When was swine flu declared a pandemic

Here's a look back on the swine flu pandemic with eight key facts from the CDC : 1. The WHO declared the swine flu outbreak a pandemic on June 11, WHO declared an end to the pandemic on Aug. Featured Whitepapers. It became known as swine flu because it's similar to flu viruses that affect pigs.

It spread rapidly from country to country because it was a new type of flu virus that few young people were immune to. Overall, the outbreak was not as serious as originally predicted, largely because many older people were already immune to it. Most cases in the UK were relatively mild, although there were some serious cases. A year later, when the WHO declared an end to the pandemic, between , and , people had died. A massive global vaccine effort led by the US helped end the pandemic, but the H1N1 virus is still with us.

Every year it circulates as a seasonal flu, causing sickness, hospitalisation and deaths. Scientists across the globe monitor both H1N1 and other swine influenzas to better understand how these diseases start and to figure out how to stop the next virus before it becomes a pandemic. But stopping a virus is complex work, made all the harder by human activity: from the way we produce our food to the way we travel. To better understand what we're up against, a massive collaboration has been taking place across 2, European pig farms, sampling more than 18, individual pigs.

On the northeastern cusp of Germany, where the land meets the Baltic Sea, lies the tiny Isle of Riems. Access is via a causeway, and not by accident. Modern biosecurity measures mean that virus institutes can be based almost anywhere, but in , after too many diseases were finding their way from his laboratory into the local community, Loeffler decided it was best to set up on an island.

It takes 30 minutes or so to circumnavigate the island on foot, passing large square buildings housing the laboratories, animal experiment facilities and animal enclosures, which are home to pigs, chickens, cattle and a wild boar breeding zone. At the furthest tip of the lot lies the duck enclosure, where teams monitor bird flu patterns and newly emerging virus strains, by attracting wild birds to stop in on their migratory journeys.

Thousands of cranes, wild ducks and geese pass through this area each year. Martin Beer has worked here for 20 years. He is one of the scientists who began rapidly creating and testing vaccinations when the swine flu pandemic hit, and now is head of the Institute of Diagnostic Virology.

It's his team that has been carrying out the massive sampling exercise of Europe's pigs. So far, they have found four influenza viruses circulating which already have some of what they call the "building blocks" of a pandemic. They are viruses that can infect humans, have the potential to spread from human to human, and for which there is no vaccination or innate immunity. Currently, none of the viruses discovered have all the necessary building blocks. But if any one of these viruses manages to adapt, the chance of another pandemic is substantial.

The team also found that the prevalence of these viruses in pigs is increasing over time. This is a lot," Beer says. Pigs, like humans, are susceptible to more viruses when they are young because they have not yet had time to build up the antibodies needed to fight them. In Europe's intense pork production system, pigs live to be just six months old before they are killed.

That's not yet old enough to fight off most influenza viruses, so "you have a lot of highly susceptible pigs", says Beer. More than million a year , in fact. But Europe has advantages that make it less prone to human disease than some parts of the world.

It's a wealthy continent with good healthcare systems in many of its countries, it's home to some of the world's leading scientists, and it generally has a temperate climate.

Traditionally, humans developed farming systems suitable for our environments. But that has changed. With the surge in population has come a surge in demand for protein sources.

Europe is trying to produce more pork, faster than ever, and that demand is creating new diseases. He says there's a connection between the way Europe is producing protein and the viruses they're seeing. Now we have holdings with and 20, sows. It's a gross increase in the farm size. This is something that changes the epidemiology of the influenza viruses," he says. Twenty years ago, if a new virus cropped up in a small pig farm it would probably have dissipated rapidly, without many hosts to infect.

Not any more, according to Harder. An influenza virus, once introduced, is perpetuated constantly. You will find it over years, all year round," he says. Though the flu pandemic primarily affected children and young and middle-aged adults, the impact of the H1N1 pdm09 virus on the global population during the first year was less severe than that of previous pandemics.

Estimates of pandemic influenza mortality ranged from 0. It is estimated that 0. However, H1N1 pdm09 virus continues to circulate as a seasonal flu virus, and cause illness, hospitalization, and deaths worldwide every year. Skip directly to site content Skip directly to page options Skip directly to A-Z link.

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