ST. PAUL, Minn. - The Centers for Disease Control reports there have been four human cases of the West Nile Virus in Minnesota this summer.

All four cases, the CDC says, were confirmed following blood donations. In each case the people had no symptoms at the time of donating blood through a blood collection agency, but whose blood tested positive when screened for the presence of West Nile virus.

August and September are traditionally the peak times for virus transmission of the mosquitoborne virus. MDH says there were 30 West Nile cases last year and 83 the year before. West Nile was found in Minnesota in 2002.

This year, West Nile has not yet been found in a Wisconsin resident.

For more information about West Nile, click here.