West Nile virus

Key facts

1. West Nile virus can cause a fatal neurological disease in humans.
2. However, approximately 80% of people who are infected will not show any symptoms.
3. West Nile virus is mainly transmitted to people through the bites of infected mosquitoes.
4. The virus can cause severe disease and death in horses.
5. Vaccines are available for use in horses but not yet available for people.
6. Birds are the natural hosts of West Nile virus.
7. Cases of WNV occur during mosquito season, which starts in the summer and continues through autumn.