Wuhan pneumonia outbreak: A new virus may be the cause
Web Hosting

The mysterious outbreak 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 person — a 61-year-old Chinese woman — had traveled to Thailand from Wuhan, the mainland Chinese city of 19 million that’s 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 in Nonthaburi province, just outside the country’s capital, Bangkok.

Though health officials still haven’t confirmed the precise cause of the outbreak, the leading hypothesis is that it’s the result of a new coronavirus, a member of the same family of viruses as SARS.

On 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.

Wuhan is the capital of Hubei, one of China’s most populous provinces. The outbreak has been linked to a local food market — Huanan Seafood Wholesale Market — where vendors peddle seafood as well as animals such as birds and rabbits. This could mean the new disease spread to humans from one of the animals there.

This was 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.

With the first case in Thailand, WHO said it was considering organizing an emergency 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.

One patient has died

To date, authorities in Wuhan have reported 41 patients with the novel coronavirus infection — “mainly business staff and purchasers” at the seafood market. 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 Huanan market regularly and tested positive for the new virus.

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, there are a few reassuring signs. “According to Chinese authorities, the virus in question can cause severe illness in some patients and does not transmit readily between people,” the WHO said in a statement. So far, 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.

WHO is not recommending any measures for travelers and 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, according to the South China Morning Post.

Big questions remain

But it’s still early days. 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 department of virology at Erasmus Medical Center in Rotterdam. They’ll then need to figure out what type 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.” 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.

Peter Daszak, the president of EcoHealth Alliance, a US global health research organization working in China, said the one patient death “marks this virus as a significant concern. We don’t know where the virus came from. We don’t know the geographic origin of the wildlife reservoir. And it’s now known to be lethal.”

Right now, the WHO says there’s “no clear evidence” of human-to-human transmission of the virus. But Daszak was skeptical. It’s possible, for example, that the virus was incubating in patients for a couple of weeks, and that the secondary cases are only now going to start popping up. “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,” he added. If there is, “the scope of this outbreak expands massively.”

For now, the market that’s been linked to the outbreak has been closed for disinfection, and health officials are following 739 close contacts of the patients, including 419 medical staff, to see if they develop symptoms. Health officials in Wuhan say there have been no new cases there since January 3.

Read More