171030-N-FP878-021 ROTA, Spain (Oct. 30, 2017) Hospitalman Jessica Ferguson, left, immunizes Logistics Specialist 1st Class Willson Villavilencio aboard the Arleigh Burke-class guided-missile destroyer USS Donald Cook (DDG 75). Donald Cook is forward-deployed to Rota, Spain, on its sixth patrol in the U.S. 6th Fleet area of operations in support of regional allies and partners and U.S. national security interests in Europe. (U.S. Navy photo by Mass Communication Specialist 1st Class Theron J. Godbold/Released)