Science
New genetic research points to Wuhan animal market as origin of COVID pandemic, study says
A new analysis of genetic material gathered from a live-animal market in Wuhan in the early weeks of the COVID-19 pandemic strengthens the case that the outbreak originated there when the coronavirus jumped from infected animals to humans, scientists said.
The findings, reported the journal Cell, do not identify any specific infected animal that brought the SARS-CoV-2 virus to a Chinese city inhabited by more than 11 million people. Nor do they definitively prove that the Huanan Seafood Wholesale Market was Ground Zero for a pandemic that has resulted in more than 7 million deaths.
But the genetic evidence shows the market met the conditions necessary to spark an outbreak and makes it increasingly difficult to explain how the coronavirus could have emerged from a laboratory, a farm or even from another of the city’s four live-animal markets, the study authors said.
“It’s like if a gorilla virus emerged in San Diego and first hit people who worked at the San Diego Zoo and lived nearby, then spread later more widely,” said Michael Worobey, an evolutionary biologist at the University of Arizona who worked on the study. “It would not be difficult to reason that it very likely came from the gorillas at the zoo.”
The root cause of the pandemic has been hotly debated since its early days. Wuhan is home to a government laboratory where scientists study coronaviruses similar to SARS-CoV-2, a fact that prompted politicians, national security experts, late-night talk show hosts and many scientists — including Worobey — to question whether the virus had leaked from the lab.
Compelling though the argument may be, hard evidence to support the leak hypothesis has been lacking. Meanwhile, more information has come to light that has persuaded scientists with expertise in relevant fields that the virus that causes COVID-19 originated in animals, just like the viruses that cause SARS, MERS and influenza.
The new results continue that trend, said Dr. Dominic Dwyer, a member of the international task force that investigated the pandemic’s origins for the World Health Organization.
“You put all of these origin hypotheses on the table, and then some of them become stronger as you get evidence,” said Dwyer, a medical virologist at the University of Sydney and Westmead Hospital in Australia who wasn’t involved in the latest work. “This paper has more evidence that supports the animal origin through the Huanan market.”
The analysis published Thursday was based on genetic data gleaned from hundreds of samples gathered in and around the Huanan market collected by researchers from the Chinese Center for Disease Control and Prevention soon after the market was shut down on Jan. 1, 2020. The Chinese team detected the coronavirus in 74 of the environmental samples they tested, according to their report last year in the journal Nature.
Worobey and his colleagues dug deeper into that data. Using two distinct gene-sequencing techniques, they looked for pieces of SARS-CoV-2 as well as for DNA from animals and people.
Then they plotted what they found on a map of the sprawling market, allowing the team to reconstruct how a few initial infections could have ballooned into a global health emergency.
Among 585 samples gathered in early January 2020, the ones that contained the coronavirus were clustered in the southwestern section of the market. That happened to be the area where wild animals were held in cages for sale.
“The market covers a couple of acres, and this comes down to one corner of the market, and to a couple of stalls,” Dwyer said. “That fits with an animal origin. If it was coming from people wandering around the market, you’d find it everywhere.”
One market stall “stood out,” the study authors wrote. It had evidence of SARS-CoV-2 in multiple places: on at least one cart, on an iron container, on the ground, and on a machine used to remove hair and feathers. The researchers dubbed it “wildlife stall A.”
Another 60 samples were taken from the market’s drainage system at the end of January 2020. The researchers found genetic evidence of the coronavirus in four of them, including one in front of wildlife stall A.
That drain was still testing positive for SARS-CoV-2 in mid-February. So were two drains downstream from it that could have been contaminated by runoff from wildlife stall A, the researchers wrote.
The samples from the stall that contained the coronavirus also contained DNA from a variety of animals, including dogs, rabbits, hoary bamboo rats, Malayan porcupines and masked palm civets. The most abundant DNA was from raccoon dogs, and some was detected in a nearby garbage cart that also tested positive for the virus.
The closest-known relatives to SARS-CoV-2 that exist in the wild are coronaviruses that circulate in horseshoe bats in southern China, Laos and Vietnam and in pangolins from southern China. But no DNA from bats or pangolins turned up in any of the Huanan market samples.
