A previously unknown virus, first reported in the Chinese city of Wuhan on Dec. 31, is seriously worrying global health experts. The World Health Organization announced Monday that it was convening an emergency meeting on the virus, which is a coronavirus, a species common in animals that occasionally leaps to humans. In China, past cases of viruses passing from animals to humans have been relatively common thanks to close contact with domestic animals like chickens, as well as the consumption of wild animals such as civet cats, and sometimes because population and resource pressures have pushed people deeper into previously untouched forests and jungles in the south.
The most notable of these in recent years was SARS, a coronavirus first reported in 2003 that eventually killed over 800 people and infected around 8,000; the government was widely blamed for covering up the spread of SARS—short for “severe acute respiratory syndrome”—until Jiang Yanyong, a retired surgeon, raised the alarm (and was briefly imprisoned as a result before eventually being hailed as a hero).
Is this a deadly disease? How fast is it spreading?
It’s hard to tell, because the information being released by the Chinese government is questionable. Wuhan itself is a city of 11 million people, and within China, the virus is confirmed to have reached major metropolises such as Beijing and Shanghai, while it’s also traveled as far south as Shenzhen, which borders Hong Kong. Outside of China, Japan, Thailand, and South Korea have all recorded cases—all Chinese travelers. While it was initially claimed to be only the result of animal-to-human transmission, doctors have just confirmed human-to-human transmission; 14 health care workers have also been reported as infected.
The virus causes pneumonia, resulting in difficulty breathing. As of Wednesday evening EST, the number of reported dead has risen to nine. The majority of victims, though, had only mild symptoms, and some have already been discharged.
It’s always an open question how bad a new virus could get. Modern disease control methods have improved dramatically since the 1918-19 influenza outbreak killed more people than World War I—and the global population is healthier and more resistant. In the United States, the Centers for Disease Control and Prevention says the odds of the virus reaching the country are low. Right now, the main worries are in China itself—especially the government’s handling of the cases.