Federal officials have confirmed that three California dairy herds have suffered outbreaks of H5N1 bird flu, due most likely to the transportation of cattle and not exposure to diseased birds.

Health officials announced last week that they suspected cows at three Central Valley dairies had contracted the illness, and were awaiting testing for confirmation. On Tuesday, officials said those tests revealed that the strain of virus that infected California herds was nearly identical to that found in Colorado dairy herds — suggesting the infections were the result of interstate transfer of cattle.

The B3.13 genetic sequence found in the infected cows was clearly the result of “anthropogenic movement; essentially zero chance it was an independent spill from wild birds into these dairies,” said Bryan Richards, the Emerging Disease Coordinator at the U.S. Geological Survey’s National Wildlife Health Center. “So, if anyone is trying to blame wild birds: Nope!”

In a statement from the California Department of Food and Agriculture, officials said there were no confirmed human cases of H5N1 bird flu in the state, and neither the U.S. Centers for Disease Control and Prevention nor state officials see this development as a significant public health threat; the risk to humans is considered low.

“The primary concern is for dairy workers who come into close contact with infected dairy cows,” said officials in the statement. Four cases of human infection from dairy have been reported in other states, including Texas, Colorado and Michigan.

Officials also said the state’s supply of milk and dairy foods is not affected. Contaminated milk is not permitted to be sold and pasteurization inactivates the virus, “so there is no cause for concern for consumers from” pasteurized milk or dairy items.

“We have been preparing for this eventuality since earlier this year when [hightly pathogenic avian influenza] detections were confirmed at dairy farms in other states,” said CDFA Secretary Karen Ross. “Our extensive experience with HPAI in poultry has given us ample preparation and expertise to address this incident, with workers’ health and public health as our top priorities.”

Hoping to stop or slow the spread of the virus, the U.S. Department of Agriculture in April limited the movement of some interstate cattle transfers, mandating that lactating dairy cattle get tested for bird flu before any transfer, and that livestock owners report any positive cases before moving the animals across state lines.

Large-scale cattle movement is standard practice among U.S. dairy farms, and many send days-old calves away to be raised at farms that specialize in rearing calves. Once the calves are grown, the females are generally sent back to the dairy where they were raised — or to another dairy — while males are sent to feeding lots, veal farms or straight to slaughter.

In 2022, research from a team out of Texas Tech University showed that 1 in 10 dairy-born calves were raised off-site at these “calf ranches.” That rose to almost 5 in 10 when researchers looked at farms that had more than 500 lactating cows.

The researchers noted that these operations are often located hundreds, if not thousands, of miles from the dairy farms where the animals were born. “It is not uncommon to see operations feeding over 20,000 pre-weaned calves in the Central Great Plains and West regions,” wrote the authors.

This large-scale transfer of cattle is one of many biosecurity weak spots that observers and critics of the dairy industry say is contributing to the spread of the disease.

According to a USDA map, 197 herds have been affected in 14 states since March, when the virus was first reported in U.S. dairy cattle.

In an interview from July, Maurice Pitesky — an associate professor with a research focus on poultry health and food-safety epidemiology at UC Davis — noted that the dairy industry “is uniquely susceptible to the potential for disease transmission from a single dairy” in part because of these cattle transfers.

Commercial poultry farms, which have been contending with avian flu for decades, have the advantage of being closed systems in that most farms have physical barriers such as fences and walls that keep wildlife, including waterfowl, away from the commercial birds. In contrast, dairies are open to the outside environment and in many cases — such as the flushing of dairy stalls with lagoon water — purposely introduce potentially infected water (from dairy lagoons where waterfowl roost) into their facilities.

“When you go on to a poultry facility, you have to fill out paperwork that says you haven’t touched any other birds for 48-72 hours, because they’re so concerned about disease transmission,” he said, underscoring the biosecurity of these operations.

Surveillance of the virus is also complicated by the fact that H5N1 infected cows show only subtle signs of infection — lethargy, decreased milk production, etc. Poultry, on the other hand, die.

Without mandating on-site testing, or milk-pool testing — in which farmers test samples of the milk they’ve pooled from their cows — it’s hard to know where the virus is.

