The United States Army Medical Research Institute of Infectious Diseases (USAMRIID), located at Fort Detrick, Maryland, is the U.S. Army's leading facility for defensive research against biological warfare. Established from precursor units in the 1950s, it is uniquely equipped as the only Department of Defense laboratory capable of studying highly hazardous viruses at Biosafety Level 4, utilizing state-of-the-art biocontainment techniques pioneered in the 1960s.

With approximately 800 military and civilian personnel, USAMRIID's mission is to protect military personnel from biological threats and assist in public health outbreak investigations. Notably, it was the first bio-facility to research the Ames strain of anthrax, which was later identified as the bacterium used in the 2001 anthrax attacks. All of USAMRIID's research strictly adheres to President Richard Nixon's 1969 executive orders and the 1972 UN Biological Weapons Convention, focusing solely on defensive measures.