Thursday, August 13, 2009

WHO update on the spread of H1N1

Great update from WHO on the global spread and incidence of novel H1N1. Here's the most important exceprt,

"This season, pandemic H1N1 has been the predominant influenza virus in nearly all of the temperate regions of Southern Hemisphere, with South Africa being a notable exception. Australia and countries in the southern part of South America experienced rapid increases in cases of pandemic influenza early in their winter season. These same areas are now starting to report decreases in the numbers of people seeking care and being admitted to hospital. Although the virus is still circulating in these areas as it moves into areas not affected earlier, the overall national trends are downward. South Africa, in contrast, experienced an early influenza season with a seasonal subtype, influenza A (H3N2). As the influenza season in South Africa reached its peak in early to mid June and began to decline, pandemic influenza H1N1 appeared and has now become the dominant subtype seen there as well...

In the temperate areas of the northern hemisphere which experienced early outbreaks of pandemic H1N1 influenza, including countries in North America and Europe, the virus continues to spread to new areas and cause intense local outbreaks. However, the overall national trend in cases is downward in the Americas...

Tropical regions of the world, which typically experience year round transmission of influenza viruses with peak transmission at different and often multiple times in a year, are now seeing increases in cases, for example in tropical areas of Central and South America and in South and South East Asia.

In summary, the overall picture of transmission globally is one of declining transmission in the temperate regions of the Southern Hemisphere with the exception of southern Africa."

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