An international team of scientists, including a prominent researcher at the Wuhan Institute of Virology, has analyzed all known coronaviruses in Chinese bats and used genetic analysis to trace the likely origin of the novel coronavirus to horseshoe bats.
In their report, posted online Sunday, they also point to the great variety of these viruses in southern and southwestern China and urge closer monitoring of bat viruses in the area and greater efforts to change human behavior as ways of decreasing the chances of future pandemics.
The research was supported by a U.S. grant to EcoHealth Alliance, a New York-based nonprofit, that was recently canceled by the National Institutes of Health. The grant, for more than $3 million, was well on its way to renewal, and the sudden reversal prompted an outcry in the scientific community.
Thirty-one U.S. scientific societies signed a letter of protest on May 20 to the N.I.H., and 77 Nobel laureates sent another letter to the N.I.H. and the Department of Health and Human Services seeking an investigation of the grant denial. The Nobelists said the cancellation appeared to be based on politics rather than a consideration of scientific merit.
The report on the research, which has been accepted by the journal Nature Communications, was posted on the BioRxiv (pronounced bio-archive), where scientific research is often released before publication.
The report gives a glimpse of the work the grant had supported.
The researchers, mostly Chinese and American, conducted an exhaustive search for and analysis of coronaviruses in bats, with an eye to identifying hot spots for potential spillovers of these viruses into humans, and resulting disease outbreaks.
The genetic evidence that the virus originated in bats was already overwhelming. Horseshoe bats, in particular, were considered likely hosts because other spillover diseases, like the SARS outbreak in 2003, came from viruses that originated in these bats, members of the genus Rhinolophus.
None of the bat viruses are close enough to the novel coronavirus to suggest that it jumped from bats to humans. The immediate progenitor of the new virus has not been found, and may have been present in bats or another animal. Pangolins were initially suspected, although more recent analysis of pangolin coronaviruses suggests that although they probably have played a part in the new virus’s evolution, there is no evidence that they were the immediate source.
The new research includes an analysis of bat and viral evolution that strongly supports the suspected origin of the virus in horseshoe bats, but isn’t definitive, largely because a vast amount about such viruses remains unknown.
The report also adds detail to what scientists know of coronaviruses in bats, how they have evolved and what kind of threat they pose. Renewal of the grant would have supported a continuation of this work.
N.I.H. canceled the grant shortly after President Trump was asked at a news conference about money erroneously described as going to the Wuhan institute. That lab has been the target of conspiracy theorists who promote the idea that the novel coronavirus was made in a lab. Scientists and U.S. intelligence agencies agree that the overwhelming likelihood is that the virus evolved in nature.
Richard Ebright, a microbiologist and biosafety expert at Rutgers University, has argued that there could have been an accidental leak of a naturally evolved virus that was present in the lab, and that lab safety should be investigated. Many scientists view the leak scenario as unlikely given the many opportunities for infection in the wildlife trade, markets and farming.
There is also no reported evidence that the new virus was ever present at the Wuhan Institute of Virology. It was first discovered after numerous human cases appeared in late December, most in people with connections to a wet market in Wuhan.
Zheng-Li Shi, the director of the Center for Emerging Infectious Diseases at the institute, known for work tracking down the source of the original SARS virus in bats and identifying SARS-CoV-2, as the novel coronavirus is known, is one of the authors of the new paper, along with Peter Daszak, the president of EcoHealth Alliance.
The researchers collected oral and rectal swabs, as well as fecal pellets from bats in caves across China from 2010 to 2015, and used genetic sequencing to derive 781 partial sequences of the viruses. They compared these to sequence information already documented in computer databases on bat and pangolin coronaviruses.
Frequently Asked Questions and Advice
Updated June 1, 2020
How do we start exercising again without hurting ourselves after months of lockdown?
Exercise researchers and physicians have some blunt advice for those of us aiming to return to regular exercise now: Start slowly and then rev up your workouts, also slowly. American adults tended to be about 12 percent less active after the stay-at-home mandates began in March than they were in January. But there are steps you can take to ease your way back into regular exercise safely. First, “start at no more than 50 percent of the exercise you were doing before Covid,” says Dr. Monica Rho, the chief of musculoskeletal medicine at the Shirley Ryan AbilityLab in Chicago. Thread in some preparatory squats, too, she advises. “When you haven’t been exercising, you lose muscle mass.” Expect some muscle twinges after these preliminary, post-lockdown sessions, especially a day or two later. But sudden or increasing pain during exercise is a clarion call to stop and return home.
My state is reopening. Is it safe to go out?
States are reopening bit by bit. This means that more public spaces are available for use and more and more businesses are being allowed to open again. The federal government is largely leaving the decision up to states, and some state leaders are leaving the decision up to local authorities. Even if you aren’t being told to stay at home, it’s still a good idea to limit trips outside and your interaction with other people.
What’s the risk of catching coronavirus from a surface?
