First human case of West Nile Virus reported this season

HAMILTON, ON – Hamilton Public Health has confirmed the first local human case of West Nile virus (WNV) this season, prompting the Medical Officer of Health to move the WNV risk from moderate to high. 

Residents are reminded to protect themselves against mosquito bites and to remove standing water from private property to prevent mosquito breeding. Approximately 80 per cent of people infected with West Nile virus will have no symptoms. Others, particularly older adults or people with weakened immune systems, may experience West Nile fever or may develop more severe illness, including inflammation of the brain or the lining of the brain. This can occur in about 1 per cent of people infected with West Nile virus. If symptoms do occur, they appear two to 14 days after being bitten by an infected mosquito.

Take precautions to avoid being bitten by mosquitoes:

• Use a mosquito repellent (bug spray) containing DEET or Icaridin. 
• Avoid areas where mosquitoes are known to be present or cover up by wearing light coloured clothing with long sleeves and long pants when in mosquito areas. These areas include wooded areas, on the golf course or in the garden, especially at dawn and dusk when mosquitoes are most active.
• Reduce mosquito breeding sites by removing standing water at least weekly from your property. Mosquitoes lay their eggs in very shallow standing water. If you remove the standing water, they cannot lay eggs.

Hamilton Public Health continually assesses the risk for human illness as part of a comprehensive West Nile Virus surveillance and prevention program. Hamilton Public Health has completed its third round of larvicide treatments on city street catch basins, in addition to treatment of surface waters on public land to reduce mosquito populations and the risk of West Nile virus. 

“It is important to take precautions to avoid illnesses spread by insects including West Nile Virus, Lyme disease and Eastern equine encephalitis,” said Dr. Bart Harvey, Associate Medical Officer of Health. “Employing simple preventive measures, such as using insect repellent containing DEET or Icaridin, covering up, and removing standing water on your property to prevent mosquito breeding, will reduce your risk while you enjoy the outdoors. The risk of these infections will drop once there is heavy frost that reduces the number of mosquitoes.”

For additional information on West Nile virus and Hamilton Public Health’s mosquito control program, visit www.hamilton.ca/westnile or call 905-546-2489.

Additional Resources:

• Web page: City of Hamilton | West Nile Virus
• Web page: City of Hamilton By-Law: Standing Water at Specified Times of the Year
• Web page: Ontario.ca | Controlling mosquitoes on rural and farm properties
• Web page: Centers for Disease Control and Prevention | Eastern Equine Encephalitis Virus