Meanwhile, the virus is continuing its spread through the Northern Hemisphere this summer -- even though flu viruses normally don't spread well in hot weather -- and its effect is escalating in the southern half of the globe, where it is the traditional winter flu season. Within the next few days, the WHO will suggest that countries with large outbreaks of H1N1, or swine, flu move away from laboratory confirmation of cases and toward larger, national indicators of disease, such as numbers of influenza-like symptoms and pneumonia cases, Dr. Keiji Fukuda, WHO assistant director-general said Tuesday in a telephone news conference. The large number of cases in such countries is overwhelming laboratories and making it 'very hard to keep up' with testing, he said. The new guidelines will 'ease the burden on laboratories,' he said. In most countries with large outbreaks of the virus, 95 percent or more of all flu cases are now caused by the new virus. 'In countries with no cases, we will continue to recommend that people be tested so the presence of the new virus can be confirmed,' he said. 'In all countries, we will continue to stress testing for unusual cases, clusters, unusually severe cases and new symptoms.' Soon there will likely be very few countries with no cases. The most recent figures reported to the WHO indicate more than 98,000 laboratory-confirmed cases in 120 countries and 440 deaths, but officials estimate there are actually 10 to 100 times as many actual infections. The most recent figures for the U.S. indicate 33,902 laboratory-confirmed cases and 170 deaths, but officials from the Centers for Disease Control and Prevention have estimated that more than 1 million Americans have been infected by the virus. In the last two weeks, health officials have identified three patients with a virus resistant to Tamiflu, known generically as oseltamivir -- one each in Denmark, Japan and Hong Kong. The cases in Denmark and Japan occurred in patients who had been taking the drug prophylactically; the Hong Kong case involved a girl who flew in from San Francisco and had never been given oseltamivir, suggesting she contracted a resistant virus. Viruses from all three patients displayed the same mutation producing the resistance, and officials believe it is a spontaneous mutation, not a recombination with seasonal viruses, many of which are resistant to the drug. All three viruses were susceptible to Relenza, known generically as zanamivir. The WHO is not particularly concerned about the mutations, he said, because there is no evidence that the resistant virus is being spread. 'The single most important point, at this time, is that we are not recommending any clinical changes to . . . treating patients,' Fukuda said. The agency continues to recommend prophylactic treatment of those exposed to people with a known case of H1N1 flu. Also within the last couple of weeks, the WHO has assembled a team of experts to name the virus formally, which is now officially pandemic A(H1N1) 09 virus. The committee rejected a place name for fear of stigmatizing the country of origin and also rejected an animal name because it raises fears about food, Fukuda said. Unlike seasonal flu viruses, the H1N1 virus is continuing to spread largely unabated through the summer months in the Northern Hemisphere. Outside the U.S. and Mexico, the greatest impact has been seen in Britain. Last week, that country's health minister said he expected 100,000 new cases every day for the foreseeable future. The virus is also increasing its spread through the Southern Hemisphere, which is at the beginning of its flu season. Hardest hit is Argentina, with 2,800 confirmed cases and a death toll that doubled in the last week to 60, the third-highest toll after the U.S. and Mexico. Chile has had more than 8,000 confirmed cases and 18 deaths. Australia is also suffering, with more than 6,300 confirmed cases and 13 deaths. Africa has been the last continent to suffer an outbreak of the virus, but its presence has now been confirmed in 12 countries on that continent, Fukuda said. 