First Human Case of West Nile Virus Confirmed in London, ON

Public health officials have announced the first human case of West Nile virus in the London area for this year. This comes after the Middlesex-London Health Unit alerted the public about mosquitoes caught in several local traps testing positive for the virus. London is not alone; Ontario has seen a total of four confirmed human cases of West Nile, with 67 positive mosquito pools across the province.

Dr. Joanne Kearon, Associate Medical Officer of Health at the Middlesex-London Health Unit, noted that despite significant preventative measures, the unusually wet summer has led to a rise in the mosquito population. 'This human case highlights the urgent need for everyone to take precautions,' she said, urging the community to continue protecting themselves against mosquito bites.

The Middlesex-London Health Unit is actively monitoring mosquito populations through 23 trapping sites in London and Middlesex County. Their 17-week study, which runs until September, aims to control the outbreak. They are also treating public catch basins to manage the virus. Meanwhile, health officials emphasize that most people infected with West Nile virus show no symptoms. Those who do may experience fever, headache, and mild rashes. Rarely, severe symptoms can occur, affecting less than 1% of infected individuals.

To avoid contracting the West Nile virus, it is advised to wear light-coloured clothing that covers the body, especially during dawn and dusk when mosquitoes are most active. Using insect repellent with DEET and fixing any holes in window and door screens can also be effective measures. Regularly emptying standing water from your surroundings is essential to prevent mosquito breeding.

In a broader context, human surveillance of West Nile virus is part of a nationwide effort from mid-April to November. The Government of Canada collaborates with provincial health departments, First Nations authorities, and blood supply agencies to track the virus. Since 2002, when the first human case was reported, Ontario has continued to be a focal point for monitoring West Nile virus activity.

Each year, data is collected to understand the incidence and spread of the virus. In 2022, for instance, there were 47 human cases in Canada. This fluctuates significantly year-on-year, with the highest number being 2401 cases in 2007. These numbers highlight the critical need for ongoing vigilance and public awareness.

It's not just humans at risk—birds and horses are also monitored as part of the surveillance effort, with certain species acting as early indicators. Dead birds and infected horses often signal potential outbreaks in specific regions. This data helps public health authorities make informed decisions on where to intensify mosquito control measures to prevent the spread of the virus.

If you suspect that you or a relative may have contracted the West Nile virus, it's crucial to consult a healthcare provider for diagnosis and potential treatment. There is no specific treatment for the virus, so healthcare professionals generally recommend rest, hydration, and over-the-counter pain medications to relieve symptoms.

Although severe cases requiring hospitalization are rare, they do occur, predominantly affecting older adults and those with pre-existing medical conditions. However, most people recover without any lasting effects and believe they gain lifelong immunity from future infections.