澳门金沙游戏网站注册:Pandemics past: Seven times flu has become a mass killer


National Museum of Health and Medicine/SPL By Debora MacKenzie Winter flu breaks out every year because small mutations in the flu virus let it dodge antibodies we made to protect us from the last flu we got. It isn’t totally different from that last flu, so we are partly immune, and the infection may be mild. But every now and then an influenza A virus breaks out carrying surface proteins that are very different. This “pandemic” flu spreads like wildfire regardless of the season – and often more, and younger, people die. Survivors do gain some immunity for next time, so the killer settles down and becomes regular seasonal flu, drifting along until the next pandemic flu surfaces. Strain: unknown Deaths: unknown The first record likely to have been of a flu pandemic: “gasping oppression” with cough, fever and difficulty breathing rapidly spread across Europe after reportedly arriving from Asia via Africa. Similar events were recorded throughout the 1700s and 1800s. Strain: H3N8 or H2N2 Deaths: ~1 million The first pandemic to be spread faster by railways and steamships was recorded in St Petersburg in December 1889. Within four months, it had gone global, peaking in the US only 70 days after peaking in St Petersburg. Antibodies in survivors suggest it was an H3N8 virus, and so perhaps related to the H3N2 flu dominating in this northern hemisphere winter. Strain: H1N1 Deaths:
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