Portions of Lake Tahoe will close after chipmunks tested positive for plague. The chipmunks have not come into contact with any humans but officials are taking every precaution to protect visitors. Plague is currently present in California and Colorado and can cause symptoms including nausea, weakness and swollen lymph nodes in humans when bitten or in close contact with infected animals, according to the California Department of Public Health. Last year, someone in California tested positive for the first time in five years. The U.S. Forest Service will begin vector treatments of affected areas and hope to open the park by the weekend, Tahoe Daily Tribune reports.