Several thousand laboratory mice worth $20 each were infected with a contagious virus and destroyed earlier this month because they threatened two University research projects.

The privately funded researchers were attempting to genetically link the impact of alcohol and drugs to behavior and physiological processes, but somehow the mice became infected with the murine hepatitis virus -- a form of the disease found in mice.

David Blizard, senior research scientist at the Center for Developmental and Health Genetics and the project's co-investigator, said the only way to save the study was to sacrifice most of the animals because the disease is highly contagious to mice.

"It's essentially a painless procedure," said Frederick Ferguson, professor of veterinary science and director of the laboratory animal resources program. Ferguson said the mice were killed by carbon dioxide inhalation and then were incinerated to prevent further contamination.

"Obviously there aren't too many choices of what you can do with a dead animal carcass," he added. The mice were located at Research Building D.

The infection and destruction of the mice has greatly hampered research efforts, Blizard said.

"It really will affect our study and cause a major delay," he said, adding it will take six months to a year to get the half-completed study back on schedule.

Because the mice are of a specially bred strain and do not breed well, it will be difficult to derive a new colony, Blizard said.

A few hundred infected mice were saved in hopes that the study can be continued through their offspring. The infected mice will give birth through Caesarean section and the offspring will be placed with foster mothers, he said.

The baby mice could be free of infection because the virus is not thought to be transmitted through the placenta, Blizard said.

Although the virus is contagious among mice, it cannot be transmitted to humans, Ferguson said.

"It's specific just to the mice and at this point we're not sure how they were infected," he said.