry is what is posing a really significant risk.
Colorado has begun mandatory testing of all cattle in the state to help control the spread of the virus among herds.
The Colorado Department of Agriculture and CDPHE announced July 23 that they are now requiring dairy farmers to submit weekly samples for testing. Colorado is the first state in the U.S. to implement a testing requirement.
The testing is to get a better handle on how widespread the virus is among cattle.
Our goal in implementing the mandatory testing order for the dairies statewide is really to identify what that reservoir of disease is Baldwin said
Baldwin said that their current process is to place herds that test positive for the virus in quarantine, then work with cattle owners to implement really strong biosecurity measures to try and prevent further spillover from that herd.
The state is tracking testing on its website.
Cows bred for meat do not need to be tested, as H5 bird flu cases have only been confirmed among dairy cattle.
It all started pretty recently, with three flocks needing to be culled in Welc County the first one was confirmed positive for the virus on July 8. The second one was confirmed on July 16 and the third on July 19.
State Veterinarian Baldwin said about 3 million laying hens were killed (or depopulated as Baldwin called it). It was more than half of the states total inventory of laying hens, she said. There were 5.2 million egg-producing hens in Colorado two years ago. She said two of the facilities where flocks were culled were egg laying operations.
They were, I believe, our two largest egg laying facilities in the state. And the third one was a commercial pullet facility. Pullets are the baby birds before they become laying hens. Baldwin said.
There is compensation and USDA has a program in place. Gov. Jared Polis declared a disaster emergency after the first outbreak was detected at a large commercial egg operation in Weld County. That freed up state resources to help agriculture officials and farmers respond to the situation.
So they are provided indemnity for the lost birds as well as the lost eggs at that facility. And they're also provided compensation for all of the activities associated with response to the disease, said Baldwin.
No one knows, but if the COVID-19 pandemic has taught anything, its that viruses can spread widely, around the world, like wildfire and that protective measures can help greatly avoid the worst.
It started out ravaging the poultry industry, but bird flu made the jump to US cattle this year and has beenimpacting the dairy industrysince spring, thinning the virus' line between where it's stayed so far (spreading between animals) and contact with humans.
This month, ahandful of new bird flu cases in farm workers from Colorado who had direct contact with sick birds were discovered. While they weren't the first human cases, the new cluster of cases prompted more concern the virus may one day start spreading from person to person and pose a greater health threat to people. It also called attention to the way some people are tasked with handling affected birdsin potentially dangerous ways and the risks to their health, as NPR reported.
Importantly, the Centers for Disease Control and Prevention maintained that the threat to the general publicis low; in the US, all confirmed bird flu cases since the outbreak began have been mild and confirmed in people with direct contact with animals -- not the general public. Still, health officials have been taking steps to curb the spread of avian influenza (specifically, H5N1 or "bird flu") by ramping up their monitoring of the virus and preparing for the worst-case scenario. The US Department of Health and Human Services announced in early July that the government is providing Moderna $176 million to develop its influenza mRNA vaccine, which could be used in the case bird flu ever became a pandemic.
As long as animals and humans live, work and gather around each other, there will be a risk of viruses mutating enough to make the jump from species to species. Fortunately, bird flu in humans so far has been rare, in part because the virus doesn't spread that easily from animals to humans, or between humans, although sporadic cases have occurred in other countries as well as the US.
Here's what to know about bird flu, or avian influenza, and what it looks like in people.
Bird flu started as a poultry and bird issue in the US but has spread to cows, which frequently have close contact with people and further the risk of the virus making the jump to humans one day.
In short,bird flu, aka avian influenza, is a type of flu that spreads between some animals and is currently causing outbreaks among birds and cattle in the US. Scientists are watching it closely for mutations that could make it easier to spread between people, because while it isn't currently able to spread between people, if it gained the ability to do so it would pose a major public health threat.
More specifically, bird flu is a disease caused by infection with an influenza type A virus, and is either "highly pathogenic" or "low pathogenic;" the current H5N1 outbreak strain is highly pathogenic.
Bird flu was first detected and controlled in 1997, but itreemerged in 2003 and started spreading widely among birds.
The World Health Organization reportsfour types of influenza viruses: A, B, C and D. Type A viruses, which occur in both humans and different kinds of animals, are the biggest threat to public health and can cause pandemics, the WHO says. The"swine flu" of 2009's pandemicwas caused by a type A virus.Seasonal flu virusesin humans are caused by type A and type B viruses.