For now, California dairy farmers are working to keep an eye on their cows for signs of illness. And according to Michael Payne, a researcher and outreach coordinator at the Western Institute for Food Safety and Security at UC Davis, state and local health officials are working to understand and perhaps limit the movement of the disease.

Payne said the state has quarantined the three herds where infections have been confirmed. And all animal movement on or off those farms now requires permits.

“There are no lactating cows leaving those herds right now,” he said, adding that “any younger stock that need to go, or animals that need to go to slaughter, or dead animals that need to be moved … all of that is being permitted through the creation of a pretty extensive biosecurity program that is being overseen and developed with California CDFA employees, veterinarians, veterinary medical officers.”

He said he’s been on the phone for days fielding calls from producers and helping them follow best practices as they watch for signs of infection.

The location of the herds has not been divulged. The federal government provides county data on infected poultry, but only statewide figures for dairy.

“We do not tend to share that because sometimes there are only one or two dairies in a certain county, and due to privacy concerns, we tend to refer folks to the state,” said Will Clement, a spokesman for the USDA. “If the state department of ag wants to share that information, that is their purview. But we don’t want to out anybody, if you will, in any specific region,” he said.

A spokesman for the state department of agriculture said his agency is not naming specific counties.

With the new COVID-19 vaccinations for the 2024–25 season arriving in California and across the nation, an important question arises: When is the best time to get the shot?

The U.S. Centers for Disease Control and Prevention says September and October are generally the best times for most people to get the COVID immunization.

But which month is better for your particular situation? Should you rush to get the shot now, considering the high levels of COVID circulating in California? Or should you wait till closer to Halloween in hopes that doing so will extend more robust protection against infection through Christmas and into the New Year?

And what about people who got infected recently or got the old immunization formula a couple of months ago?

Providers in California began administering COVID-19 immunizations using the latest formulation this week. Appointments are available at CVS, Walgreens, Rite Aid, Ralphs, Vons, Albertsons, Pavilions and Safeway stores. Kaiser Permanente expects to begin making vaccines available by mid-September and possibly earlier in some locations. Sutter Health is also aiming for a mid-September rollout.

The CDC recommends that everyone 6 months old and older get the updated COVID-19 vaccination, which was authorized for distribution by the U.S. Food and Drug Administration last week.

Here are some factors to consider:

The case for October

The head of the CDC suggested that the most important decision is not when to get the vaccination, but just getting it.

“The important part is getting it done,” CDC Director Mandy Cohen said at a briefing. “If September, from a calendar perspective, works better for folks, great. October gets you closer to the winter season. But the important part is getting it done.”

Dr. Peter Chin-Hong, a UC San Francisco infectious disease expert, makes the case for an October dose.

Getting the COVID-19 vaccine now or in October will offer good protection against severe disease for at least a year, he said. But the best protection against infection is roughly six to eight weeks after getting vaccinated — although that window can be wider if the vaccine is a close match to circulating subvariants, Chin-Hong said.

“To me, the sweet spot is always October,” he said, as it’s closer to the peak of the late fall and winter respiratory virus season, as well as major holidays like Thanksgiving, Christmas and New Year’s. Based on wastewater data during the last two winters, COVID peaked in California and nationally either the last week of December or the first week of January.

The case for September

But Dr. Elizabeth Hudson, regional chief of infectious diseases for Kaiser Permanente Southern California, suggested that people get the vaccine as soon as they can.

“The way that COVID is looking now — with just the sheer volume of cases — this is not a year that you want to wait,” Hudson said. “As soon as you are able to get the vaccine, you should get it.”

COVID-19 continues to circulate at a very high level nationally and in California. Depending on the region, health officials are “potentially seeing some indication of a plateauing of the summer increase in COVID-19,” said Dr. Demetre Daskalakis, who heads the CDC’s National Center for Immunization and Respiratory Diseases. Still, “we’re not out of the woods yet,” he added. Trends won’t be clear until there are a few weeks of sustained declines, and that hasn’t happened yet.

Not only is the hyperinfectious KP.3.1.1 subvariant gaining dominance nationwide, doctors also are closely watching a new upstart subvariant, XEC, that has been getting attention in Europe.

Dr. Peter Marks, the FDA’s vaccine chief, said in an Aug. 23 briefing that he has scheduled his vaccine appointment.

