Southwestern Public Health has confirmed the first human case of West Nile virus in the region this season.
The confirmation follows the detection of West Nile virus in mosquito pools collected in Woodstock and Tavistock through the health unit's routine mosquito surveillance program.
West Nile virus activity typically increases during the summer, with most locally acquired human infections occurring in August and September. Earlier this season, West Nile virus was detected in mosquito pools collected July 23, confirming that the virus was active in the region.
This is the first human case reported to Southwestern Public Health since 2018.
Most people infected with West Nile virus do not develop symptoms. About 80 per cent of infections are asymptomatic. Others may develop West Nile fever, which can include fever, headache, muscle aches, fatigue, rash, swollen lymph nodes, nausea, vomiting, diarrhea, eye pain or sensitivity to light.
Less than one per cent of infected people develop severe neurological illness.
“West Nile virus is present in our region, and this first human case is an important reminder to take precautions against mosquito bites,” said Dr. Ninh Tran, Medical Officer of Health at Southwestern Public Health.
Residents are being encouraged to take simple steps to reduce their risk.
That includes using insect repellent containing DEET or Icaridin according to label directions, wearing light-coloured clothing with long sleeves and long pants when outdoors, particularly around dawn and dusk, and making sure window and door screens are in good repair.
Residents should also eliminate places where mosquitoes can breed by emptying standing water from items such as buckets, flowerpots, toys, wheelbarrows and bird baths at least once a week.
SWPH also recommends keeping eavestroughs and drainage areas clean, properly maintaining swimming pools and decorative ponds, and covering or properly maintaining rain barrels.
Across Ontario, 167 human cases of West Nile virus were reported in 2025, compared with 77 cases in 2024.
SWPH continues to monitor West Nile virus activity through its mosquito surveillance program and encourages residents to take precautions throughout mosquito season.
