Gastrointestinal & Zoonoses

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Gastrointestinal & Zoonoses

West Nile Virus

Epidemiology

West Nile Virus infection is acquired from the bite of a mosquito, which itself becomes infected by feeding on an infected bird. Transmission through blood transfusion, transplant, breast milk and transplacentally has been reported. Currently, infection is not thought to occur in the UK, although infection could be acquired overseas.

Main clinical features

Infection is usually asymptomatic or mild (a flu-like illness with fever ). However, severe meningitis or encephalitis accompanied by fever can occur, more commonly in the elderly. Symptoms include: fever, rash, weakness, ataxia, altered mental status, and involvement of heart, liver and pancreas have also been reported. Case fatality rates of 10-15% have been reported among symptomatic patients.

Incubation period

3 - 14 days.

Surveillance

Voluntary laboratory reports.

Annual Surveillance Tables

In 2014 two imported cases were laboratory confirmed in Scotland. There have been no other confirmed cases to date.