Officials with the Maryland Department of Health said in a statement that the infected person lives in the Baltimore region.
This comes one week after Toronto Public Health confirmed the first human case of West Nile virus in the city in 2018.
West Nile virus is a potentially serious illness that is usually spread to animals and humans through the bite of an infected mosquito.
Dr. Tim Hilderman, a medical officer of health with Manitoba Health, said Thursday the child has been released from hospital and is at home doing well.
We have a health alert out of Scioto County where the West Nile Virus has been found in some mosquitoes in the Portsmouth area.
However, the season isn't over yet, and the number of "vector" mosquitoes is increasing as the summer moves on, he said.
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The positive test in Oakville came from mosquitoes trapped this week. There were no reported cases of West Nile in the county past year.
The infection can even affect the central nervous system and last for months or years.
Experts say most people who are infected have no symptoms or experience only mild, flu-like symptoms. Those most susceptible are people 50 years old and older and those whose immunity is suppressed because of a disease such as cancer or diabetes.
Most people infected with the virus do not show symptoms, although more severe symptoms may occur, including fever, headaches, body aches, fatigue, nausea, vomiting, and sometimes swollen lymph glands or a skin rash.
As always, eliminate standing water on your property to prevent the development of Culex tarsalis mosquito populations.