How mysterious pneumonia disease in China is different from SARS

The outbreak in Wuhan, a city of 11 million, seems serious. Dozens of people have been hospitalized, a few in serious condition, since the first patient had symptoms on December 12. Two cases have been confirmed outside of China, in Thailand and Japan; both involved travelers arriving from Wuhan. On the other hand, at least six patients in Wuhan were discharged and only one death was reported. The death occurred on January 9 in a patient with serious underlying medical conditions. There have been no cases of health workers who become infected, which supports the first findings that the disease is probably not transmitted from person to person. That reduces the potential for it to generate an outbreak like SARS, which began in China and spread throughout the world, infecting thousands of people.

2. What are the symptoms?

Mainly fever, with some patients experiencing fatigue, dry cough and shortness of breath. Chest x-rays have shown invasive lesions of both lungs, said the World Health Organization. However, so far only cases that require hospitalization have been reported. It is possible that other people have been infected and have not experienced symptoms, or only mild ones.

The Chinese authorities identified a new coronavirus (not seen before) in one of the pneumonia patients hospitalized in Wuhan after gene sequencing. WHO has labeled the new virus 2019-nCoV. Genomic data were made available to the public in mid-January, which allowed scientists outside China to study their genetic footprint to get clues about where and how it could have arisen. A report prepared for the International Journal of Infectious Diseases found that it is at least 70% similar in genetic makeup to the SARS virus, but “seems clinically milder” in terms of severity, mortality rate and transmissibility.

4. How do people get infected?

Like the source of the virus, the way it spreads is unknown. WHO quoted the Chinese authorities as saying that it is not easily transmitted between people. Researchers have focused on the wholesale seafood market in Wuhan, where most infected people worked or bought frequently. The market has been closed since New Year’s Day and no additional cases have been detected in China since January 3. Outside of China, a man was hospitalized in Japan on January 10, but released five days later. He had developed a fever while in Wuhan and then tested positive for 2019-nCoV. The Thai case involved a woman who lived in Wuhan who traveled with a tourist group to Bangkok on January 8, three days after experiencing symptoms. Thai authorities confirmed that she was infected. None of the patients had visited the market linked to most other cases. That raised the possibility that the pathogen is lurking more widely in the city, a worrying outlook before the Lunar New Year (January 25 of this year), which stimulates purchases of frantic groceries, which sometimes include exotic foods.

5. What is a coronavirus?

There is a large family of them, and some cause less serious diseases, others more. Some transmit easily from person to person, while others do not. The role of coronaviruses in cases of severe pneumonia is increasingly recognized. WHO says periodically new ones emerge in different areas worldwide, and several known coronaviruses circulate in animals that have not infected humans.

6. Why does it take so long to identify?

May vary. HIV, for example, was not discovered as the cause of AIDS for years. In the case of SARS, many of China’s best doctors were initially adamant in treating pneumonia caused by chlamydia, a sexually transmitted bacterium. China fired its then health minister, Zhang Wenkang, for mishandling that crisis. Wuhan hosts China’s first maximum biocontainment laboratory, built in 2015 to investigate the most dangerous pathogens on the planet, so it is well placed for the current outbreak. The scientists there have probably been evaluating a number of possible culprits. In mid-January, specialists from outside of mainland China were invited to Wuhan to share information.

Authorities in Wuhan say they are providing the best possible medical care. Patients have been isolated to prevent any possible spread. Health officials also search, evaluate and control the people with whom patients had contact, and look for current and past cases that may have been treated at medical institutions throughout the city. Environmental samples were taken from the closed market for analysis.

There are some, although narrow, parallel. Both emerged in China. In the case of SARS, it is believed that it has spread indirectly from a “wildlife reservoir,” which is believed to be bats, to humans through masks of masked palms and other species in live animal markets. The Wuhan outbreak has also been linked to live animal markets, which makes it possible for the infectious agent to have an animal origin. Communicable diseases from animals to humans, sometimes referred to as “zoonoses,” comprise a large percentage of all newly identified infectious diseases.

–With the help of Dong Lyu.

To contact the journalist in this story: Jason Gale in Melbourne at [email protected]

To contact the editors responsible for this story: Michael Patterson at [email protected], Paul Geitner, Jeff Sutherland

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