Gwen Outen with the VOA Special English Health Report.

Health officials are investigating how several thousand laboratories worldwide received a deadly influenza virus by mistake. The laboratories normally receive small amounts of viruses to test their equipment. But the virus they received this time killed between one million and four million people in nineteen fifty-seven and fifty-eight.

The virus was sent in testing supplies to four thousand seven hundred laboratories in nineteen countries.

The World Health Organization reported that as of Monday most of the shipments had been destroyed. Eighteen countries had confirmed the destruction of the virus, with the United States expected to join them shortly. Laboratories in the United States had received most of the supplies.

The virus is named h-two-n-two. This so-called Asian flu disappeared in nineteen sixty-eight when new viruses began to spread. Health officials say anyone born since then would have little or no protection against the h-two-n-two virus.

W.H.O. officials say there is a risk that the virus could spread again worldwide if it escaped from a laboratory. But they said the danger of anyone getting sick was low if laboratory workers handled the virus carefully. There were no immediate reports of any cases of infection.

An American company shipped the virus starting last October. The last shipments were in February. The samples were sent as part of a testing process that measures how well laboratories can correctly identify viruses. The Meridian Biosciences company in Ohio shipped the tests for the College of American Pathologists.

Officials of the College of American Pathologists say they did not know that the h-two-n-two virus had been sent out. They say they will be more careful in the future to state exactly which viruses to send to laboratories.

Health officials in Canada informed the W.H.O. on March twenty-sixth that a local laboratory had discovered the deadly flu virus. The United Nations health agency then directed all the laboratories involved to destroy the samples as quickly as possible.

Federal officials in the United States are investigating the incident. And the World Health Organization will propose new safety rules for the handling of this kind of virus in laboratories.

This VOA Special English Health Report was written by Cynthia Kirk. I'm Gwen Outen.