Influenza

The first notable influenza outbreak of the 21st century took place when the Swine flu pandemic was declared on June 11th 2009. Thought to originally share many genes with a strain of pig (swine) flu found in North America, hence the name, it was later proved to be the result of a quadruple reassortment where 4 known strains combined - in this case, 2 strains of pig flu (found in Asia and Europe), one of bird flu (avian) and a strain endemic in humans. Although identified as Influenza Type A subtype H1N1 (responsible for Spanish flu), this assortment had never been seen before, resulting in a lack of pre-existing antibody immunity in humans.

 

Evidence points to the first reported case being a young boy in the small town of La Gloria, Veracruz, Mexico in February 2009. The disease emerged in Mexico City the following month and by April had been carried through the border and was in existence in many states of the U.S. On the 25th April the Director General of the World Health Organisation (WHO), Margaret Chan, declared the swine flu a public health emergency of international concern. In the following few days cases were confirmed in Spain, Germany, Austria, United Kingdom, Israel, Canada and New Zealand, with suspected cases under surveillance in Australia, Chile, Colombia and France. Eight days after the announcement there was a total of 787 confirmed cases worldwide.

 

The unprecedented rate of air travel taking place in the modern era and the particularly highly contagious nature of the strain are to be held accountable for the global dissemination of the virus, which infected millions in it's path. In November 2009 the WHO declared that cases had been confirmed in 199 countries/overseas territories with the characteristics of the disease's spread being similar to those of the seasonal flu as were the symptoms. Majority of sufferers recovered without the need for medical treatment but there were still a considerable 284,500 fatalities. A vaccine was approved for use in the U.S. on September 15, 2009 and this along with other scientific advances were the main reasons the pandemic had such a low mortality rate of 0.03%.