WNV Vector found in UK
A species of mosquito believed to be a vector of transmission for the West Nile Virus (WNV) to humans and animals in Europe has been detected in marshland in North Kent and South Essex. The mosquito, known only by the Latin name Culex modestus, has not been seen in the UK since a handful of sightings were recorded in 1945.
WNV has never been found in the UK, although there have recently been outbreaks in France, Portugal and the USA. The virus is much more prevalent in warmer climates and routinely infects both wildlife and humans in Africa, the Middle East and South-West Asia. The virus is primarily found in birds, and mosquitos that feed on the blood of infected birds spread it to humans or animals when they feed after becoming infected in turn. The disease is mild in most cases and often produces no symptoms, although it can become severe in certain cases.
'In the UK, the mosquito's biting habits and ability to transmit West Nile Virus have yet to be investigated, ' said Dr Miles Nunn of the Centre for Ecology & Hydrology (CEH). 'Culex modestus is difficult to distinguish from related mosquitoes that are less likely to transmit viruses to humans. Its discovery highlights the importance of expert long-term biological recording of UK wildlife by the scientific community.'
Precisely how these non-native mosquitos entered the UK is not known for certain, but the mosquito is unable to fly far under its own power and a preliminary hypothesis has been proposed arguing that the mosquitos came in by ship. The large number of international shipping terminals in the area where the species seems to be established supports this theory.
Although there is no indication that WNV is present in the UK, the CEH, Health Protection Agency and scientists at Oxford University are working together and are using satellite imagery to establish the size and prevalence of the mosquito colonies on a precautionary basis. As Culex modestus needs specific conditions to thrive, the effect wetland management has on such habitats is also being investigated.
Defra has published guidance for the vet sector ahead of a proposed UK-EU Sanitary and Phytosanitary agreement.
