FAQ: West Nile virus

What is West Nile virus?

West Nile virus is a mosquito-borne virus that can cause West Nile Non-Neurological syndrome or occasionally the more serious West Nile Neurological Syndrome.

WNV is transmitted to humans primarily through the bite of an infected mosquito.

WNV can affect anyone – one in five people who do become infected become ill.

Severe illness associated with the virus is rare, but risk increases with age. However, the good news is that you can take some simple steps to protect yourself and others.

Tips to protect yourself

The most effective means of reducing the risk of infection with West Nile virus is to avoid mosquito bites. Simple steps to protect yourself and your family include using a mosquito repellent containing DEET, and wearing long-sleeved shirts and pants when outdoors during periods of peak mosquito activity.

What effect does West Nile virus have on people?

While most people who become infected with West Nile virus will experience no symptoms, one in five will develop West Nile Non-Neurological syndrome. Symptoms can include fever, severe headache, body aches and possibly a rash. Very few individuals will experience the more severe symptoms of West Nile Neurological Syndrome.

The neurological syndrome can include high fever, worsening headache and neck stiffness, stupor and disorientation, coma and tremors, occasional convulsions, paralysis, muscle weakness and numbness or difficulty moving. Long-term neurological effects have occurred in about 50 per cent of cases of West Nile Neurological Syndrome. In very rare cases, a West Nile virus infection can be fatal.

Is there a treatment for West Nile Neurological Syndrome?

There is no specific treatment for West Nile Neurological Syndrome.

More severe cases may require intensive supportive therapy – hospitalization, intravenous (IV) fluids, airway management, respiratory support (ventilator) if needed, prevention of secondary infections (pneumonia, urinary tract, etc.) and good nursing care. Recovered individuals can require physical or occupational therapy.

Are animals also infected by West Nile virus?

Birds are the main hosts for West Nile virus. Birds of the Corvid family (crows, magpies, ravens, blue jays and grey jays) are particularly susceptible. Bird survillance in previous years has provided a good understanding of the location and cycle of the virus.

For more information on disease in birds visit the Alberta Sustainable Resource Development website.  

– All information courtesy Alberta Health Services.