Virologist: Global disease needs global understanding

"It is a very important area of study establishing this origin, but it takes time, and needs to really weigh up all the evidence," said Stephen Winchester, a consultant virologist at Berkshire and Surrey Pathology Services in the UK.

"The more understanding and knowledge of these variants (we have), the more we know about how these epidemics could occur... it's all useful evidence," he said in a recent interview with Xinhua.