Raccoon dogs, masked palm civets, hoary bamboo rats and Malayan porcupines have transmitted bat coronaviruses before, the study authors noted. Could they have done so in Wuhan, they wondered?
Security guards stand in front of the closed Huanan Seafood Wholesale Market in Wuhan on Jan. 11, 2020.
(Noel Celis / AFP via Getty Images)
It is unclear whether bamboo rats or Malayan porcupines can be infected with SARS-CoV-2, the study authors wrote. There is no hard evidence that masked palm civets can catch the virus, but cell lines from the animals were susceptible in laboratory experiments.
Raccoon dogs, on the other hand, are known to catch and transmit SARS-CoV-2. And they were the most abundant animal in wildlife stall A.
The researchers dug into the raccoon dog DNA to see if they could have come from southern China, where they might have crossed paths with bats. They couldn’t tell, but they were able to rule out a connection to raccoon dogs that lived on fur farms in northern China.
Worobey and his colleagues also studied non-SARS-CoV-2 animal viruses that were detected in wildlife stalls to see if they offered clues about where the infected animals had come from.
A kobuvirus that infected civets in the Huanan market was closely related to a virus detected in animals sold in Sichuan and Guangxi provinces, which are closer to the territory of horseshoe bats and pangolins. And a betacoronavirus that infected bamboo rats had a close relative on a bamboo rat farm in Guangxi, one of two southern provinces where market vendors were known to have sourced the animals.
“These findings suggest some movement of infected animals from southern China to Wuhan, a trade conduit that could have also led to the emergence of SARS-CoV-2,” the study authors wrote.
Nailing this down will require more sleuthing, including field work to collect samples from animals in China, said Florence Débarre, an evolutionary biologist at the French National Centre for Scientific Research in Paris and the study’s senior author. Worobey said he plans to continue this line of inquiry.
Dwyer praised the effort to determine where the animals in the market had come from — and by extension, how the virus could have gotten to the market.
A second line of evidence also supports the hypothesis that the pandemic had a so-called zoonotic origin, scientists said.
Among the samples collected at the Huanan market on Jan. 1, 2020, the researchers were able to identify four nearly complete SARS-CoV-2 genomes. One of them was from so-called lineage A, and the other three were from the closely related lineage B.
The researchers weren’t able to tell whether those viruses were shed by animals or people, but the lineage A sample came from a stall where a worker sought medical attention in mid-December 2019. Although that was weeks before COVID-19 had been recognized as a disease, a report from the World Health Organization later described the worker as a suspected early patient.
Confirming the presence of both lineages in the market allowed the team to compare their genomes and work backward to figure out when the two strains diverged, and what their most recent common ancestor looked like. They came up with six candidates, some of them more plausible than others.
There was a 99% probability that one of the four most likely candidates was correct, and those four all had something important in common: They were “equivalent or identical” to the most recent common ancestor for the pandemic as a whole, said study leader Alexander Crits-Christoph, an independent computational microbiologist.
That’s what they would expect to find if the outbreak began at the Huanan market, the study authors said. In that scenario, an animal or animals infected with the virus arrived at the market in November or early December. The virus then spread among animals held in close quarters indoors, as well as to their human handlers. Those conditions would have given the virus the multiple chances it needed to establish itself in people and begin spreading among its new hosts in a densely populated city.
On the other hand, it’s getting more difficult to fit all of this evidence into a coherent story that has the coronavirus entering China via imported frozen food (as the Chinese government has claimed) or escaping from a virology lab with lax biosecurity protocols (as some members of the U.S. intelligence community have proposed), Dwyer said.
“We’ve had nothing added to support the lab leak or the frozen food theories,” he said. “It just continues to strengthen the animal and market hypothesis.”
Considering that the pandemic began in a city with a virology lab where scientists study coronaviruses, it makes sense to ask whether that’s more than a coincidence and to wonder whether incriminating evidence is being covered up, DéBarre said.
“Many of us were extremely open to this idea,” she said. “But then data have accumulated, and they all go in the same direction — they all point to the market.”
“In science you very rarely have final answers,” she added. “You say, ‘Given all the data we have, this looks like the most likely interpretation.’”
