West Nile virus detected in UK mosquitoes for the first time

The British Equestrian Veterinary Association (BEVA) has announced that West Nile virus has been detected in UK mosquitoes for the first time, although the associated risk to horses and humans is currently considered very low. This announcement follows the UK Health Security Agency's (UKHSA) statement, issued on May 21, confirming the identification of genetic material from the virus in mosquitoes collected in Britain. West Nile virus, primarily transmitted through mosquitoes, can impact birds, humans, and horses.

Reports indicate that no local transmission cases have been observed in equines or birds within the UK. So far, all confirmed cases of the virus in horses have been linked to travel outside the country. Most horses infected with West Nile virus do not display visible symptoms. When symptoms do occur, they may include muscle tremors, weakness, stiffness, ataxia, or even recumbency. The severity of the virus can range from mild to fatal. According to the British Horse Society (BHS), infected horses and humans cannot transfer the virus to others, and many horses can fully recover. However, some cases may experience long-term effects such as gait abnormalities.

The mortality rate among horses that show clinical signs of the virus is reported to be between 35% and 45%. Despite the detection of the virus, the UKHSA has emphasized that there is no evidence of ongoing circulation in birds or mosquitoes in the UK, maintaining that the public risk remains very low. The findings were made through a collaborative research initiative between the UKHSA and the Animal and Plant Health Agency.