A new breed of ‘super rat’ with poison-resistant DNA is infesting towns and cities across Britain, scientists warned today.
Tests found the mutant gene protects the rodents from all known toxins – making them fitter, faster and ‘almost impossible’ to kill.
It is believed the resistance was caused by mother rats feeding the poison to their young and inadvertently increasing their immunity.
But now experts have identified an entirely new strand of DNA that wards off infection and attacks from rodenticides and pesticides.
Researchers at the University of Huddersfield said the gene is hereditary and passed from one generation to the next.
Rats are prolific breeders and the resistant gene adapts and grows in strength as it is passed it, making the pests more powerful and less prone to disease.
Professor Robert Smith, who led the study, said the new gene was proof of natural selection and evolution.
Prof Smith, dean of applied science, said the DNA was first discovered in rats in the Home Counties.
But he warned that it is now spreading to other parts of the UK including Swindon, Wiltshire, where rat catchers have reported a 500 per cent increase.
Professor Smith said: ‘Natural selection means that when you have a rat population in your town, poison will kill the ones that aren’t resistant, the ones that survive may have the gene, they then have babies who can receive the gene themselves.
‘There are mutations and changes in their DNA that alter the ability of rats to deal with these poisons.
‘The new breed will spread rapidly following the introduction of fortnightly rubbish collections’
‘This is the same gene that was found in Hampshire and Berkshire. There are large parts of Hampshire which are infested where pest controllers and home owners use modern poison and just can’t control rats.
‘It appears to be moving west and has now been located in Swindon and Bristol.
‘That is a resilient gene, and although it is in Swindon it doesn’t mean that all Swindon rats have it. But it is a warning of things to come.’
Britain’s rat population now stands at approximately 80 million, a rise of 208 per cent since 2007.
Brown and common rats can breed at six weeks old and a typical pair can produce a family of 200 in a short time.
Experts say it is still too early to say how many of these are ‘super rats’ with the new resilient DNA.
But they warn that the new breed will spread rapidly following the introduction of fortnightly rubbish collections.
Campaigners claim bins are often left overflowing with rotten food, giving all rats a staple source of food throughout the year.
It is now feared that unless the ban on super-strength toxins is lifted, rat numbers will rocket over the summer.
Britain’s rat population now stands at approximately 80 million, a rise of 208 per cent since 2007
In the past year, local councils have been called out to deal with 700,000 infestations, compared with 650,000 the previous year, according to the National Pest Technicians Association.
In York, the number of call-outs doubled, while Exeter reported a 66 per cent increase, and Salford saw a 40 per cent rise.
Earlier this year, the village of Flamborough in East Yorkshire was nicknamed ‘Ratville’ after an infestation of thousands of vermin.
Professor Smith said people are now turning to illegal forms of extermination like air rifles, dogs and banned poisons to control the problem.
He said: ‘I have been contacted by exterminators who really know what they are doing that have to use guns and traps.
‘But that is not good enough if rat levels get to infestation proportions and you are trying to get the problem under control.’ He added that homeowners could help by clearing undergrowth and keeping food scraps to a minimum.
‘Just because people cannot see rats that doesn’t mean they are not there,’ he said.
‘Rats like undergrowth, they do not like to be seen so they usually run from undergrowth to undergrowth and may be seen somewhere in between.
‘If those bushes, and similar type growth, which gives rats cover, can be removed there will be less places to hide and may be caught by cats and other predators.’
Alec Minter, director of Berkshire Pest Control, said: ‘There were literally hundreds and hundreds of them and they were causing the local people a real problem.
‘They had tried the usual baiting methods but the rats breed very fast and once a gene is thrown up which is resistant to the anti-coagulant control products available, they become immune.’
His colleague Jim Dunn added: ‘I used to use Warfarin to deal with them but don?t anymore because they’ve become immune to it.
‘We really need more powerful chemicals but health and safety restrictions mean we aren?t allowed.’
http://www.dailymail.co.uk/sciencetech/article-1182551/Coming-town-near-new-breed-super-rat-poison-resistant-DNA.html
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