With one case in Thailand, the WHO is warning about the possibility of broader spread.
The mysterious virus causing dozens of people to fall sick with pneumonia in China has now popped up in Thailand, the first case of international spread since the outbreak was announced on December 31.
The patient — a 61-year-old woman from China — had traveled to Bangkok from Wuhan, the mainland Chinese city of 19 million that’s currently the center of the outbreak, according to the World Health Organization (WHO) and the Bangkok Post. Sixteen people who sat near the woman on her flight have so far tested negative for the virus, and the woman is now recovering at the Bamrasnaradura Infectious Diseases Institute outside Bangkok.
What’s most significant about this case is that the woman never visited the Wuhan food market that’s been linked to the outbreak, according to a WHO spokesperson. Instead, she “reported a history of visiting [other] local markets in Wuhan on a regular basis prior to the onset of illness on January 5, 2020.” This could mean the new virus has the potential to spread from person to person, instead of just from an animal carrying the virus to humans, as health authorities have been suggesting. Or it may suggest there are animals at other markets shedding the virus — and that it may have already moved beyond Wuhan.
The spokesperson added that while there’s “no clear evidence of human-to-human transmission,” the precise way the virus is spreading “has not yet been determined and human-to-human transmission is always a concern when patients have respiratory symptoms.”
For now, the outbreak centers on a single food market in Wuhan, the capital of Hubei, one of China’s most populous provinces. Health officials in Wuhan have reported that the patients with the virus so far were “mainly business staff and purchasers” at the Huanan South China Seafood Market, where vendors peddle seafood as well as animals such as birds and rabbits. This suggested that the new virus had spread to humans from one of the animals there.
With the first case in Thailand, the WHO warned about the possibility of broader spread and said it was considering organizing an emergency committee meeting. If such a meeting is called, a panel of independent experts would discuss whether the outbreak is dire enough to constitute a “public health emergency of international concern,” a rare designation the WHO gives to diseases that pose a global threat.
China is sharing information about the outbreak fast — a contrast to SARS
Because health authorities are dealing with a new virus, the picture of this outbreak — and its seriousness — is shifting rapidly.
The outbreak in Wuhan was only declared on December 31. By January 9, the state broadcaster China Central Television reported that 15 of the people who had become ill tested positive for the new virus. By January 11, scientists in China shared the genetic sequence of the new virus and the WHO applauded China’s efforts. “WHO is reassured of the quality of the ongoing investigations and the response measures implemented in Wuhan, and the commitment to share information regularly,” the agency said in a statement.
This was also a contrast to the SARS outbreak of 2003, when China was heavily criticized for withholding information about the outbreak for too long.
But other aspects of the outbreak bear a startling resemblance to SARS, which also involved a then-new virus when it was discovered in 2003. The virus jumped from civet cats — a food delicacy in China — to humans, and went on to spread to two dozen countries. It eventually killed 774 people and infected more than 8,000.
The one patient death “marks this virus as a significant concern”
To date, authorities in Wuhan have reported 41 patients with the novel coronavirus infection. Of the 41, seven are severely ill, and two have been discharged from the hospital. One patient — a 61-year-old man with underlying health problems, including chronic liver disease — died on January 9. The man went into the hospital with respiratory failure and severe pneumonia. He had bought food from the Wuhan market regularly and tested positive for the new virus.
The leading hypothesis is that the disease is the result of a new coronavirus, a member of the same family of viruses as SARS.
Coronaviruses attack the respiratory system and can target the cells deep within the lungs. “There are tons of coronaviruses,” said Vincent Munster, an emerging viral diseases researcher at the National Institute of Allergy and Infectious Diseases.
Most infect mammals, including bats. Two of the six that are known to infect humans, SARS and MERS, can cause severe pneumonia and even death. The rest lead to milder symptoms, like a common cold.
In the current outbreak, the main symptoms reported are fever followed by difficulty breathing, the WHO said. In chest X-rays, patients appear to have lesions in both lungs. According to the Bangkok Post, the patient in Thailand had neither fever nor respiratory symptoms, and might be discharged in a few days.
The death of one patient “marks this virus as a significant concern,” said Peter Daszak, the president of EcoHealth Alliance, a US global health research organization working in China.
Big questions remain
Researchers will need to confirm that this new virus is without a doubt the driver of the outbreak, said Marion Koopmans, who studies emerging infectious diseases as director of the virology department at Erasmus Medical Center in Rotterdam. They’ll then need to figure out the range of illness the virus causes in the confirmed cases.
“If [the new virus] is indeed the likely cause, and seeded at the market, a key question is how transmissible this is,” Koopmans said. Viruses that spill over from animals may not be very transmissible “if they sit deep in the lungs and are not shed easily,” she added. That would mean, Munster said, “the epidemic potential of this virus might still be limited.”
But, again, the Thailand case suggests the potential for human-to-human spread. And it’s possible, Daszak said, that the virus was incubating in patients for a couple of weeks, and that the secondary cases — from people who were directly exposed to the animal carrying the virus — are only now going to start popping up.
If that’s the case, “the scope of this outbreak expands massively,” he added. “We already have 40-plus cases in China and one is traveling. I don’t understand why there are so many cases if there’s no human-to-human transmission.”
Health officials would also need to find out which animal is spreading the virus to humans — the “natural reservoir” of the virus — and how the virus made the jump, and then make sure that animal is contained.
“We don’t know where the virus came from,” Daszak said. “We don’t know the geographic origin of the wildlife reservoir. And it’s now known to be lethal.”
At the moment, the WHO is not recommending any measures for travelers, nor is it advising against travel or trade restrictions on China, even on the cusp of China’s Lunar New Year holiday, during which hundreds of millions of people are expected to travel. (A new study found the top travel destinations out of Wuhan are Asian megacities, including Bangkok, Hong Kong, Tokyo, and Taipei.) The market that’s been linked to the outbreak has been closed for disinfection, and health investigators are following 739 close contacts of the patients, including 419 medical staff, to see if they develop symptoms. Officials in Wuhan say there have been no new cases there since January 3.
Author: Julia Belluz
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