SCIENTISTS are studying the potential for a new, more potent strain of the rabbitkilling calicivirus after the failure of the existing virus in large parts of Australia's temperate regions. The government's chief scientist, Brian Cooke, said after the calicivirus' stunning debut in Australia's arid regions, the calicivirus was performing well below expectations in cooler areas, mainly in Victoria and New South Wales.

The initial result sent a wrong message and scientists thought extra efforts were not needed. "We want to see why it is not working well here. We probably hoped it would work well over a much bigger area. Perhaps it has not gone as far as I would have hoped," Cooke said.

The flagging performance of the disease has prompted a drive to get landowners to resume traditional rabbit eradication programmes, such as baiting and fumigation. Government scien- tists also have begun working on a programme to determine if temperate regions need a supercharged strain or a new dose of the calicivirus to boost the performance.