Testing to determine if West Nile Virus has spread to humans in Missouri is underway at the State Health Lab in Jefferson City. Twenty-two people have been tested at the State Health Lab. No one of those tested has the disease. State Epidemiologist Barbara Wolcoff says the lab is responding to heightened concerns about the disease. West Nile has been found in birds in St. Louis, southeast Missouri and mid-Missouri. Two horses brought to the University of Missouri-Columbia vet school apparently died of it. Wolcoff says prevention is the best remedy. Eliminate standing water. Remove discarded tires. Use mosquito repellent. Repair any screens in the house. No cases had been reported in Western Hemisphere until 1999. Even if bitten by an infected mosquito, chances of severe illness is rare.