From the Document: "Since the Spanish-American War, the Department of Defense (DOD) has conducted 'global health engagement' (GHE) to prevent certain infectious diseases from threatening U.S. national security or military operations. Early GHE in partner nations and U.S.-controlled territories included site visits by epidemiological survey teams and establishment of DOD research laboratories to conduct research and monitor emerging disease threats. As a result, DOD has played a major role in discovering and developing vaccines for numerous infectious diseases, such as yellow fever, influenza, and most recently, Ebola."
CRS In Focus, IF11386
Congressional Research Service: https://crsreports.congress.gov/