The chief master sergeant initially tested positive for MERS on Wednesday. Because he showed no symptoms of the illness, he received further testing which reconfirmed that he has MERS.
The sergeant had received treatment for his Achilles heel at the same hospital as the first MERS patient in Korea, who became sick after visiting four Middle Eastern countries.
There are no other diagnosed cases of MERS on base, according to a statement released by Osan Air Base on Thursday. But six civilians and 64 soldiers -- all Koreans -- remain under quarantine in their barracks to prevent further infection on the base.
The Osan Air Base, located south of the capital Seoul, was built by the United States during the Korean War.
