There is no evidence whatever to support the claims that China is the source of the bird flu virus, and there is no clear answer yet as to where the virus originated, World Health Organization (WHO) spokeswoman Fadela Chaib said.

More than 20 WHO labs are currently conducting tests on samples of the bird flu virus collected from the Asian countries, Chaib told a news conference here on Friday.

She also advised that staff workers on poultry farms strengthen sterilization measures, including wearing protective clothing and masks of N95-type, and that those exposed to poultry wash their hands promptly.

WHO looks forward to working closely with China 's Ministry of Health to prevent the spread of the highly pathogenic avian influenza, Chaib added.

(Xinhua News Agency January 31, 2004)