Science
Owners of fire-destroyed Palisades mobile home park seek to displace residents for development deal
For months, former residents of the Pacific Palisades Bowl Mobile Estates have feared the uncommunicative owners of the property would seek to displace them in favor of a more lucrative development deal after the Palisades fire destroyed the rent-controlled, roughly 170-unit mobile home park.
A confidential memorandum listing the Bowl for sale indicates the owners intend to do exactly that.
The memorandum, quietly posted on a website associated with the global commercial real estate company CBRE, says that the Palisades fire created a “blank canvas for redevelopment” at a site “ideally positioned for a transformative residential or mixed-use project.”
“I just thought, oh my god, this is so much propaganda and false advertising,” said Lisa Ross, a 33-year resident of the Bowl and a Realtor. “How can they even get away with printing this?”
Neither the current owners of the Bowl nor the real estate companies listed on the memorandum responded to requests for comment.
The memorandum describes the current single-family residential zoning as “favorable” for developers; however, the city and mobile housing law experts have painted a different picture.
Fire debris at Pacific Palisades Bowl in January 2026.
(Myung J. Chun / Los Angeles Times)
“Multifamily and mixed-use development on this site is not allowed by existing zoning and land use regulations,” Mayor Karen Bass’s office said in a statement Wednesday, adding only low density single-family housing or reconstructing the mobile home park are currently allowed. “Mayor Bass will continue taking action and [work] with residents to restore the Palisades community.”
City Councilmember Traci Park also reiterated her focus on getting the mobile home park rebuilt and allowing residents to return, with a spokesperson noting she is not entertaining the potential for any rezoning efforts from a developer.
Zoning changes typically require a city council vote and are subject to the mayor’s approval or veto.
Beyond the zoning laws, the site is also currently governed by a state law requiring cities to preserve affordable housing along the coast and a city ordinance protecting mobile home residents against sudden displacement.
Spencer Pratt, a resident of the Palisades and an outspoken supporter of the neighborhood’s mobile home community, criticized the mayor and the owners in a statement to The Times. “It’s unfortunate that Karen Bass has not advocated for mobile home residents impacted by the fire,” he said, “and that the current owner of the Bowl is ignoring good faith offers from residents to buy the property.”
The mayor’s office disputed this, noting Bass recently led a delegation of Palisadians, including mobile home owners, to Sacramento to advocate for recovery. “Mayor Bass’ priority is getting every Palisadian home — single-family homeowners, town home owners, renters, mobile home owners.”
Los Angeles Mayor Karen Bass speaks during a private ceremony outside City Hall with faith leaders, LAPD officers and city officials to commemorate the one-year anniversary of the Eaton and Palisades fires on Jan. 7, 2026.
(Allen J. Schaben / Los Angeles Times)
Bass also advocated for the federal government to include the Bowl in its debris cleanup efforts; however, the Federal Emergency Management Agency ultimately refused to include it, unlike other mobile home parks impacted by the Palisades fire. Its reasoning: It could not trust the owners to rebuild the park as affordable housing.
Court rulings over the years found the owners routinely failed to maintain the infrastructure and worked to replace the park with an “upscale resort community.” Residents also accused the owners of attempting to circumvent rent control regulations.
After the fire, it ultimately took more than 13 months to begin cleaning up the debris.
Ross said she approached the owners with independent mobile home park developers who were interested in buying the fire-destroyed lot and letting residents rebuild within months. She also approached the owners with a proposition that the former residents band together to buy the park. She heard nothing back.
“They don’t communicate,” Ross said. “It’s a feuding family. That’s also why we had so many problems with maintenance and with upgrades in the park.”
Pratt, who is running for mayor against Bass, also called on private developers like Rick Caruso to step in and save the Bowl. (Caruso’s team noted his rebuilding nonprofit is looking into how to help residents of the Bowl.)
Ross is a fan of Pratt’s proposition. “We need those kinds of people — we need Rick Caruso. That would be great,” Ross said. To sweeten the deal: “I’ll cook for him. I would make him all his favorite dishes.”
Science
A virus without a vaccine or treatment is hitting California. What you need to know
A respiratory virus that doesn’t have a vaccine or a specific treatment regimen is spreading in some parts of California — but there’s no need to sound the alarm just yet, public health officials say.
