Mutant rats immune to poison

specialists have warned the problem is spreading across the country and claim it has been caused by council cuts in pest control and members of the public using dosages that are too low.
Rats must be fed the correct lethal dose when poison is put down, otherwise they begin to build up resistance.
These rats are then merely fattened up and strengthened by the bait, with survivors going on to mate with other resistant rodents.
Traces of the toxins are then passed on through the mother’s milk and within a few generations mutant rats develop that are immune to the chemicals used for pest control.
Peter Crowden, director of Rutland Pest Control, blamed the recession for forcing people to cut down on both expert help and poison.
He told the Daily Telegraph that householders were being forced to lay poison themselves due to council cost cutting, but are putting down smaller doses to save money.
Dr Dougie Clarke, head of biological sciences at Huddersfield University, and colleagues found 75 percent of rats in Bristol, Gloucestershire and Wiltshire were able to survive poisoning.
He warned that within ten years all rats in Gloucestershire, Wiltshire and Bath could be immune to the poisons.
“Some pest control companies are still using the same rodenticides — Bromadiolone and Difenacoum —  in areas where there are resistant rats and things need to change,” he said. — Daily Mail.