MEXICO CITY (AFP) - The first case of swine flu was confirmed in Asia on Friday as health experts said a vaccine should be ready in a matter of months and Mexico said the virus was not as aggressive as originally feared. Confirmation by the authorities in Hong Kong that a traveller from Mexico tested positive for A(H1N1) flu virus saw an entire hotel quarantined and sent shivers through the territory which was at the centre of the 2003 SARS crisis. Denmark also joined the list of affected countries while more cases emerged of victims contracting the virus even though they had not travelled to Mexico. The Mexican government meanwhile raised its confirmed toll to 15 dead and 328 people infected as the country began a five-day shutdown to halt the viruss spread. Health Minister Jose Angel Cordova said the new count did not represent new cases coming in but rather testing and analysis of a backlog of probable cases in the epicentre of the crisis. Fortunately the virus is not so aggressive - its not a case of avian flu, which had a mortality rate of nearly 70pc, Cordova told reporters. He said the A(H1N1) flu virus, while far more contagious than avian flu, was easily treated with anti-viral medicine if treatment is given from the first day. Mexican authorities meanwhile cancelled the traditional gatherings of workers to celebrate May Day, as the country went into a five-day holiday they hoped would minimise public contact and slow the viral spread down even more. Restaurants, bars, tourist sites and other public venues remained closed in the capital and elsewhere. US health officials say they have confirmed 141 infections in 19 states, while a total of 14 countries have now confirmed cases. Hong Kong Chief Executive Donald Tsang said the 25-year-old Mexican man who had tested positive had arrived in the Chinese territory on Thursday from Mexico via Shanghai. Among the latest cases revealed in Germany was that of a nurse who had treated a patient with the disease, but had not been to Mexico. The nurse subsequently recovered. Scottish authorities also confirmed the first case of swine flu in Britain involving someone who had not recently travelled to Mexico. Poland and Austria also reported new suspected swine flu cases, including that of a 29-year-old Pole hospitalised in Warsaw after returning from the United States, where he spent time in a jail with Mexican inmates. Authorities across the world have tightened travel restrictions and taken other measures to keep the virus from spreading. Singapore invoked public health orders not used since the 2003 SARS crisis, ordering anyone arriving from Mexico to be quarantined for one week. Argentina and Cuba have both suspended flights to Mexico. However the United Nations reversed advice it had given to staff on Thursday that they should postpone travel to flu-hit countries. Although it was initially dubbed swine flu, the WHO is now officially referring to it as Influenza A(H1N1), in part because the virus is not spread by contact with pigs but transmitted from person to person. The UN health body meanwhile said it was examining its response to the outbreak in Mexico following accusations that it had reacted too slowly, but defended its response. There are cases of influenza all the time, but once we knew that this illness was cause by a new influenza virus... we moved into operation within a matter of hours, WHO spokesman Thomas Abrahams told journalists.