Brucella include arthritis or epididymo-orchitis, spondylitis, neurobrucellosis, liver abscess formation, and endocarditis, the latter potentially fatal. Human brucellosis is usually not transmitted from human to human; people become infected by contact with fluids from infected animals (sheep, cattle, or pigs) or derived food products, such as unpasteurized milk and cheese. Brucellosis is also considered an occupational disease because of a higher incidence in people working with animals (slaughterhouse cases). People may also be infected by inhalation of contaminated dust or aerosols, and as such, the CDC has labeled "Brucella" species as highly weaponizable. Human and animal brucellosis share the persistence of
Elk bacterial disease brucellosis occasionally affects elk in the Greater Yellowstone Ecosystem, the only place in the U.S. where the disease is still known to exist. In domesticated cattle, brucellosis causes infertility, abortions and reduced milk production. It is transmitted to humans as undulant fever, producing flu-like symptoms which may last for years. Though bison are more likely to transmit the disease to other animals, elk inadvertently transmitted brucellosis to horses in Wyoming and cattle in Idaho. Researchers are attempting to eradicate the disease through vaccinations and herd management measures, which are expected to be successful. Nevetheless, research has been ongoing