Travellers to USA and Canada urged to be vigilant about West Nile Virus

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The National Disease Surveillance Centre today (Monday) urged intending travellers to the USA and Canada to be vigilant about West Nile Virus infection - a normally mild illness, but one that can produce severe infection of the brain - which has recently appeared in North America and usually peaks in late summer.

NDSC specialist in public health medicine, Dr Paul McKeown said that while there have been no reported cases of the disease in Ireland or the UK, it is important for travellers to be aware of this small, potential risk and of the appropriate preventative measures.

"West Nile Virus is spread by the bite of an infected mosquito. Four out of five people who are bitten will have no symptoms at all, while about 20% will develop a mild flu-like illness, with fever, headache and aches and pains. Less than 1% develop more severe disease which produces headache, high fever, stiff neck, sore eyes, disorientation, muscle weakness, convulsions and coma. 

"The risk of developing severe symptoms increases with age. Over 50s are about ten times more likely than children and young people to develop severe symptoms; the risk for those over 80 is almost 50 times higher. People with weakened immune systems are likely to be more vulnerable to severe disease.

"About 7% of severe cases in the US have died as a result of complications of West Nile Virus. These were mostly in the 50 plus age category. Last year, the US had over 4,000 cases including 284 deaths, while Canada reported almost 400 cases for the same period.

"People should enjoy their holidays in the USA and Canada as normal. The best way to protect yourself against West Nile Virus, is to protect yourself against mosquito bites. Travellers should note that mosquitoes carrying West Nile Virus are most active at dawn and dusk. Where possible, people should avoid areas near water where mosquitoes are more likely to be present. Long sleeves, long trousers, socks and closed shoes should be worn and mosquito repellents used. When indoors, screens, nets and air conditioning can reduce the possibility of mosquito bites.

"There is no specific treatment or vaccine for the disease. Mild cases recover quickly with simple symptomatic ('cold and flu') treatment. More severe cases require hospitalisation and specialised supportive treatment."