A majority of Northern California communities have seen high concentrations of human metapneumovirus, or HMPV, detected in their wastewater, according to data from the WastewaterScan Dashboard, a public database that monitors sewage to track the presence of infectious diseases.
A Los Angeles Times data analysis found the communities of Merced in the San Joaquin Valley, and Novato and Sunnyvale in the San Francisco Bay Area have seen increases in HMPV levels in their wastewater between mid-December and the end of February.
HMPV has also been detected in L.A. County, though at levels considered low to moderate at this point, data show.
While HMPV may not necessarily ring a bell, it isn’t a new virus. Its typical pattern of seasonal spread was upended by the COVID-19 pandemic, and its resurgence could signal a return to a more typical pre-coronavirus respiratory disease landscape.
Here’s what you need to know.
What is HMPV?
HMPV was first detected in 2001, according to the U.S. Centers for Disease Control and Prevention. It’s transmitted by close contact with someone who is infected or by touching a contaminated surface, said Dr. Neha Nanda, chief of infectious diseases and hospital epidemiologist for Keck Medicine of USC.
Like other respiratory illnesses, such as influenza, HMPV spreads and is more durable in colder temperatures, infectious-disease experts say.
Human metapneumovirus cases commonly start showing up in January before peaking in March or April and then tailing off in June, said Dr. Jessica August, chief of infectious diseases at Kaiser Permanente Santa Rosa.
However, as was the case with many respiratory viruses, COVID disrupted that seasonal trend.
Why are we talking about HMPV now?
Before the pandemic hit in 2020, Americans were regularly exposed to seasonal viruses like HMPV and developed a degree of natural immunity, August said.
That protection waned during the pandemic, as people stayed home or kept their distance from others. So when people resumed normal activities, they were more vulnerable to the virus. Unlike other viruses, there isn’t a vaccine for human metapneumovirus.
“That’s why after the pandemic we saw record-breaking childhood viral illnesses because we lacked the usual immunity that we had, just from lack of exposure,” August said. “All of that also led to longer viral seasons, more severe illness. But all of these things have settled down in many respects.”
In 2024, the national test positivity for HMPV peaked at 11.7% at the end of March, according to the National Respiratory and Enteric Virus Surveillance System. The following year’s peak was 7.15% in late April.
So far this year, the highest test positivity rate documented was 6.1%, reported on Feb. 21 — the most recent date for which complete data are available.
While the seasonal spread of viruses like HMPV is nothing new, people became more aware of infectious diseases and how to prevent them during the pandemic, and they’ve remained part of the public consciousness in the years since, August and Nanda said.
What are the symptoms of HMPV?
Most people won’t go to the doctor if they have HMPV because it typically causes mild, cold-like symptoms that include cough, fever, nasal congestion and sore throat.
HMPV infection can progress to:
- An asthma attack and reactive airway disease (wheezing and difficulty breathing)
- Middle ear infections behind the ear drum
- Croup, also known as “barking” cough — an infection of the vocal cords, windpipe and sometimes the larger airways in the lungs
- Bronchitis
- Fever
Anyone can contract human metapneumovirus, but those who are immunocompromised or have other underlying medical conditions are at particular risk of developing severe disease — including pneumonia. Young children and older adults are also considered higher-risk groups, Nanda said.
What is the treatment for HMPV?
There is no specified treatment protocol or antiviral medication for HMPV. However, it’s common for an infection to clear up on its own and treatment is mostly geared toward soothing symptoms, according to the American Lung Assn.
A doctor will likely send you home and tell you to rest and drink plenty of fluids, Nanda said.
If symptoms worsen, experts say you should contact your healthcare provider.
How to avoid contracting HMPV
Infectious-disease experts said the best way to avoid contracting HMPV is similar to preventing other respiratory illnesses.
The American Lung Assn.’s recommendations include:
- Wash your hands often with soap and water. If that’s not available, clean your hands with an alcohol-based hand sanitizer.
- Clean frequently touched surfaces.
- Crack open a window to improve air flow in crowded spaces.
- Avoid being around sick people if you can.
- Avoid touching your eyes, nose and mouth.