Bird flu has been ravaging the US poultry industry for the last couple of years, resulting in the culling (killing) of millions of infected or potentially infected birds.
According to information last updated by the CDC on July 19, there have been at least 11 reported human cases of H5 (highly pathogenic) bird flu in the US since 2022, which is when the outbreak in birds kicked off in the US.
Human cases remain rare, but bird flu is considered a serious threat to public health because of its historically high mortality rate --about halfof bird flu H5N1 in people have resulted in death since tracking began, according to WHO information. No deaths from bird flu have been reported in the US; people who've tested positive for the virus had direct contact with sick animals and exhibited mild symptoms.
There haven't been any reports of people getting bird flu in the US from drinking milk or eating meat from birds or cows. The commercial food supply, which makes up most food you'd get in a regular grocery store, is regulated and meat from impacted animals shouldn't make it to store shelves.
There have been fragments of inactive bird flu virus found in pasteurized milk samples since the virus started spreading to cows, the high-temperature pasteurization process inactivates any virus or bacteria, including bird flu, that could make people sick. Infectious virus has been found in raw milk, and the US Food and Drug Administration is reiterating the general health risks of drinking raw milk, not just in terms of bird flu but also for other pathogens that often live in unpasteurized milk.
In terms of meat,cooking ground hamburger meat is also expected to inactive or kill the bird flu virus, according to the Department of Agriculture. The same is true for poultry; according to the CDC, cooking eggs and poultryto an internal temperature of 165 degrees Fahrenheit kills viruses, including bird flu.
Beyond cooking your food thoroughly, it may be difficult to catch influenza from food or drinking sources anyway, according to infectious disease experts we've spoken to in the past since influenza (which bird flu is) is a respiratory virus.
If you work directly with animals or livestock, which would include the event you work on a farm or even visit a fair where there's livestock, the CDC has specific tips for safety to reduce the risk of spread.
PHOTO PROVIDED Nadine Houck, a manager at the Penn State dairy barns, collects a sample of milk from a bulk tank for avian flu testing. The College of Agricultural Sciences announced it would support state surveillance efforts for highly pathogenic avian influenza in dairy cattle by testing Penn States herd for the virus.
UNIVERSITY PARK Animal health experts in Penn States College of Agricultural Sciences have announced that out of an abundance of caution they will test the Universitys dairy herd for highly pathogenic avian influenza, or HPAI, under a voluntary state testing program.
The announcement comes amidst an outbreak of bird flu that has affected dairy cattle in more than a dozen states since March. As of July 19, the virus had not been found in Pennsylvania dairy herds, according to the U.S. Department of Agriculture and state animal health authorities.
The Pennsylvania Department of Agriculture has encouraged all dairy farms in the state to enroll in its Lactating Dairy Cow Health Monitoring Program. The voluntary program is aimed at providing critical data on the status of dairy herds in Pennsylvania and detecting HPAI as quickly as possible should it arrive in the commonwealth.
The state herd monitoring program calls for conducting a weekly test of milk from a farm for three weeks, said extension veterinarian Ernest Hovingh, who is also a clinical professor of veterinary and biomedical sciences and director of Penn States Animal Diagnostic Laboratory. If all tests are negative and no clinical signs of the disease are observed, the herd is considered unaffected. At that point, weekly testing would continue, to ensure that the herd remains free of the virus.
He noted that unaffected herds are cleared for interstate transport of animals without any additional testing. For herds that do not participate in the monitoring program, Department of Agriculture regulations require testing of animals prior to movement across state lines.
Because Penn State does not move dairy cows across state lines, our herd has not been subjected to testing so far, Hovingh said. But participating in this program will allow us to determine if our herd is in fact HPAI-free, as strongly expected, and also will provide additional data to inform state and national surveillance efforts.
The chances of getting a positive test result are very remote, he added, but if that happens, Penn State and state officials will immediately investigate further.
Penn State attending veterinarian Jacob Werner, who oversees the health and well-being of all University livestock, said he and managers at the Penn State dairy barns have seen no signs to suggest that the virus is present in the herd, but it will be good to have testing data to confirm those observations.
We have a biosecurity plan in place to minimize the chances of bringing any diseases, including HPAI, into our herd, and we screen for sick cows regularly and consistently, Werner said. Drops in feed intake and milk production are two hallmark signs of most affected herds, and we monitor closely for those symptoms. We also dont import any animals into our herd, which appears to be the biggest risk factor for introducing HPAI infection to dairy herds.
