As a viral pneumonia continues to spread, an expert on human outbreaks that originate in animals shares what we know so far about 2019n-CoV
The emergence of a new virus that causes potentially fatal pneumonia led to China shutting down travel in and out of Wuhan, one of its largest cities, as the country prepared to celebrate Lunar New Year. The virus—known as 2019-nCoV—is related to others known to cause deadly respiratory disease.
The first cases of the viral illness were initially reported to be sickened people who had worked or shopped at a live-animal market in the city in the Hubei province in central China. However, new information has since been published in the scientific journal The Lancet that casts some doubt on this assumption—with three of the four earliest known cases having no connection to the seafood market.
Either way, the new virus quickly spread to other parts of China and has since been diagnosed in people in the United States and thirteen other countries in Asia, Australia, and Europe. As of January 26, 2019-nCoV had infected more than 2,700 people and killed at least eighty.
For many, the situation raises fears of another pandemic similar to that seen with severe acute respiratory syndrome (SARS), another coronavirus. In 2002-2003, SARS spread to more than two dozen countries, infecting more than 8,000 people and killing 774. With reports of Chinese hospitals being overwhelmed by suspected cases of 2019-nCoV, China has announced plans to build a new 1,000-bed prefab hospital to treat infected patients within six days, similar to how it did for SARS.
Jonathan Epstein, V02, MPH02, the vice president for science and outreach at EcoHealth Alliance, a science-based nonprofit in New York, studies coronaviruses such as SARS and Middle East respiratory syndrome (MERS), along with other diseases transmitted between animals and people that have emerged in Asia and Africa.
Named for their physical structure—which, when looked at under an electron microscope, appears round with a crown of spikes—coronaviruses are found in many different mammals and birds. (Cats, for example, have a coronavirus that causes feline infectious peritonitis).
“Before SARS was discovered, there were only four known human coronaviruses, and they typically caused mild respiratory disease,” said Epstein. “That changed when SARS and MERS coronaviruses emerged and caused human fatalities.”
Tufts Now: Where did this new coronavirus come from?
Jonathan Epstein: This new virus is one of a group of coronaviruses related to SARS. Genetically, 2019-nCoV shares about 86 percent of its entire genome with SARS. So it is a distinct virus, but related.
It has recently come to light that some of the earliest known cases may not have been related to that Wuhan seafood market at all, suggesting that this virus may have been transmitted to people from animals elsewhere.
Which animals do you suspect are responsible?
In the SARS outbreak, bats ultimately were shown to be the natural source of that coronavirus—investigative work that EcoHealth Alliance and I were directly involved in. Other wild mammals were infected with SARS from bats, likely in the markets where people were infected.
As part of research projects funded by NIH NIAID and the USAID-funded PREDICT project, EcoHealth Alliance has worked with the Wuhan Institute of Virology and other partners over the past fifteen years to screen wildlife in China for a variety of viruses, including novel coronaviruses. Our goal has been to determine which animal species might be natural reservoirs for viruses with the greatest potential to spill over into humans. As result, we’ve been able to compare 2019-nCoV with a spectrum of coronaviruses that we found circulating in bats in China. The 2019-nCoV genome is about 96 percent identical to a bat SARS-related coronavirus we’ve previously found in China.
What needs to happen now is to test the large number of banked bat samples for this new coronavirus to see whether they do or don’t carry it. This will allow us to identify exactly which species are carrying this virus—important information to prevent another jump into humans.
How worrisome is this outbreak?
In the early stages of this epidemic, the Chinese government believed that all the cases were related to exposure to animals—that it was not spreading from person to person. The evidence now clearly shows that there is indeed human-to-human transmission occurring. That’s worrisome because that’s how SARS was able to spread so fast and so far.
In this age of frequent travel, you expect to see any illnesses that are easily transmitted person-to-person—particularly respiratory diseases—spread internationally, which has already been the case in this outbreak. I don’t think anybody was surprised to see a U.S. case—a traveler from Wuhan to Washington state. There are four other confirmed cases in Texas, California, and Arizona, and these almost certainly won’t be the last.
How would you describe the response to this outbreak so far? Has it been adequate?
It cannot be overstated how quick the response has been. China has gone to great lengths to not repeat the experience of SARS. The government, universities, and scientific institutions have been as proactive, collaborative, and transparent as possible—rapidly getting information out into the public domain with regard to the number of cases, the symptoms associated with the cases, and the genetics of the virus.
