It was recently forwarded by the World Health Organization that the list of countries that have reported Tamiflu-resistant swine flu viruses has two new names: China and Singapore.

According to Charles Penn, a scientist with the Geneva-based agency, the WHO has also been informally made aware about the discovery of a small number of other Tamiflu-resistant viruses. However, he did not specify as to where these cases have been reported.

A formal notification of seven cases of Tamiflu resistance, among people with the pandemic flu, has been received by the WHO, which include three from Japan and one each from Canada, Denmark, Hong Kong and Singapore.

Till now, no formal report has been filed by Chinese authorities; however, it has alerted the WHO of the initial laboratory finding through the Global Influenza Surveillance Network.

It was specified by Penn that there is no proof till date that Tamiflu-resistant viruses are spreading.

He concluded: "The reported cases to date have been isolated, with no connections among them and no sign that the infected people passed resistant viruses to their contacts."