Virus

Events

1957
1959
1959
1964
May 1970
1971
1972
1974
1975
1976
Approx. 1979
1981
1986
1986
1987
1988
1989
1989
1989
1991
1991
1992
1992
1995
1998
1999
1999
2001
2001
2002
2003
2004
2005
2006
2007
2008
2011