GENEVA - All countries except the United States have now destroyed samples of a deadly flu virus that were inadvertently sent out by a US laboratory, the World Health Organisation (WHO) said Monday.
"Everybody has destroyed (the samples) except the United States," said WHO spokeswoman Maria Cheng.
US authorities were expected to complete destruction of the samples within the "next couple of days", Cheng said.
Laboratories in 18 countries had received the samples containing H2N2 "Asian" flu from the College of American Pathologists, sparking a global alert this month and a scramble to find the samples in more than 3,700 laboratories.
Ninety percent of the laboratories that received the samples since October 2004 were in North America.
The H2N2 strain is similar to the 1957 flu virus that killed up to four million people across the world in the late 1950s, and should not have been sent out in routine test kits for pathogens, according to the WHO.
Cheng said two samples that had been reported as missing on their way to Lebanon and Mexico had been destroyed.
The Lebanese sample was traced to a laboratory in the country, although the WHO could not say if it was the original destination.
The Mexican one was returned to the sender because of problems with import documents, while Cheng revealed that the third sample that had been unaccounted for was sent back from Chile for the same reason.
While the WHO praised the international response to the alert first sent out on April 8, the agency said it would be on guard for about 20 days.
"We'll probably want an incubation period before we declare this over," Cheng said.
Health experts have played down the risks of contamination, because the samples were freeze dried and swiftly deteriorated on exposure to room temperatures, water or sunlight.
The UN's health agency has demanded full investigation into the incident in the United States.
04/18/2005 16:25 GMT