Touching contaminated objects and then infecting ourselves with the germs is not typically how the virus spreads. But it can happen. A number of studies of flu, rhinovirus, coronavirus and other microbes have shown that respiratory illnesses, including the new coronavirus, can spread by touching contaminated surfaces, particularly in places like day care centers, offices and hospitals. But a long chain of events has to happen for the disease to spread that way. The best way to protect yourself from coronavirus — whether it’s surface transmission or close human contact — is still social distancing, washing your hands, not touching your face and wearing masks.
What are the symptoms of coronavirus?
Common symptoms include fever, a dry cough, fatigue and difficulty breathing or shortness of breath. Some of these symptoms overlap with those of the flu, making detection difficult, but runny noses and stuffy sinuses are less common. The C.D.C. has also added chills, muscle pain, sore throat, headache and a new loss of the sense of taste or smell as symptoms to look out for. Most people fall ill five to seven days after exposure, but symptoms may appear in as few as two days or as many as 14 days.
How can I protect myself while flying?
If air travel is unavoidable, there are some steps you can take to protect yourself. Most important: Wash your hands often, and stop touching your face. If possible, choose a window seat. A study from Emory University found that during flu season, the safest place to sit on a plane is by a window, as people sitting in window seats had less contact with potentially sick people. Disinfect hard surfaces. When you get to your seat and your hands are clean, use disinfecting wipes to clean the hard surfaces at your seat like the head and arm rest, the seatbelt buckle, the remote, screen, seat back pocket and the tray table. If the seat is hard and nonporous or leather or pleather, you can wipe that down, too. (Using wipes on upholstered seats could lead to a wet seat and spreading of germs rather than killing them.)
How many people have lost their jobs due to coronavirus in the U.S.?
More than 40 million people — the equivalent of 1 in 4 U.S. workers — have filed for unemployment benefits since the pandemic took hold. One in five who were working in February reported losing a job or being furloughed in March or the beginning of April, data from a Federal Reserve survey released on May 14 showed, and that pain was highly concentrated among low earners. Fully 39 percent of former workers living in a household earning $40,000 or less lost work, compared with 13 percent in those making more than $100,000, a Fed official said.
Can I go to the park?
Yes, but make sure you keep six feet of distance between you and people who don’t live in your home. Even if you just hang out in a park, rather than go for a jog or a walk, getting some fresh air, and hopefully sunshine, is a good idea.
How do I take my temperature?
Taking one’s temperature to look for signs of fever is not as easy as it sounds, as “normal” temperature numbers can vary, but generally, keep an eye out for a temperature of 100.5 degrees Fahrenheit or higher. If you don’t have a thermometer (they can be pricey these days), there are other ways to figure out if you have a fever, or are at risk of Covid-19 complications.
Should I wear a mask?
The C.D.C. has recommended that all Americans wear cloth masks if they go out in public. This is a shift in federal guidance reflecting new concerns that the coronavirus is being spread by infected people who have no symptoms. Until now, the C.D.C., like the W.H.O., has advised that ordinary people don’t need to wear masks unless they are sick and coughing. Part of the reason was to preserve medical-grade masks for health care workers who desperately need them at a time when they are in continuously short supply. Masks don’t replace hand washing and social distancing.
What should I do if I feel sick?
If you’ve been exposed to the coronavirus or think you have, and have a fever or symptoms like a cough or difficulty breathing, call a doctor. They should give you advice on whether you should be tested, how to get tested, and how to seek medical treatment without potentially infecting or exposing others.
How do I get tested?
If you’re sick and you think you’ve been exposed to the new coronavirus, the C.D.C. recommends that you call your healthcare provider and explain your symptoms and fears. They will decide if you need to be tested. Keep in mind that there’s a chance — because of a lack of testing kits or because you’re asymptomatic, for instance — you won’t be able to get tested.
How can I help?
Charity Navigator, which evaluates charities using a numbers-based system, has a running list of nonprofits working in communities affected by the outbreak. You can give blood through the American Red Cross, and World Central Kitchen has stepped in to distribute meals in major cities.
They found evidence that the novel coronavirus may have evolved in Yunnan Province, but could not rule out an origin elsewhere in Southeast Asia outside China.
The family of bats that included the horseshoe genus, Rhinolophus, seems to have originated in China tens of millions of years ago. They have a long history of co-evolution with coronaviruses, which the report shows commonly jump from one bat species to another.
Dr. Daszak said that the region where China, Laos, Vietnam and Myanmar converge may be “the real hot spot for these viruses.”
He said the region was characterized not only by bat and coronavirus diversity, but by urbanization, population growth and intense poultry and livestock farming, all of which could lead to viruses jumping from one species to another, and to the spread of human disease.
Not only bats should be monitored, Dr. Daszak said, but humans. “People are farming wildlife all across Southern China, tens of thousands of people involved in the industry, they should be getting regular tests, not just for Covid-19, but for what other viruses they are picking up.”
He acknowledged that such an effort would be very costly, but said that compared to the cost of a pandemic, “You’re definitely getting a good return on investment.”