“Getting vaccinated now probably gives you the maximum amount of protection that you can get against what’s currently circulating, and that will last for several months, at least,” he said.

What about seniors and immunocompromised people?

Chin-Hong said there are certain people he would urge to get the COVID-19 vaccination as soon as possible. That includes those who are older or immunocompromised and haven’t been vaccinated in more than a year. Those groups are at highest risk for being hospitalized with COVID, Chin-Hong said.

“I would love them to get protected,” he said.

Dr. Eric Topol, director of the Scripps Research Translational Institute in San Diego, offered some questions people should ask themselves to determine whether they should get vaccinated now versus in October.

“How long has it been since you had a booster? If it’s been more than six months, you know your immunity has waned,” Topol said. “How is your risk? Are you older — greater than 65? Are you immunocompromised? Are you somebody with a lot of comorbidities? You might want to just go now [if so], because you’re vulnerable.”

“For people at risk, I don’t think it’s a good idea to delay,” Topol said.

Another question: Are you getting vaccinated to reduce your chance of long COVID? “Because the studies in totality suggest up to a 50% reduction of long COVID” following vaccination, he said. “In fact, that’s people in their 30s and 40s that are at the highest risk for long COVID after a mild infection, and a lot of people tend to forget that issue.”

Another consideration is whether you are about to go on a trip or planning an unmissable event or experience.

“Right now, if they want to prevent infection, it’s a good time to get something because it’s so closely matched to what’s going around,” Chin-Hong said of the new vaccine.

But if you’re doing lower-risk activities and would rather save your time of enhanced protection against infection for the fall and winter holidays, some doctors say it’s reasonable to wait until October to get vaccinated

Already, it appears that XEC, the new subvariant detected in Europe, may be a contender for a late autumn and winter COVID wave, Topol said.

“Waiting a couple extra months so you’re closer to whatever the next wave/wavelet is like, that’s a reasonable plan,” Topol said. But protecting against infection is less important than protecting against severe illness, which the vaccine is very good at doing.

Topol said he’s getting his COVID-19 vaccination Friday, in part because he’s going on a cross-country trip and he’ll be indoors with crowds and unable to avoid exposure to the virus, he said.

Masking remains important to avoid infection, but there are some situations where people may not be able to wear a mask all the time.

Overall, though, there isn’t any one simple answer as to whether September or October is better for timing your COVID vaccination. “It’s really up to the person,” Topol said.

What about people who had COVID-19 recently?

After infection, people may consider waiting three months to get the latest COVID vaccination, according to the CDC. In terms of when to start counting the three-month period, Hudson said a good rule of thumb would be from when your symptoms began or, if asymptomatic, when you were diagnosed.

Part of that reason, the CDC says, is that “the risk of getting COVID-19 is less likely in the weeks to months following a SARS-CoV-2 infection,” using the formal name of the virus that causes COVID.

Besides potentially being able to benefit from some natural immunity, “there are also some studies that show that waiting for a few months after you’ve had COVID to get your COVID vaccine may increase your overall level of protection,” Hudson said.

But this advice applies only to people who are at lower risk for COVID and its complications, Hudson added.

For those at higher risk — such as seniors 65 and older and those who are immunocompromised — or anyone in frequent contact with people at higher risk, “they should get their vaccine as soon as they’re feeling better,” she said.

What about people who got the old vaccine this summer?

A number of people who weren’t up to date on their vaccinations may have gotten the old vaccine formula — originally released in September 2023 — over the summer. Those people should wait two months before getting the newer shot, Hudson said.

As more species are pushed to the brink of extinction, conservationists are responding to our biodiversity crisis in new and sometimes controversial ways. One such novel approach could be described as the mammoth in the room: “de-extinction” technology that has the potential to protect and restore species on the brink of extinction and, more provocatively, those that disappeared from the planet long ago.

We can avoid such innovation and the controversy that comes with it. But the reality is that many milestone moments in conservation have been contentious.

Take the California condor, whose population was down to 22 known individuals in 1982. At the time, taking all the animals out of the wild for a captive breeding program sparked outrage among conservation professionals and in local communities. Today, however, thanks to those efforts and subsequent reintroductions of the birds into the wild, their population exceeds 500. Now captive breeding programs are regularly used to maintain and restore a variety of threatened species.

