(File photo: greenle.cn)

The unknown virus causing pneumonia in Wuhan, capital of central China's Hubei Province, has been preliminarily determined to be a new coronavirus, according to Xu Jianguo, a Chinese expert who led a team to evaluate the pathogen test results.

Normally, detecting the nucleic acid, genome and antibody evidence of the pathogen from the patient can be done in a short time. It will take weeks to isolate pathogens and identify pathogenicity. The development of specific drugs and vaccines against a new pathogen may cost years to complete.

Xu said the new virus needs further research and understanding.

So far, there are six known human coronaviruses. Four are common in humans and less pathogenic, generally causing only mild respiratory symptoms similar to the common cold. The other two coronaviruses-Severe Acute Respiratory Syndrome Coronavirus and Middle East Respiratory Syndrome Coronavirus, also known as SARS Coronavirus and MERS Coronavirus, can cause severe respiratory disease.

Wuhan Municipal Health Commission said that eight patients with viral pneumonia of unknown causes in Wuhan have been cured and discharged from the hospital on Wednesday. The number of pneumonia cases of unknown causes disclosed on Sunday was 59.

(Compiled by Wang Xiangyu)