Even in the unlikely event that the testing of Penn States herd brings back a positive result, Hovingh pointed out that in accordance with the U.S. Food and Drug Administrations Pasteurized Milk Ordinance, milk from sick cows does not leave the dairy and, therefore, does not enter the food supply.
In addition, all milk from Penn State cows is pasteurized before being sold for human consumption, he said. Numerous studies have shown that pasteurization inactivates pathogens such as avian flu viruses, and the FDA has confirmed that pasteurized milk and milk products are safe for human consumption.
Penn State will release the HPAI status of its dairy herd after the initial series of three weekly tests is completed, Hovingh said.
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Bird flu snapshot: This is the latest installment in a series of regular updates on H5N1 avian flu that STAT is publishing on Monday mornings. To read future updates, you can also subscribe to STATs Morning Rounds newsletter.
Public health experts whove been following the surprising spillover of H5N1 bird flu into Americas dairy cattle herds now have all eyes on Colorado, waiting to see if a cluster of human cases there might balloon into something bigger.
On July 14, Colorado officials announced that five workers involved in the culling of 1.8 million chickens at a large H5N1-infected egg farm in Weld County had tested positive for the virus. And the strain infecting the workers appears to be closely related to the virus infecting cows in Colorado and at least 12 other states.
On Friday, the Centers for Disease Control and Prevention confirmed a sixth case among the Colorado poultry workers. Almost 70 individuals involved in the depopulation operation were tested for H5N1 after showing symptoms of the disease, according to a spokesperson for the Colorado Department of Public Health and the Environment. On Saturday, the state announced it had found a possible seventh human case; the CDC, which must conduct confirmatory testing, is expected to receive the sample on Tuesday.
The six Colorado cases were all mild, with some experiencing the more traditional flu signs of fever and cough, and others having conjunctivitis, a symptom thats been seen with some of the dairy workers whove been infected during the outbreak. But its the first time multiple human cases have been reported on a single farm in the U.S., raising questions about whether the virus has changed or the environmental factors presented unique opportunities for it to spread.
A recent study led by noted flu virologist Yoshihiro Kawaoka of the University of Wisconsin-Madison found evidence that the virus now circulating inside cows has acquired some ability to bind to receptors found in the upper respiratory tracts of humans, though other labs have produced conflicting data. The concern with a large cluster of human cases is the increased potential for those people to pass on the virus to others, particularly immunocompromised individuals.
But Michael Osterholm, director of the University of Minnesotas Center for Infectious Disease Research and Policy, said without more data, its too soon to say what the risk is with the situation in Colorado. If we get 7, or even 70 more cases of conjunctivitis, what does that mean? Could this be a precursor to a respiratory infection, to influenza being transmitted people to people? No one knows.
He pointed to the situation in Michigan earlier this summer, where 54 farmworkers who had been exposed to infected cows and experienced some flu-like symptoms were tested by state public health officials. Only two of those individuals tested positive for H5N1.
Results from a serological study of farmworkers in Michigan released by the CDC Friday provide additional reassurance that asymptomatic human infections are not going undetected. None of the blood samples collected from people who had been exposed to infected dairy cows on two farms but showed no symptoms were found to contain H5N1 antibodies, meaning they had not been infected.
Further back in time was an outbreak of a different strain of avian influenza that struck commercial poultry farms in the Netherlands in February of 2003. Nearly 500 farmworkers registered health complaints, and while some complained of flu-like symptoms, and one veterinarian died, the majority experienced only conjunctivitis. Eighty-nine of those people tested positive for the bird flu virus, and all the cases were linked to direct contact with poultry. But the outbreak never spread more widely; by the next year it had largely burned out.
Clearly were vulnerable to H5N1 when its floating in the air, Osterholm said. Our bare eyeballs are a perfect landing spot for it. But theres a big difference between that and the virus taking hold in the human respiratory tract.
During a news briefing Tuesday, federal officials said Weld County workers faced challenging conditions inside the poultry facilities. Temperatures that exceeded 104 degrees and high-powered fans made it difficult to wear the protective equipment, including full-body suits and N95 masks, meant to protect them from the virus, particularly if it becomes aerosolized.
