By Thomas H. Maugh II|July 08, 2009
As the World Health Organization prepares to recommend that most countries simply assume its flu cases are due to the novel H1N1 flu virus, officials are seeing the first signs of resistance to the commonly used antiviral drug Tamiflu -- although none that are particularly disturbing yet.
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 this morning 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% 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."
But there will probably soon 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 United States 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.