As a result, there has been a flood of information that has benefited the international public health community. Researchers are taking that information and are doing analyses to compare 2019-nCoV with other coronaviruses. The World Health Organization has worked with scientists to quickly develop a diagnostic test and to distribute it for use across China and the globe. This is critically important for surveillance, so that countries are able to quickly and accurately identify cases.
Does the large jump in cases mean we have a very serious problem on our hands?
2019-nCoV has about a fourteen-day incubation. The jump in cases partly has to do with effective patient and traveler screening at hospitals and airports—thanks to the availability of a rapid diagnostic test. However, the virus also is spreading within communities, and despite the flow of information occurring, this is still a highly dynamic situation, with new information coming out all the time. We’re still learning about how how quickly and easily this virus can be transmitted among people, what proportion of infected people develop serious disease and how serious this epidemic is likely to be.
Is the timing of this outbreak during Chinese Lunar New Year festival celebrations going to make the situation a lot worse?
Everyone is worried about that. Lunar New Year is one of the largest—if not the largest—short-term mass migrations on the planet in terms of human movement. Across the globe, there are going to be millions of people traveling within China, to China, and back from China. And there’s no doubt we are going to see more spread of this virus as a result.
Interestingly though, another mass migration event occurred while we were worried about the spread of another coronavirus. Beginning in 2013, we started to realize that there was recurring transmission of the MERS coronavirus from camels to people and then person-to-person. The potential spread of MERS became a significant concern during the Hajj, when millions of Islamic pilgrims from across the world come to Saudi Arabia to visit Mecca.
Ultimately there wasn’t widespread transmission of MERS as a result of the mass movement of travelers—the expected explosion of cases never really materialized. That’s credited to Saudi Arabia’s good preparation and public awareness. China is doing what it can to limit transmission, though the circumstances are difficult given the size and mobility of the population. We will likely see an increase in transmission following Lunar New Year.
How can we prevent future outbreaks of this virus?
Although the international public-health community has responded collaboratively, quickly, and admirably to this outbreak, one of the lessons we still have to learn is the hazard of having wildlife species for sale in live-animal markets.
Even if it turns out that this virus emerged from different sources than the Wuhan seafood market, it is likely that the virus spilled over from animals somewhere along the wildlife market chain, where there is contact between bats and people, with or without other animals being involved.
There is still little information about which other species may have been involved in human transmission, which speaks to the importance of thoroughly investigating animals as part of the initial outbreak investigation. This information is critical so that policies can be targeted that reduce the risk of this happening again. As long as people continue to sell and consume wildlife in these types of intensive live animal markets, there’s going to be a risk for new viruses emerging. And as this practice is still common in China and elsewhere, we are likely to see more of these spillover events—and the consequences may be bad.
While we’d like to see humanity change its behavior to be more protective on that front, there may be some hope on the horizon in terms of vaccine development. In 2017, the Coalition for Epidemic Preparedness Innovations was created to accelerate the development of vaccines against emerging infectious diseases—and coronaviruses were among its top priorities. As a result, there are already vaccines in development with the goal of being protective against a broad spectrum of coronaviruses.
Should banning wildlife consumption be an international public-health priority?
Recognizing the risk of SARS, many cities in China have outlawed the sale of wildlife and China has banned all wildlife trade temporarily as part of this outbreak response. But people are still buying wild animals for consumption, often illegally, so we clearly have a lot of work to do to curb the demand.
We know from past experience that making a high-risk behavior illegal can simply drive it underground, making it even harder to detect zoonotic transmission at a critical, early stage of emergence. Working on multiple fronts to increase public awareness of risk and change behavior will be important parts of risk reduction.
Much of the demand for wildlife markets in China is found among older generations or in rural communities. Wildlife consumption often is tied to cultural beliefs around the perceived health benefits or social prestige of eating these wild species, so it’s going to take time for those to change. The good news is that we’ve found that younger generations in China are far less interested in eating wildlife.
However, consuming wildlife is not always just a luxury or culture preference. Sometimes there are no alternatives. In some rural areas of China and other parts of the world, people depend on eating wildlife for a reliable source of protein.
Certainly that is the case with Ebola in parts of West Africa, where the largest outbreak of Ebola in history began in 2014. The lack of livestock production in places like Liberia means that people depend on bushmeat. And that’s why there continues to be a risk of Ebola emerging there. You can’t mandate that people stop eating wildlife and expect that they actually will if there’s no alternative.
Genevieve Rajewski can be reached at email@example.com.