Scientists at a Birmingham university have come up with a new way of controlling rats to prevent the spread of poison-resistant animals.
Conventional traps use poisoned bait, but they have led some animals to build up an immunity, researchers at Aston University said.
Rats are passing resistance to traditional rat poison
on to their offspring
Because there's no way to control how much poisoned
bait a rat eats it is possible for some animals to develop
a resistance over time.
Given the speed with which rats breed, that resistance
can quickly be passed on to a new generation.
But spraying rats with the exact dose of poison needed
to kill them sidesteps this whole problem.
For farmers in particular, where rats can cause huge
damage to crops, this new approach will be watched
with a great deal of interest.
Despite being a European project it's likely it will be
approved in America first.
But the scientists are pretty upbeat and have said if all
goes well it could be as quick as 18 months, although it
might take longer, depending on the commercial side
So-called super-rats have been found across Britain.
A new trap devised at Aston University delivers a poison in spray form directly on to a rat's skin to kill it.
As the rat enters the trap it breaks a laser beam. An onboard computer then calculates the exact dosage required, depending on the size of the rat.
The project has been backed by the European Union, although the toxin used in the trap will still require separate approval from the body before commercial use.
In contrast to the new device, researchers said it was impossible to control the amount of poison that a rat consumes in a traditional trap, meaning many survive, develop an immunity and have even started to pass that on to their offspring.
According to local authorities in the West Midlands, some 48,500 rat control treatments were carried out in 2013, making it one of the busiest areas in the country for call-outs.
Andrew Ingham, from Aston University, said pest controllers were often turning to higher and higher doses of traditional poisons to kill rats.
"You often don't notice there's a huge amount of poison hidden in a black box at the side of the road or at the side of your house," he said.