The workers were finding it hard to maintain a good seal or a good fit, either between the mask or with eye protection, said Nirav Shah, the CDC principal deputy director. This confluence of factors may play a role in explaining why this outbreak occurred, where it did, and when it did.
Initial genetic analyses have indicated that the virus sickening the poultry workers is related to the version thats spreading among cows, but its still unclear which dairy farm it came from. The state is in the early stages of conducting an investigation to understand those linkages, and has requested additional epidemiology support from the U.S. Department of Agriculture. The CDC on Friday said genetic sequencing of the virus infecting one of the poultry workers showed it was closely related to the first Michigan case and does not have changes associated with antiviral resistance.
Weld County, just northeast of Denver, is home to 350,000 people and the largest concentration of dairies in the state. So its no surprise its been especially hard-hit by H5N1, Colorado State Veterinarian Maggie Baldwin told STAT in an interview last week. Geography is a really big factor, she said. The fact that most of our dairies in Colorado are in the same region is going to lead to more transmission of this virus.
Colorado has been dealing with H5N1 on its poultry farms since early 2022, but until this summer, those outbreaks were sporadic and linked to wild birds. What we have now is sustained mammal-to-mammal transmission of H5N1 in dairy cows, which is leading to a potential source of continued spillovers into our poultry operations, Baldwin said. So this is even riskier than what we have been seeing for the last two and a half years.
Since its first reported case of bird flu in dairy cattle in late April, Colorado has registered 41 additional H5N1-positive herds, with six in the past week alone. That means infections have been reported in 40% of Colorados herds. It now leads the nation, making up nearly a quarter of the 163 livestock outbreaks in the USDAs official tally.
Correction: An earlier version of this story had an incorrect number of people who tested positive for bird flu during the 2003 outbreak in the Netherlands.
Of all the news about bird flu, this month has brought some of the most concerning yet. Six people working on a chicken farm in Colorado have tested positive for the virusthe biggest human outbreak detected in the U.S. The countrys tally is now up to 11 since 2022, but thats almost certainly a significant undercount considering the lack of routine testing.
Since the current strain of bird flu, known as highly pathogenic avian influenza H5N1, began spreading around the world in late 2021, it has become something like a super virus in its spread among animals, Richard Webby, an influenza expert at St. Jude Childrens Research Hospital in Memphis, told me. Wild birds have been decimated, as have poultry farms: The virus has been detected in more than 100 million birds in 48 states. H5N1 has been around for longer than 25 years, but only recently has it regularly jumped to mammals, infecting cats, sea lions, and bears. In March, it was detected for the first time in American cattle and, since then, has already spread to 163 herds in 13 states.
All of that would be worrying enough without reports of people also falling sick. Everyone who has tested positive in the U.S. has worked closely with farm animals, but each additional case makes the prospect of another human pandemic feel more real. Thats absolutely the worst-case scenario, Webby said. Its a possibility, although not the likeliest one. For now, the virus seems poised to continue its current trajectory: circulating among wild birds, wreaking havoc on poultry farms, and spreading among cattle herds. That outcome wouldnt be as catastrophic as a pandemic. But its still not one to look forward to.
Even with the spate of farmworker infections, the threat of bird flu to humans is, at the moment, considered low. Researchers are keeping an eye out for two red flags. The bigger one would be the viruss ability to spread between people. All of the people who have tested positive in the U.S. were infected by exposure to sick cows or poultry, and they have not seemed to pass the virus along to anyone else. Symptoms have generally been mild, including respiratory issues, though several people have developed serious cases of conjunctivitis, or pink eye. (No one in the U.S., or globally, has died from this variant of H5N1.) There is no evidence at this point that this virus is going human to human, and therefore it really does not pose a threat to public health, Jenna Guthmiller, an immunologist at the University of Colorado Anschutz School of Medicine, told me.
The second warning sign is how the virus itself is changing. So far, H5N1 isnt very good at getting into human cells and then replicating inside them, abilities that would enable the viruss spread among people. But that may be changing. In a lab study, virus particles from infected cows showed signs that they were capable of binding to human receptors in the upper respiratory tract.
The current strain of H5N1 has already mutated to infect mammals, and a few genetic changes could be all it takes for the virus to spread more efficiently to humansor, worse, between them. Were at the highest risk of the virus since the early 2000s, when a different strain of H5N1 led to numerous deadly human infections in East and Southeast Asia, Webby said. Not because the virus itself is necessarily more infectious but because it is spreading among so many different animals, and especially mammalsgiving it more opportunities than ever to find a way to replicate in humans. But, again, despite all that transmissionall those chances for the virus to mutate into something that can reliably sicken humansit hasnt yet. That could absolutely continue to be the norm, David Topham, a flu expert at the University of Rochester Medical Center, told me.
