Avian (Bird) Flu
H5N1 – HPAI virus
1997
Nearly 60% of those infected died

Spanish flu
H1N1
1918 – 1920
Infected 500 million worldwide (about 27% of the world population)
Fatalities: {estimated} 17-50 million

Swine Flu
N1H1
2009
Infected about 700 million to 1.4 billion or 11–21% of the global population (of about 6.8 billion)
Fatalities: about 150,000 – 575,000

highly pathogenic avian influenza (HPAI) virus