H1N1 FLU BREAKING NEWS: Cases reach 2,500, Mexico's severe cases, concern about viral mixing, holding at phase 5

May 8, 2009

The World Health Organization (WHO) listed a global total of 2,500 confirmed cases of swine influenza H1N1 in 25 countries today. That total included 1,204 cases in Mexico, 896 cases in the United States (yesterday's number), 214 in Canada, 88 in Spain, and 34 in the United Kingdom. The death toll remains at 44, including 42 in Mexico and 2 in the United States. [WHO update 22]

The US swine flu case count jumped to 1,639 confirmed cases in 43 states as of this morning, an increase of 743 from yesterday's total of 896 cases, according to the Centers for Disease Control and Prevention (CDC). The death toll remains at 2. Illinois had the most cases with 392, followed by Wisconsin, 240, New York, 174, Alabama, 131, and California, 107. At a news briefing, CDC Director Dr. Richard Besser said 57 US patients—3.5% of the total—were hospitalized. He said the nation has about another 850 probable cases. [CDC H1N1 flu page

WHO experts held a conference call yesterday with Mexican officials to discuss clinical findings in the patients who died from severe swine flu infections, Sylvie Briand, acting director of the WHO's Global Influenza Program, said today at a media briefing. Mexican health officials have identified two high-risk groups: previously healthy young people who deteriorated rapidly with acute pneumonia and people with chronic health conditions such as cardiovascular disease or tuberculosis. Briand said viral pneumonia has played a role in the deaths, but bacterial pneumonia has been less of a factor, unlike in other pandemics. Authorities have found that causes of death are typically respiratory failure or organ failure.

A leading flu expert is worried that the swine flu virus could combine with the H5N1 avian flu virus to produce a new, highly contagious and lethal strain, the Associated Press (AP) reported today. "My great worry is that when this H1N1 virus gets into the epicenters for H5N1 in Indonesia, Egypt and China, we may have real problems," virologist Robert Webster told the AP. Malik Peiris, a flu expert at Hong Kong University, said the more immediate concern is that the swine flu virus could mix with regular flu viruses.

The WHO still has found no evidence of community transmission of the swine flu virus outside North America, which would trigger the move from a pandemic phase 5 to phase 6, Sylvie Briand, a WHO influenza expert, told reporters today. Most new cases outside North America represent imported infections linked to travel or infections in travelers' close contacts.

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