The status quo is still pretty troubling. New cases of bird flu keep popping up in herds across the country, raising fears that it might never be eradicated from cattle. The most likely scenario, Webby said, is that this virus will become endemic in birds and dairy cowsa constant presence, regularly causing outbreaks. Right now, infections in poultry tend to align with the migration of wild birds; if cows are constantly infected, chicken outbreaks could become more frequent.
Nothing about endemicity would be good for humans. The consequences would be diminished, but not eliminated. Farmworkers may continue to periodically fall sick, Guthmiller said. The cost of regular animal outbreaks would be exorbitant. The USDA has already allocated more than $2 billion to address surges among poultry and livestock, which includes compensating farmers for animals that have been killed and eggs that have been destroyed to quell the spread.
If the virus continues to regularly sicken cows, it will have even more opportunities to mutate in a way that could allow it to more easily infect humans. In infected cows, virus particles are mostly found in their udders; the virus is thought to spread between the animals through contaminated milking equipment. Research released last week, which has not yet been peer reviewed, indicates that cows can be infected by aerosolized virus; if they can spread the virus through their exhalations and sneezes, they could become infected merely by breathing the same air.
H5N1 is restlessit will continue trying to infect new hosts. Given enough opportunities to mutate, the virus will do so. Its like playing the lottery, Topham said. Were giving this virus a lot of tickets. H5N1 may also be able to combine with flu viruses from different animals. If cows, chickens, and other animalssay, pigs, which arent affected by the current outbreakon the same farm all have different versions of the flu, thats your mixing vessel right there, Topham said. The H1N1 virus that caused the 2009 swine-flu outbreak, for example, was a mix of flu viruses from pigs, humans, and birds.
There is one other possible futurethe best-case scenario, which unfortunately is also the least likely. The virus possibly could disappear, Webby said. This would partly depend on eradicating it from cows, which he believes is plausible with human intervention and herd immunity. But eliminating the virus in birdsthe main animals that get bird flu and spread itis largely out of human control. H5N1 is particularly lethal in birds, with a mortality rate of up to 100 percent for some species; if it somehow kills enough of them, Guthmiller said, it very well could just fizzle out. Dumb luck, as Webby put it, might still prevail.
But a supercharged bird virus with a taste for infecting mammals is not the kind of thing that should be left up to chance. It is fortunate that only 11 farmworkers have been infectedas far as we know. Tools to curtail the spread of bird flu are available, but theyre not being used, or used appropriately. Personal protective equipment is helpful when worn correctly, but doing so isnt feasible when it involves wearing respirators and Tyvek suits in temperatures that reach 104 degrees Fahrenheit. Unlike many other countries, the U.S. does not vaccinate chickens against H5N1, in part because its expensive to do. And cost is also why only 60 farmworkers have been tested for bird flu, giving an imperfect window into the viruss spread. Its going to be a lot more costly to deal with another pandemic than to deal with immunizing our farms, Topham said.
Americas response has been painfully shortsighted, and the country is paying the price: Had bird flu been kept in check earlier, it might never have made it into cows, and might never have developed the mutations that allow it to flirt so closely with human-to-human transmission. At this point, bird flus future has no good optionsonly one thats bad, another thats abysmal, and one that relies on nothing but dumb luck.
A scientific team has confirmed the most feared scenario: the highly pathogenic avian influenza virus, which has been spreading through U.S. dairy farms for months, has managed to jump from cow to cow, and from cattle to cats and a raccoon. The researchers, from Cornell University, have issued a warning. Efficient and sustained mammal-to-mammal transmission is unprecedented. It is worrisome because it may cause the virus to adapt, enhancing its infectivity and transmissibility to other species, including people, the researchers note in their study, which was published urgently Wednesday in the journal Nature. The authors call for strict measures to prevent transmission to cows and to reduce the risk of a pandemic in humans.
The world is currently experiencing the biggest avian influenza crisis ever known. A subtype of the H5N1 virus, designated 2.3.4.4b, emerged in 2021 in wild birds and has since killed hundreds of millions of birds worldwide. The World Health Organization still considers the risk to the public to be low, although its records show that the H5N1 virus has jumped from birds to at least 889 people since 2003, killing 463 of them (52%). Scientists worst nightmare is that a virus with such lethality will mutate and become capable of human-to-human transmission, which has not happened so far.
