Thirty countries have officially reported 4,694 laboratory confirmed human cases of A/H1N1 flu infection, including 53 deaths, the World Health Organization (WHO) said in a latest update on Monday.

Mexico, the epicenter of the outbreak, has reported 1,626 human cases of infection, including 48 deaths, the UN agency said.

Meanwhile, the United States has reported 2,532 human cases, including three deaths. Canada has reported 284 cases, including one death. Costa Rica has reported eight cases, also including one death.

The following countries have reported laboratory confirmed human infections with no deaths: Argentina (1), Australia (1), Austria (1), Brazil (8), China (2, comprising 1 in Hong Kong and 1 in the mainland), Colombia (3), Denmark (1), El Salvador (4), France (13), Germany (11), Guatemala (1), Ireland (1), Israel (7), Italy (9), Japan (4), the Netherlands (3), New Zealand (7), Norway (2), Panama (15), Poland (1), Portugal (1), Republic of Korea (3), Spain (95), Sweden (2), Switzerland (1) and Britain (47).

The WHO's pandemic alert level is currently at phase 5, which means a flu pandemic is imminent.

The agency has said that it still has no plan to raise the alert level to phase 6, the highest level which means a global pandemic is underway, as there is still no strong evidence showing community-level human-to-human transmission of the new virus has occurred in regions outside North America.

The WHO said, however, that it was closely monitoring the situation in European countries such as Spain and Britain, which have reported the largest numbers of cases outside North America.

(Xinhua News Agency May 11, 2009)