Assistant data and graphics editor Vanessa Martínez contributed to this report.
Science
After rash of overdose deaths, L.A. banned sales of kratom. Some say they lost lifeline for pain and opioid withdrawal
Nearly four months ago, Los Angeles County banned the sale of kratom, as well as 7-OH, the synthetic version of the alkaloid that is its active ingredient. The idea was to put an end to what at the time seemed like a rash of overdose deaths related to the drug.
It’s too soon to tell whether kratom-related deaths have dissipated as a result — or, really, whether there was ever actually an epidemic to begin with. But many L.A. residents had become reliant on kratom as something of a panacea for debilitating pain and opioid withdrawal symptoms, and the new rules have made it harder for them to find what they say has been a lifesaving drug.
Robert Wallace started using kratom a few years ago for his knees. For decades he had been in pain, which he says stems from his days as a physical education teacher for the Glendale Unified School District between 1989 and 1998, when he and his students primarily exercised on asphalt.
In 2004, he had arthroscopic surgery on his right knee, followed by varicose vein surgery on both legs. Over the next couple of decades, he saw pain-management specialists regularly. But the primary outcome was a growing dependence on opioid-based painkillers. “I found myself seeking doctors who would prescribe it,” he said.
He leaned on opioids when he could get them and alcohol when he couldn’t, resulting in a strain on his marriage.
When Wallace was scheduled for his first knee replacement in 2021 (he had his other knee replaced a few years later), his brother recommended he take kratom for the post-surgery pain.
It seemed to work: Wallace said he takes a quarter of a teaspoon of powdered kratom twice a day, and it lets him take charge of managing his pain without prescription painkillers and eases harsh opiate-withdrawal symptoms.
He’s one of many Angelenos frustrated by recent efforts by the county health department to limit access to the drug. “Kratom has impacted my life in only positive ways,” Wallace told The Times.
For now, Wallace is still able to get his kratom powder, called Red Bali, by ordering from a company in Florida.
However, advocates say that the county crackdown on kratom could significantly affect the ability of many Angelenos to access what they say is an affordable, safer alternative to prescription painkillers.
Kratom comes from the leaves of a tree native to Southeast Asia called Mitragyna speciosa. It has been used for hundreds of years to treat chronic pain, coughing and diarrhea as well as to boost energy — in low doses, kratom appears to act as a stimulant, though in higher doses, it can have effects more like opioids.
Though advocates note that kratom has been used in the U.S. for more than 50 years for all sorts of health applications, there is limited research that suggests kratom could have therapeutic value, and there is no scientific consensus.
Then there’s 7-OH, or 7-Hydroxymitragynine, a synthetic alkaloid derived from kratom that has similar effects and has been on the U.S. market for only about three years. However, because of its ability to bind to opioid receptors in the body, it has a higher potential for abuse than kratom.
Public health officials and advocates are divided on kratom. Some say it should be heavily regulated — and 7-OH banned altogether — while others say both should be accessible, as long as there are age limitations and proper labeling, such as with alcohol or cannabis.
In the U.S., kratom and 7-OH can be found in all sorts of forms, including powder, capsules and liquids — though it depends on exactly where you are in the country. Though the Food and Drug Administration has recommended that 7-OH be included as a Schedule 1 controlled substance under the Controlled Substances Act, that hasn’t been made official. And the plant itself remains unscheduled on the federal level.
That has left states, counties and cities to decide how to regulate the substances.
California failed to approve an Assembly bill in 2024 that would have required kratom products to be registered with the state, have labeling and warnings, and be prohibited from being sold to anyone younger than 21.
It would also have banned products containing synthetic versions of kratom alkaloids. The state Legislature is now considering another bill that basically does the same without banning 7-OH — while also limiting the amount of synthetic alkaloids in kratom and 7-OH products sold in the state.
“Until kratom and its pharmacologically active key ingredients mitragynine and 7-OH are approved for use, they will remain classified as adulterants in drugs, dietary supplements and foods,” a California Department of Public Health spokesperson previously told The Times.
On Tuesday, California Gov. Gavin Newsom announced that the state’s efforts to crack down on kratom products has resulted in the removal of more than 3,300 kratom and 7-OH products from retail stores. According to a news release from the governor’s office, there has been a 95% compliance rate from businesses in removing the products.
