The pneumonia outbreak was first reported in Wuhan City, central China's Hubei Province, in December 2019. Experts have attributed the outbreak to a novel coronavirus that has since spread across China and abroad.

Here is what we know so far:

- Confirmed cases: 5,997 in China, 63 abroad

- Deaths: 132 

- Human-to-human transmission confirmed

- Health experts say the virus has the potential to mutate

- 30 cities and provinces have launched a Level I emergency response, while Hong Kong declared its "highest" emergency response.