The first human case of West Nile virus has been confirmed in Toronto.Toronto Public Health officials did not provide any further details, except to say that the laboratory-confirmed case is in an adult.The finding comes less than two weeks after the public health agency confirmed the presence of the virus in the city on July 18.Last year, the first human case of the virus was not confirmed until August 16.West Nile virus is a mosquito-borne illness that can be transmitted to humans through the bite of an infected mosquito. While most people experience mild or no symptoms, the virus can cause serious illness in some cases, particularly in older adults or those with weakened immune systems.Symptoms typically develop between two and 14 days after a bite from an infected mosquito and may include fever, headache, nausea, vomiting, body aches, skin rash and swollen lymph nodes.