(Los Angeles Times photo illustration; source photos by Getty Images)
Newsom has equated these actions to the state’s efforts in 2024 to quash the sale of hemp products containing cannabinoids such as THC. Under emergency state regulations two years ago, California banned these specific hemp products and agents with the state Department of Alcoholic Beverage Control seized thousands of products statewide.
Since the beginning of 2026, there have been no reported violations of the ban on sales of such products.
“We’ve shown with illegal hemp products that when the state sets clear expectations and partners with businesses, compliance follows,” Newsom said in a statement. “This effort builds on that model — education first, enforcement where necessary — to protect Californians.”
Despite the state’s actions, the Los Angeles County Board of Supervisors is still considering whether to regulate kratom, or ban it altogether.
The county Public Health Department’s decision to ban the sale of kratom didn’t come out of nowhere. As Maral Farsi, deputy director of the California Department of Public Health, noted during a Feb. 18 state Senate hearing, the agency “identified 362 kratom-related overdose deaths in California between 2019 and 2023, with a steady increase from 38 in 2019 up to 92 in 2023.”
However, some experts say those numbers aren’t as clear-cut as they seem.
For example, a Los Angeles Times investigation found that in a number of recent L.A. County deaths that were initially thought to be caused by kratom or 7-OH, there wasn’t enough evidence to say those drugs alone caused the deaths; it might be the case that the danger is in mixing them with other substances.
Meanwhile, the actual application of this new policy seems to be piecemeal at best.
The county Public Health Department told The Times it conducted 2,696 kratom-related inspections between Nov. 10 and Jan. 27, and found 352 locations selling kratom products. The health department said the majority stopped selling kratom after those inspections; there were nine locations that ignored the warnings, and in those cases, inspectors impounded their kratom products.
But the reality is that people who need kratom will buy it on the black market, drive far enough so they get to where it’s sold legally or, like Wallace, order it online from a different state.
For now, retailers who sell kratom products are simply carrying on until they’re investigated by county health inspectors.
Ari Agalopol, a decorated pianist and piano teacher, saw her performances and classes abruptly come to a halt in 2012 after a car accident resulted in severe spinal and knee injuries.
“I tried my best to do traditional acupuncture, physical therapy and hydrocortisone shots in my spine and everything,” she said. “Finally, after nothing was working, I relegated myself to being a pain-management patient.”
She was prescribed oxycodone, and while on the medication, battled depression, anhedonia and suicidal ideation. She felt as though she were in a fog when taking oxycodone, and when it ran out, ”the pain would rear its ugly head.” Agalopol struggled to get out of bed daily and could manage teaching only five students a week.
Then, looking for alternatives to opioids, she found a Reddit thread in which people were talking up the benefits of kratom.
“I was kind of hesitant at first because there’re so many horror stories about 7-OH, but then I researched and I realized that the natural plant is not the same as 7-OH,” she said.
She went to a local shop, Authentic Kratom in Woodland Hills, and spoke to a sales associate who helped her decide which of the 47 strains of kratom it sold would best suit her needs.
Agalopol currently takes a 75-milligram dose of mitragynine, the primary alkaloid in kratom, when necessary. It has enabled her to get back to where she was before her injury: teaching 40 students a week and performing every weekend.
Agalopol believes the county hasn’t done its homework on kratom. “They’re just taking these actions because of public pressure, and public pressure is happening because of ignorance,” she said.
During the course of reporting this story, Authentic Kratom has shut down its three locations; it’s unclear if the closures are temporary. The owner of the business declined to comment on the matter.
When she heard the news of the recent closures, Agalopol was seething. She told The Times she has enough capsules of kratom for now, but when she runs out, her option will have to be Tylenol and ibuprofen, “which will slowly kill my liver.”
“Prohibition is not a public health strategy,” said Jackie Subeck, executive director of 7-Hope Alliance, a nonprofit that promotes safe and responsible access to 7-OH for consumers, at the Feb. 18 Senate hearing. “[It’s] only going to make things worse, likely resulting in an entirely new health crisis for Californians.”
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