Chipotle shares closed down by 4.3 percent on Tuesday after the Mexican grill chain temporarily closed a Virginia restaurant where customers had reportedly fallen ill. The company said the shutdown in the Washington, D.C., suburb of Sterling, Virginia, came after a "small number" of reported cases of symptoms consistent with norovirus, which it noted "does not come from our food supply." The company said the restaurant would undergo a "complete sanitization" before reopening. The scare came as the restaurant chain struggles to recover from damage it suffered during previous food safety incidents, including an E. coli outbreak and a norovirus case in 2015. Chipotle has since altered its cooking methods and provided more food-safety training for workers.