Gamston in Retford is among the places to undergo mosquito surveillance this summer as part of a national project to understand mosquito activity across Britain.

The UK Health Security Agency is working with Bassetlaw District Council and Nottinghamshire County Council to increase surveillance on land along the River Idle near Retford, Nottinghamshire, where nuisance biting from Aedes vexan mosquitoes has taken place in previous years.

Work has already been undertaken in Gamston to improve the natural environment by reshaping the wetland and reducing the flood risk to minimise suitable habitats for the mosquitoes, which has greatly improved the issue.    

Now, a research programme by the Animal and Plant Health Agency (APHA) and UK Health Security Agency (UKHSA) has identified fragments of West Nile Virus in historic mosquito samples collected from Gamston in 2023.

UKHSA has assessed the risk to the public as very low and will continue to visit the Gamston site fortnightly over the summer to collect further mosquito samples.

To date, there have been no human cases of locally acquired West Nile Virus in the UK. The main risk of West Nile Virus for UK residents continues to be travel to overseas areas, including parts of Europe, which have already been affected by the disease.

Vivienne Robbins, Director of Public Health and Communities for Nottinghamshire County Council, said:

“While the risk to the local population has been assessed as very low, we’re pleased to see further surveillance being carried out by UKHSA and APHA in Gamston.

“Work has been ongoing since 2018 with partners in this area to reduce the risk of nuisance mosquito biting. This has included actions to minimise suitable habitats for the mosquitoes, which will greatly improve the issue.

“This type of mosquito is native to the UK. Mosquitoes in the UK are also commonly found in wet woodland areas, ponds, ditches, marshes, and even garden water butts. To avoid being bitten by a mosquito, wear long-sleeved clothing and trousers to cover your arms and legs, use insect repellent on your arms and legs, or use blinds or screens to help keep mosquitoes out of homes.”

Craig Taylor, Director of Regeneration and Neighbourhoods at Bassetlaw District Council, said: 

“In Gamston, work has been carried out in recent years with the landowners to reshape the wetland and reduce the flood risk to minimise suitable habitats for Aedes vexan mosquitoes, which we believe will improve the issue.”

Dr Vanessa MacGregor, Consultant in Communicable Disease Control for UKHSA East Midlands, said:

“While this is the first detection of West Nile Virus in mosquitoes in the UK so far, it is not unexpected as the virus is already widespread in Europe.

“The risk to the general public is very low and there is nothing to suggest this disease is circulating in Gamston or anywhere else in the UK.

“We know that in the wake of climate change, mosquito-borne diseases are expanding to new areas. It is therefore important that we continue to carry out surveillance to provide early warning and continue to assess the public health risk.”  

ENDS

Notes to editors:

The UKHSA has issued a press release on the study First detection of West Nile virus in UK mosquitoes (GOV.UK)

West Nile Virus

West Nile Virus is a vector borne disease belonging to the Flaviviridae family, which also includes the viruses that cause dengue and yellow fever. It is usually found in birds, and typically circulates through bird-biting mosquitoes.

Occasionally, mosquitoes may bite both birds and humans or birds and horses, and in rare cases can transmit the virus to humans or horses. Neither humans nor horses represent a source of infection for mosquitoes or other animals.

Most people infected with West Nile Virus are asymptomatic or present with mild influenza-like symptoms such as fever, headache or myalgia, swollen lymph nodes and a rash. While most mild infections resolve within a few days, a small number of cases (under 1%) can cause more severe illness. 

West Nile Virus is endemic in various regions across the globe, including Europe, Africa, the Middle East, West and Central Asia, and North America, as well as South America, USA and Australia. The geographic range of West Nile Virus has expanded in recent years to more northerly and western regions of mainland Europe.

Research programme

The fragments were detected through the Vector-Borne RADAR (Real-time Arbovirus Detection And Response) programme* by APHA, using polymerase chain reaction (PCR) testing, in two samples of Aedes vexans mosquitoes collected by UKHSA from wetlands on the River Idle near Gamston (Retford), Nottinghamshire, during July 2023. The mosquitoes were pooled into groups of ten for testing, and fragments of West Nile Virus genetic material were identified in two of the pools. The other 198 were negative. This is the first evidence of West Nile Virus detected in a mosquito in the UK. A further 198 pools from the same site tested negative for the virus.

The Vector-Borne RADAR (Real-time Arbovirus Detection And Response) programme, funded by the UK Research and Innovation and the Department for Environment, Food and Rural Affairs, was created to help understand the emergence and transmission of zoonotic mosquito-borne viruses in the United Kingdom, and is also supported by the Institute of Zoology and British Trust for Ornithology. Part of its research has involved testing mosquito samples, both newly collected and archived from use in previous research, for the presence of West Nile Virus genetic material. A total of 32,000 mosquitoes have been tested through the scheme, with the latest samples tested submitted in 2024. Other types of mosquitoes tested include Culex modestus and Culex pipiens as the principal bridge and enzootic vectors.

A further 30,000 mosquitoes and 300 birds have been tested from areas of England most suitable for West Nile Virus, and all samples from 2023 and 2024 have tested negative.