Brucella and all other remaining biological weapons in the U.S. arsenal were destroyed in 1971–72 when the American offensive biological warfare  program was discontinued by order of President Richard Nixon.The experimental American bacteriological warfare program focused on three agents of the Brucella group:
Porcine brucellosis (agent US)
Bovine brucellosis (agent AA)
Caprine brucellosis (agent AM)Agent US was in advanced development by the end of World War II. When the United States Air Force (USAF) wanted a biological warfare capability, the Chemical Corps offered Agent US in the M114 bomblet, based on the four-pound bursting bomblet developed for spreading anthrax during World War II. Though the capability was developed, operational testing indicated the weapon was less than desirable, and the USAF designed it as an interim capability until it could eventually be replaced by a more effective biological weapon.The main drawback of using the M114 with Agent US was that it acted mainly as an incapacitating agent, whereas the USAF administration wanted weapons that were deadly. The stability of M114 in storage was too low to allow for storing it at forward air bases, and the logistical requirements to neutralize a target were far higher than was originally planned. Ultimately, this would have required too much logistical support to be practical in the field.Agents US and AA had a median infective dose of 500 organisms/person, and for Agent AM it was 300 organisms/person. The incubation time was believed to be about 2 weeks, with a duration of infection of several months.
The last outbreak of brucellosis in Great Britain was in cattle in Cornwall in 2004. Northern Ireland was declared officially brucellosis-free in 2015. New Zealand
Brucellosis in New Zealand is limited to sheep (B. ovis). The country is free of all other species of Brucella. United States
Dairy herds in the U.S. are tested at least once a year to be certified brucellosis-free with the Brucella milk ring test. Cows confirmed to be infected are often killed. In the United States, veterinarians are required to vaccinate all young stock, to further reduce the chance of zoonotic transmission. This vaccination is usually referred to as a "calfhood" vaccination. Most cattle receive a tattoo in one of their ears, serving as proof of their vaccination status. This tattoo also includes the last digit of the year they were born.The first state–federal cooperative efforts towards eradication of brucellosis caused by B. abortus in the U.S. began in 1934.Brucellosis was originally imported to North America with non-native domestic cattle (Bos taurus), which transmitted the disease to wild bison (Bison bison) and elk (Cervus canadensis). No records exist of brucellosis in ungulates native to America until the early 19th century. History
Brucellosis first came to the attention of British medical officers in the 1850s in Malta during the Crimean War, and was referred to as Malta Fever. Jeffery Allen Marston (1831–1911) described his own case of the disease in 1861. The causal relationship between organism and disease was first established in 1887 by David Bruce.