Advice for those travelling to Canada and the USA

The risk of acquiring West Nile virus (WNV) infection if you travel to the USA or Canada is low. There have only been two reported cases of people coming back to the UK with the disease. Most people who are infected do not get symptoms; less than 1% of persons infected with WNV will develop serious illness. However, it is important that travellers, particularly those aged 50 years and over who are more at risk of developing severe disease, going to areas where there is active transmission to humans are aware of the potential risk and take the appropriate anti-mosquito measures.

A total of 1021 human cases of WNV infection were reported in the USA during 2010. Up to date information can be obtained via the WNV pages on the CDC website.

In Canada, only 4 cases were reported in 2010. The most up to date information can be obtained from the Public Health Agency of Canada website.

Most of the mosquitoes that carry the WNV are especially likely to bite around dusk and dawn. If you are outdoors around these times of the day, do everything you can to reduce mosquito bites. Wear loose fitting lightweight clothing that covers up the skin as much as possible. Use an effective insect repellant on exposed skin and clothing in accordance with the manufacturer's instructions. Indoors, mosquito bites can be reduced by air conditioning, insect-proof screens on windows and doors and spraying the room with insecticide. Bed nets and cot nets can be used if necessary. There has been virus found in some day-biting mosquitoes too, so reducing bites at any time is a sensible precaution. Taking these simple measures will also help to protect you against other mosquito-borne diseases, which are occasionally encountered in North America.

For more travel information, see the National Travel Health Network and Centre website

• West Nile virus information
• Insect bite avoidance information

Last reviewed: 23 August 2011