Randy and indestructible Spanish super-mice are set to invade our homes.
Rodents from across the continent have mated with vermin from the UK to create the mighty new breed – and experts say the critters have genes which are immune to the usual poisons, making them extremely hard to kill.
Scientists warned years ago that mice in Spain and Germany had developed resistance to the strongest anticoagulants, but added they had not yet made it to Britain.
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But the Campaign for Responsible Rodenticide Use said a breed of the Spanish mouse has now been found in Hertfordshire for the first time.
And they will soon be racing like Spanish-speaking critter Speedy Gonzales to new areas of the country.
CRRU chairman Dr Alan Buckle confirmed the latest study found a new four-component ‘spretus’ resistance strain – and said it would soon spread to London.
He said: “This was acquired by house mice in Spain through interbreeding with the Iberian mouse species, Mus spretus.
“The Hertfordshire spretus mice have almost certainly come in from the continent. More generally, London is now a clear hot-spot for mice with both single-gene and hybrid resistance.”
Findings by CRRU has found genes for resistance to anticoagulant rodenticides in as many as 95% of house mice.
Dr Buckle said these include “small but troubling numbers” with two or more such genes, labelled ‘hybrid resistance’.
He warned that the latest findings suggest there are now very few places in England where rodent populations could be killed by pesticides.
Dr Buckle added: “Continued use of anticoagulant rodenticides against resistant rats or mice has serious downsides: Incomplete control with consequent ongoing threats to human and animal health; faster geographical spread of surviving resistant individuals; and lengthy survival of resistant pests carrying persistent anticoagulant residues that could be taken as prey by predators.”
In 2011 scientists said German and Spanish mice had found a rapid method of overcoming the threat of anticoagulants by cross-breeding with Algerian mice that are, according to the researchers, an entirely different species.
The Current Biology report said this process could yield mice resistant to almost any form of pest control.
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