Cornell researchers, led by Brazilian virologist Diego Diel, have observed that this subtype of the virus has a strong ability to infect udder cells and concentrate in milk, although it also appears in the lungs of cows. Scientists speculate that the pathogen may be transmitted via the respiratory or oral route, but they also suspect that it could enter through the teat orifice from contaminated soil or milking machines. As for the cats and the raccoon, the hypothesis is that they became infected by drinking contaminated milk. Two months ago, an experiment on mice showed that raw milk may contain viruses capable of transmitting the disease.
Virologist Elisa Prez is concerned about what is happening in the U.S., where 168 affected herds in 13 states have been identified since the first case was detected in a cow on March 25. It is very worrying, because it implies that cows constitute a new reservoir of avian influenza at least of this particular genotype and that they can act as a source of infection for other species, both birds and mammals. This is something that had never been observed before with this virus, since the only natural reservoir of avian influenza was birds, says the expert, from the Animal Health Research Center in Madrid. Infected cows may display symptoms such as reduced appetite, digestive disorders, respiratory problems and lower milk production. So far, there have only been outbreaks among cattle in the United States.
The nine farms tested in the study are in Texas, New Mexico, Ohio, and Kansas. They are outdoor farms, where wild birds have contact with dairy cows, both directly and indirectly, through contaminated feed or water. The first affected farms are on a route commonly used by migratory birds to cross North America.
On January 25, a scientific team found the B3.13 version of the 2.3.4.4b subtype of the H5N1 virus, the root of the unprecedented outbreaks in dairy cattle, in a Canadian goose in Wyoming. The analysis of the complete genome of the virus in cows has not detected mutations that favor the jump to humans.
Prez stresses that cows on a farm in Ohio became infected after the arrival of asymptomatic cattle from another facility in Texas. This confirms that apparently healthy cows can transmit the virus. That is, not all cows develop clinical symptomatology after infection. This has very important implications for surveillance systems, explains the virologist. With these data, it is clear that we should not only carry out passive surveillance (testing only samples from cows with symptoms), but it is also essential to include active surveillance programs, such as, for example, testing tank milk on all cattle farms, as will be the case in Colorado, one of the states most severely affected by avian influenza in cows.
American epidemiologist Maria van Kerkhove, director of the emerging diseases unit of the World Health Organization, declared two months ago that Covid-19 would not be the last pandemic we will deal with in our lifetimes. Diel points to H5N1 from his laboratory at Cornell University. It is difficult to predict which virus will be next but given the propensity of influenza viruses to cause pandemics, it is very important to keep a close eye on the H5N1 situation in dairy cattle, he explains to EL PAS.
The first outbreak that set off alarm bells worldwide occurred at a mink farm in Spain. In autumn 2022, dead seagulls and gannets appeared on Galician beaches. In early October, American mink began to die of hemorrhagic pneumonia at a fur farm in Carral, outside A Corua. Mortality in the outbreak exceeded 4% in just seven days. A study led by biologist Montserrat Agero, of the Ministry of Agricultures Central Veterinary Laboratory, suggested in January 2023 that the avian flu virus had jumped from wild birds to mink, mutated on the farm, and been transmitted from mammal to mammal. Early last year, the mass death of sea lions from bird flu in Peru suggested that the virus might be jumping between mammals in the wild. Dutch veterinarian Thijs Kuiken, of the Erasmus University Medical Center in Rotterdam, then posed a question in EL PAS: If it occurs in minks and sea lions, why wont it occur in humans?
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Ten people in the state have contracted the virus so far, according to the Colorado Department of Public Health and Environment.
WELD COUNTY, Colo. More cases of avian flu in humans have been reported by Colorado health officials.
Three bird flu cases were reported at a second chicken farm in Weld County, the Colorado Department of Public Health and Environment (CDPHE) said in a release.
CDPHE said the cases were discovered after more testing was ordered for the poultry workers when another worker at the farm was confirmed to be positive. The workers who contracted the virus were culling birds that were positive for avian flu, CDPHE said.This is the second chicken farm in Weld County to have confirmed human cases of avian flu.
In all, 10 human cases of avian flu have been confirmed so far. Nine cases came from the two poultry farms, and one case came from a dairy farm.
