Читать книгу Vaccines For Dummies - Sharon Perkins - Страница 24

H1N1, another type A flu, has been a big worry for us in the past. An H1N1 subtype was the cause of the 1918 influenza pandemic (also called the Spanish flu), which led to the loss of more than 50 million lives worldwide and 650,000 in the United States. This subtype had genes of avian origin, though we haven’t yet figured out where it originated.

H1N1 has made news again and more recently caused concern when it began to spread in 2009. The virus crossed over from pigs, which is how it got its name: swine flu. However, H1N1 isn’t the only subtype of influenza to originate in pigs; the 2009 version, ultimately dubbed A(H1N1)pdm09, was, however, a new and unique variant not specifically seen before in animals or people, although it was related to prior H1N1 outbreaks.

Swine flu influenza viruses are spread, like other influenza viruses, through droplets in the air or by touching something that, for a graphic example, your pig has sneezed on, and then touching your mouth, nose, or eyes. While the first few cases were found in people who had direct or close contact with pigs, later cases were found to be from person-to-person contact. A vaccine was developed by the end of the year, and the pandemic ended by August 2010, according to the World Health Organization (WHO). In the United States, the CDC estimated there were about 60 million cases and 12,469 deaths from swine flu within the year after it was discovered, with worldwide deaths estimated at around 150,000 to 575,000.

Pigs can have other subtypes of influenza. Subtypes can also mix between birds and pigs before reaching us.