First human West Nile virus case reported in Ottawa

OTTAWA – Ottawa Public Health (OPH) reported they have their first case of West Nile Virus in Ottawa this season today (Sept. 25).

“OPH has received lab notification of the first human case of West Nile virus infection in Ottawa for the 2019 West Nile virus season,” OPH staff released in a statement today. “Final lab confirmation is pending.”

On warm days, mosquitoes potentially carrying West Nile virus can still bite and transmit the infection to humans. This will continue until Ottawa experiences the first few hard frosts of the fall season.

“Ottawa Public Health reminds all residents to continue to protect themselves from mosquito bites,” the OPH said. “Culex pipiens, the northern house mosquito – the mosquito most responsible for spreading West Nile virus infection – prefers to live and breed around human habitations. Mosquito trapping and testing in Ottawa has found relatively low West Nile virus activity this year, but the risk for human West Nile virus illness is still present.”

West Nile virus is an infection that, in a small number of cases, can cause serious illness. Most people will not develop any symptoms if infected with West Nile virus, but about 20 per cent may experience flu-like symptoms including fever, headache, muscle aches and, possibly, a rash. The risk for more serious illness, in which West Nile virus invades the central nervous system – occurring in less than one per cent of all infections – increases with age. Older adults and the elderly are at higher risk, as well as people with weakened immune systems.

In Ontario, as of Sept. 14, there have been four human cases this year. In 2018, Ottawa had seven human cases, and Ontario had 137.

OPH urges residents to protect themselves and their families from mosquito bites by:

  • Applying a Health Canada-approved mosquito repellent containing DEET or icaridin to exposed skin and clothing
  • Protecting yourself, especially between dusk and dawn, when mosquitoes are most active, and any time you are near shady, bushy, or wooded areas
  • Wearing light-coloured, tightly woven, loose-fitting clothing, such as long pants, a long-sleeved shirt, shoes and socks, to protect exposed skin
  • Making sure all windows and doors in your home have screens that are in good condition
  • Reducing standing-water sites around your home, such as bird baths, toys, flower-pot saucers, swimming-pool covers, old tires, wheelbarrows, buckets, and cans
  • Keeping all openings to rain barrels covered with screen mesh at all times

“OPH has a proactive plan to deal with West Nile virus that includes weekly surveillance and mosquito larvicidal treatment of natural and man-made standing-water sites on city property, like ditches and stormwater management ponds,” the OPH said. “As part of this plan, Ottawa Public Health regularly applies larvicide in City-owned roadside storm-sewer catch basins to reduce the mosquito population.”