A species of mosquito capable of carrying the dangerous West Nile Virus was discovered in Kent and Essex in the United Kingdom last week. This particular species of mosquitos, called Culex modestus, was first discovered in the UK in 1945, but there was no evidence that it established a large population and it disappeared shortly after. The rediscovery of Culex modestus last week drew considerable attention because of the potential risk of spread of West Nile Virus. Several agencies in the UK are collaborating to study how widespread the mosquitos are, and whether or not there is any potential human danger. Scientists from the Centre of Ecology and Hydrology (CEH), the Health Protection Agency, and Oxford University are using satellite imagery to identify mosquito habitats before looking for them on the ground. Initial speculation suggests that this new population of mosquitos arrived relatively recently and via international travel or shipping, a similar method to how other mosquitos have spread in the UK.
West Nile Virus was first identified in 1937 in Uganda and is spread when a mosquito bites an infected bird and then bites a human. Its symptoms vary, with some cases being asymptomatic and a few cases developing severe symptoms. Common symptoms of West Nile Virus include fever, skin rash, diarrhea, lack of appetite and other mild flu symptoms, and less than 1 in 100 cases develop potentially lethal inflammation in the brain and spinal cord.
Despite there being no positive cases of West Nile Virus identified in the UK recently, as of January 2012 there were 96 confirmed human cases of West Nile Virus in Europe, reported in Greece, Hungry, Italy and Romania. West Nile Virus has appeared sporadically in Southern Europe throughout the past years, but as of today the virus has not historically been contracted in the UK.