6Centers for Disease Control and Prevention(CDC).Update:novel influenza A(H1N1)virus infection-Mexico,March-May,2009.MMWR Morb Mortal Wkly Rep,2009,58(21):585-589.
7Shinde V,Bridges CB,Uyeki TM,et al.TripleRenssortant Swine Influenza A(H1N1)in Humans in the United States,2005-2009.J Wildl Dis.2009,45(2):519-521.