The company at the center of distress over the shipment of samples of pandemic flu virus to thousands of labs apparently wasn't even aware it had sent such a deadly virus.

The College of American Pathologists (search), which helps labs to proficiency testing, had asked Meridian Bioscience Inc. in suburban Cincinnati to send a test kit of germs to about 4,700 labs — mostly in the United States, but also in 17 other countries. Meridian makes such kits and provides them to labs for their proficiency testing.

Dr. Jared Schwartz (search), an officer with the pathologists college, said Meridian thought it had sent an ordinary flu strain. He said Meridian workers found a virus in their "germ library" from the year 2000, which they'd gotten from another company which had obtained it from yet another company.

According to Meridian's process and evaluation they thought it was "an innocuous, typical influenza A virus, the kind of virus they've used before in our programs," Schwartz said.

Meridian executives were traveling and not available to comment, spokeswoman Brenda Hughes said.

Dr. Julie Gerberding (search), head of the Centers for Disease Control and Prevention, said labs doing proficiency tests generally only identify whether a flu virus is in the sample and whether it is a type A or B — not further sub-typing.

"That's why we didn't learn about this earlier in the process," she said.

So the deadly strain was in many labs for months before one lab discovered that the sample was the deadly H2N2 Asian flu virus (search) from the 1957 pandemic.

That virus has been seen little since the '50s, but officials said the World Health Organization's call to destroy the samples was a precaution against an outbreak. People born after 1968, when the strain was last included in vaccines, would have no immunity against the strain.

"While a few H2N2 laboratory acquired infections have been documented in the past, the likelihood of laboratory-acquired influenza infection is considered low when proper biosafety precautions are followed," Meridian said in a statement. "The risk for the general population is also considered low."

The WHO also has said the risk of an outbreak is slight.

Meridian's small employee parking lot was full Wednesday at its two-story, tan stone building tucked among fast food restaurants, gas stations and other businesses along a commercial strip.

Wednesday morning the company reiterated its outlook for the fiscal year ending in September, saying it continues to expect profits of 66 cents to 70 cents per share on sales of $84 million to $88 million.