LONDON - OCTOBER 24: A parrot looks out of its cage in a pet store on October 24, 2005 in London, England. The bird flu strain H5N1 has been discovered in a parrot which died in British quarantine, resulting in a call for a ban on the import of live birds into the country. Since 2003 the H5N1 strain has caused 60 human deaths and large losses of livestock in south-east Asia. The World Health Organization (WHO) has warned that millions could die in a global pandemic if a mutant form of the virus begins to pass between humans. (Photo by Scott Barbour/Getty Images)