Increased number of mosquitoes test positive for West Nile Virus

HAMILTON , ON - August 21, 2017 - Residents are reminded to take precautions against West Nile Virus (WNV) infection after Hamilton Public Health Services received an increased number of mosquitoes within the city testing positive for West Nile virus. The City of Hamilton continually assesses the risk for human illness and has a comprehensive surveillance and prevention program. The current risk for Hamilton has moved from Moderate to High based on these positive results. 

Each week, an average of nineteen traps are set across the city in all wards from June to late fall. Fifteen batches of mosquitoes (mosquito ‘pools’) that were collected on August 15 from ten traps tested positive for West Nile virus.

As part of its prevention efforts, the City treats city street catch basins. The third round of treatment began August 8th and is nearing completion. A fourth round is being considered for early September dependent on ongoing surveillance for human cases, positive adult mosquitoes, local weather conditions, and other factors over the next few weeks.  Treatment of surface waters on public land is also ongoing including ditches and other areas where water may accumulate.

Areas with confirmed positive mosquito pools to date:

Area - Positive mosquito pools

Ancaster - 1

Dundas - 0

Flamborough - 0

Glanbrook - 1

Central Mountain - 2 

East mountain - 2

West mountain - 0

Lower Central Hamilton - 3

Lower East Hamilton - 5

Lower West Hamilton - 0

Lower Stoney Creek - 2

Upper Stoney Creek - 3

Total19
(15 in the week of August 15 and 4 prior this season)

Quick Facts

• Public Health Services reminds residents to avoid being bitten by mosquitoes.
• While most people infected with West Nile virus will have no symptoms (80%), others including the older adult or those with weakened immune systems may experience West Nile fever (20%) or they may develop more severe illness including inflammation of the brain or the lining of the brain (1%). For any infection, if symptoms do occur, they appear two to 14 days after being bitten by an infected mosquito.
• The most effective defense is to use a mosquito repellent containing DEET. When using mosquito repellent, carefully follow manufacturer's instructions
• Other ways to prevent being bitten include avoiding areas where mosquitoes are known to be present or  covering up with light coloured long sleeves and long pants when in  mosquito areas such as wooded areas, on the golf course, or in the garden, especially at dawn and dusk when mosquitoes are most active.
• Remember to continue to remove standing water at least weekly from your property.

For more information on West Nile virus please call the West Nile Virus line at 905-546-2489 during business hours, or visit www.hamilton.ca/westnile.