West Nile Virus is a disease that was first isolated in 1937 in the West Nile region of Uganda and is transmitted to people by infected mosquitoes. The majority of infected individuals have mild or no symptoms. However, the elderly and those with certain chronic medical problems including problems with their immune systems can become ill. West Nile Virus can cause an inflammation of the brain known as encephalitis.
Lyme disease is caused by the corkscrew shaped bacteria, Borrelia burgdorferi. In Ontario, this bacteria is spread by the bite of infected blacklegged ticks (commonly called deer ticks). Blacklegged ticks are the only type of tick in Ontario that can consistently transmit Lyme disease. The blacklegged tick can be found sporadically throughout Ontario.