State and county conservation workers across Iowa are now on the look-out for dead crows. Dr. Russell Currier of the Iowa Department of Public Health says it’s part of the effort to track the dangerous West Nile virus, a mosquito-borne disease.The West Nile virus killed seven people on the East Coast last year and there’s been one confirmed case so far this year. Currier says the crow isn’t the only indicator under health department surveillance, they’re also checking mosquitoes and keeping an eye on horses.Currier says once bitten by a virus-carrying mosquito, a crow will die within a week. He says they can test the dead crows to see if the disease is present.Currier says the West Nile virus has been detected as far west as Syracuse, New York, and as far north as Boston.