Scientists are recruiting the public to join the first national mosquito watch this summer in an effort to determine whether disease-bearing mosquitoes are entering Britain.
People bitten in their homes and gardens are being urged to contact local health officials so that the insect culprits can be identified.
Government watchdogs warn that the climate here is already sufficiently warm and wet to support the dreaded Asian tiger mosquito, Stegomyia albopicta, which has been linked to 23 diseases, including West Nile virus and dengue fever. They fear that the 5m tyres imported into this country for recycling each year may prove prolific breeding grounds for the distinctive black and white mosquito that has spread rapidly from the south-east Asian forests through international trade and travel.
Discarded tyres may also offer shelter for their eggs which can survive for many years until conditions are ripe for hatching.
The survey includes inviting the public to report all suspect mosquito bites and to keep specimens they kill for detailed analysis. Environmental health officials and pest control technicians will also investigate complaints of insects in people's homes and gardens, and tyre dumping. Amateur insect hunters are being recruited to identify breeding grounds and possible new species.
The government's Health Protection Agency team responsible for preparing for such new health threats, based on Porton Down, Wiltshire, and the Chartered Institute for Environmental Health have organised the initiative. They need to map the prevalence of species, since existing knowledge is largely based on research up to 40 years old.
There is no evidence of mosquito-born viruses transmitted to humans in Britain in recent years - it is many decades since malaria was reported in the Kent and Essex marches - but antibodies to the occasionally fatal West Nile virus have been found in UK birds.
Last year two Irish tourists coming home from the Algarve in Portugal were found to have been infected and GPs have been warned to look for the warning signs, including flu-like symptoms and, in the most serious 1% of cases, inflammation of the brain and spinal cord.
Jolyon Medlock, senior scientist at the agency's centre for emergency preparedness and response, said yesterday that the Asian tiger mosquito could bring a variety of diseases. "The UK imports more than 5m used tyre casings annually and this seems the most likely route by which it could be imported."
The mosquito had been found in Albania, the US and several other European countries. It was endemic in Italy.
Mr Medlock said: "We have 33 recorded mosquitoes in the British Isles, some are very rare, a lot probably don't exist any more. A lot of our research is quite historical and dates back to the 1960s."
Scientists believe targeted checks on imported tyres might be needed. Contingency plans to combat West Nile virus include telling people not to have ponds or water butts in their gardens and use mosquito nets in their homes.
Study of weather patterns suggests conditions are already sufficient for the Asian tiger to survive in large parts of lowland UK, particularly around London and southern coastal ports.
About 200 people each year visit or return to this country having caught dengue fever while abroad. It too can be fatal.
No evidence of the Asian tiger has yet been found in Britain but another type of mosquito linked to West Nile virus, of the Culex genus, is already found in this country.
A website explaining the programme is on www.cieh-npap.org.uk