The health department did not release information on the workers' conditions. In previous cases, the other positive patients had mild symptoms including pink eye and common respiratory infection symptoms, but none were hospitalized.
CDPHE announced they are launching a new online dashboard to track avian flu cases in humans. The dashboard will be updated by 4 p.m. on Tuesdays and Thursdays.
The dashboard will include:
The Colorado Department of Agriculture posts data on avian flu activity in poultry and dairy cattle weekly or as cases are confirmed.
The Colorado Department of Agriculture this week stepped up efforts to stop a runaway outbreak of bird flu cases on dairy farms by issuing an order requiring testing for the virus on all commercial cow dairies licensed by the state.
But, separately, new information about the bird flu virus that infected a Colorado farmworker provides reassuring evidence that the virus remains a low risk to human health.
The state has seen at least 51 cases of bird flu on dairy farms since April, meaning nearly half of all commercial dairies in Colorado have been affected. Of those cases, 30 have happened in the past 30 days.
Colorados outbreak continues to surge even as others have dwindled nationwide no other state has seen more than four cases in the past 30 days, and some major dairy-producing states like Wisconsin and California have never reported any cases.
In issuing the order, state veterinarian Dr. Maggie Baldwin said the virus, while not causing deaths of many cattle, has still been a devastating disruption to Colorados dairy industry resulting in quarantines and loss of milk production.
We have been navigating this challenging, novel outbreak of HPAI in dairy operations for nearly three months in Colorado and have not been able to curb the spread of disease at this point, Baldwin said in a statement, using a shorthand term for the virus, which is also known as highly pathogenic avian influenza.
The order does not apply to farms that produce raw milk, which are not regulated by the state. Pasteurization kills the virus in milk sold in stores, but raw milk is unpasteurized, meaning there is the potential for it to contain live virus.
Baldwin noted that, as the dairy outbreaks rage on, they are also generating spillover cases in other animals. Most notably, Colorado has begun seeing infections again in commercial poultry operations.
There have been two major, confirmed outbreaks at egg-laying operations in Weld County, while a third, suspected outbreak is also under investigation. Those outbreaks have resulted in the culling of more than 3.2 million chickens just in July, according to the Department of Agriculture.
Colorado has now seen 33 commercial poultry flocks affected since 2022, with more than 6.3 million domestic birds culled.
Then theres the human toll. One of those poultry outbreaks led to an unprecedented cluster of cases among workers who were doing the culling. Six workers were confirmed positive for bird flu, though their symptoms were relatively mild and none required hospitalization.
Meanwhile, the Colorado Department of Public Health and Environment announced Thursday that it has identified three new human cases of bird flu these tied to culling operations at a different poultry farm. The workers, likewise, have mild symptoms and have been offered antiviral drugs for treatment.
Including the new cases, the state has now identified 11 out of the 14 human cases nationwide since 2022, placing Colorado at the center of the nations bird flu epidemic. And the burst of human infections in Colorado has raised questions about whether the flu virus has mutated to make it more capable of infecting people.
But a new CDC analysis eases those concerns. The CDC took a virus sample from one of the Colorado poultry workers and sequenced its genome.
Among the findings:
So, to recap: Nothing about the Colorado case suggests the bird flu virus has become better able to infect people, hurt people or spread to other people. The CDC said the analysis supports CDCs conclusion that the human health risk currently remains low.
The CDC also reported some more good news last week: Blood tests of Michigan dairy workers were boring.
Michigans public health department conducted what is known as a seroprevalence study of workers with known exposures to infected cows. The goal was to see if workers who showed no symptoms of bird flu actually had antibodies against the virus. If they did, it would suggest that they had been silently infected and that human cases might be more common than known.
Instead, the results from every nonsymptomatic worker tested came back clean no antibodies against bird flu.
This is an important finding, the CDC wrote in a weekly update, because it suggests that asymptomatic infections in people are not occurring.
That means the risk remains primarily to farmworkers who have direct contact with infected animals. And that puts the focus on efforts to provide information to farms and to ensure workers have access to and are able to wear protective equipment.
Ongoing cooperation is key to supporting workers health and safety, protecting animal health and welfare, and minimizing the spread of the virus, Kate Greenberg, Colorados commissioner of agriculture, said in a statement.
Based on facts, either observed and verified directly by the reporter, or reported and verified from knowledgeable sources.
