Mosquito which carries deadly West Nile virus disease living in Kent marshes more than 70 years after vanishing from UK
Mosquito species may have arrived via international shipping
663 cases of the virus in the U.S in 2009
A species of mosquito capable of transmitting the deadly West Nile virus to humans has been discovered breeding in Britain for the first time since 1945.
West Nile virus mostly infects birds but can be transmitted from birds to humans by the bites of mosquitoes.
While symptoms usually include fever, skin rash or swollen lymph glands in can prove fatal if it enters the brain.
Blood sucker: The species has been found breeding in the marshes of north Kent and south Essex over the past two years
'It's not clear how long this species of mosquito (Culex modestus) has been in the UK,' said Nick Golding of Britain's Oxford University and the Center for Ecology and Hydrology (CEH), who conducted the research.
He added that although the mosquitoes have been found at sites in the marshes of north Kent and south Essex in 2010 and 2011.
'It's something to watch,' he said.
The disease first appeared in the U.S in 1999 after circulating in Israel and Tunisia. There were 663 cases of the virus in America in 2009.
Mr Golding suggested the new population had arrived fairly recently, possibly via international shipping.
Disease surveillance experts suspect the Culex modestus species may be behind recent sporadic epidemics outbreaks of West Nile virus in southern Europe.
The virus, which survives in nature in a cycle involving transmission between birds and mosquitoes, is commonly found in Africa, the Middle East, North America and West Asia and can cause neurological disease and death in people.
West Nile virus can cause encephalitis or meningitis if it enters the brain
Miles Nunn, a molecular parasitologist at CEH who reviewed the findings, said that in continental Europe Culex modestus mosquitoes are able to transmit West Nile virus because the virus can reproduce inside them, and then gets passed on when the mosquito feeds on both humans and birds.
'However, in the UK the mosquitoes biting habits and ability to transmit West Nile virus have yet to be investigated,' he said.
A team from Oxford University and the Health Protection Agency are now conducting more studies to see how widespread the mosquitoes are and whether there is any risk to human health.
The Stockholm-based European Center for Disease Prevention and Control (ECDC), which monitors disease in the European Union, said that as of January 13, 96 confirmed human cases of West Nile virus had been reported in the EU.
More than two-thirds of them were in Greece with others in Hungary, Italy and Romania.
A handful of Culex modestus were
collected on the southern coast of Britain and recorded more than 60
years ago, but didn't appear then to be an established population.