[Sydney, April 30. Image via Getty]

SYDNEY, AUSTRALIA - APRIL 30: A women wearing a face mask kisses a young girl upon her arrival at Sydney International Airport on April 30, 2009 in Sydney, Australia. The World Health Organisation has issued a Swine Influenza Virus (SIV) pandemic warning following the outbreak with positive reports of the virus spreading to the United States of America, United Kingdom and Europe. International travellers arriving in Australia with flu like symptoms are detained in quarantine until they are cleared of the infection. (Photo by Matt King/Getty Images)