Or consider conservationists’ difficult decision in 1995 to relocate eight female mountain lions from Texas to infuse new genes into the population of Florida panthers, a subspecies of the puma. Only about 30 Florida panthers were left at the time, and inbreeding had rendered them susceptible to disease and other health problems. Although this genetic rescue effort was highly controversial at the time, it was also very successful, decreasing the effects of inbreeding and allowing the population to steadily grow. Today about 200 adult panthers live in southwest Florida, and the intervention is regarded as a model.

The use of assisted reproductive technology such as artificial insemination and in vitro fertilization to bolster dwindling species has been a more recent subject of debate within the conservation community. But since these tools were introduced, they have become standard among zoos’ “insurance” populations of threatened species and in captive breeding programs aimed at reintroducing species into the wild.

Our organizations, the biotechnology company Colossal Biosciences and the conservation group Re:wild, recently announced a partnership to use de-extinction technology to protect and restore species on the brink of extinction. It is a powerful collaboration between an organization with extensive experience in wildlife and ecosystem conservation and a company that is using gene editing and genetic engineering technology to make extinction a thing of the past.

Both Re:wild and Colossal want to save species that are going extinct now. But at the heart of Colossal’s mission is a belief that the science to restore and recover species on the brink can be accelerated by moonshot projects such as reviving the mammoth or the dodo. This focus on de-extinction, or bringing back extinct species, is understandably a subject of vigorous debate.

So it’s no wonder that our partnership caught some in the conservation community by surprise. Even internally, it took lots of thoughtful and nuanced discussion — involving often passionate and sometimes seemingly insurmountable differences — to align around shared goals.

In the end, even though Re:wild has reservations about whether the woolly mammoth and other extinct species should be returned to Earth, the organization will advise on the feasibility of such reintroductions because of the projects’ potential to generate technology that could save hundreds of critically endangered species. We will work together to study the advantages, disadvantages and feasibility of each reintroduction, working with local interests and a cross-section of the conservation community. With the world’s sixth great extinction event upon us, we need every available tool to prevent extinctions and accelerate species restoration.

The conservation community has recovered species from the brink of extinction — some of which were down to a few individuals — but every one of those recoveries has been hard-fought. We will be able to restore critically endangered species much more quickly by combining Colossal’s technology with proven approaches such as conservation breeding programs, translocations of endangered species populations, assisted reproductive technology, biobanking of threatened species’ tissues and cells, and genetic rescue.

We are already seeing the benefits of Colossal’s technology for threatened species. The tools and techniques developed for every effort to bring a species back from extinction will also benefit closely related species that still live.

The woolly mammoth project, for instance, has sequenced the genomes of both the Asian elephant and the African elephant; has developed induced pluripotent stem cells with the ability to differentiate into other types of elephant cells; and is accelerating a cure for the deadly elephant herpes virus. Many extant marsupials will likewise benefit from the technology Colossal is developing to bring back the thylacine, an extinct carnivorous marsupial also known as the Tasmanian tiger or Tasmanian wolf. That includes the development of artificial pouches and synthetic milk, which will enable expanded conservation breeding programs and reintroduction efforts.

We’re also using or planning to use this technology to protect and restore northern white rhinos, Sumatran rhinos, pink pigeons, Tasmanian devils, northern quolls (a small carnivorous marsupial) and many other species.

Not everyone agrees that a headline-grabbing de-extinction of the woolly mammoth would be beneficial to our planet. But it’s hard to dismiss the project’s capacity to create tools and technologies that can prevent countless species from going extinct in the first place.

Our partnership is also allowing us to tap into new sources of conservation funding that would not be available without the interest that de-extinction generates. Even though it will always be cheaper and easier to save a species from extinction than to bring it back, we still need more resources to combat the biodiversity crisis.

Conservation is not easy, and the extinction crisis has no single solution. With an estimated 12% of bird species, 26% of mammals, 31% of sharks and rays, 36% of reef-building corals and 41% of amphibians at risk, we need to consider every tool we have to secure the future of our planet and all the life on it. We look forward to the day de-extinction technology is commonly used to restore endangered species and we’re considering the next conservation moonshot.

Matt James is Colossal’s chief animal officer. Barney Long is Re:wild’s senior director of conservation strategies.