Lt. Cmdr. Gregg Langham and Sgt. Leona Thomas inject cattle. U.S. Public Health Service Lt. Cmdr. Gregg Langham (center) and U.S. Army Sgt. Leona Thomas (right) inject cattle with anti-parasite and tetanus vaccinations at the Dos Potrillos Ranch in Villanueva, Nicaragua, on July 22, 2007. Langham and Thomas are attached to the hospital ship USNS Comfort (T-AH 20). The Military Sealift Command hospital ship is on a four-month humanitarian deployment to Latin America and the Caribbean to provide medical treatment to patients from a dozen countries. SHARE: Download: Full Size (0.04 MB) Credit: VIRIN: 852352-T-XST64-899.jpg Photo Gallery