Virus trap

Australian researchers have developed a unique technique to check the rapid growth of mouse population. The government-backed Cooperative Research Centre (crc) for Biological Control of Pest Animals has produced a genetically modified herpes virus that makes sexually prolific female mice infertile by blocking sperm from entering their eggs.

"We know it works in a shoebox-level experimental setting. Now we want to try it in a field setting," says Tony Peacock, director of crc. The centre has urged the Office of the Gene Technology Regulator -- Australia's watchdog on transgenics -- to grant permission for testing the virus in sample populations of mice.

Rigorous testing is required to prove the virus is species-specific -- it cannot be transferred to other animals or humans. The main beneficiary of the virus would be Australian farmers, who are one of the world's biggest exporters of grains.

Australia's mouse population explodes into billions every four years or so, usually at the end of a drought. Peacock says a bad mouse plague can cost Australia more than us $90 million in lost crops, while a moderate outbreak could cost us $30 million.