Brucella, named after David Bruce, belongs to the genus of Gram-negative bacteria. They are small (0.5 to 0.7 by 0.6 to 1.5 µm), nonencapsulated, nonmotile, facultatively intracellular coccobacilli. Figure 1 shows the schematic of Brucella Abortus:
Fig. 1 Model of Brucella Abortus
Brucellosis is a zoonotic disease of domestic and wild ungulates. Brucella spp. is facultative intracellular bacteria causing chronic disease that usually persists for life. Mortality in adults is rare, but mortality of offspring may be high in a recently-infected herd. Infection of the female reproductive tract often results in abortion. Eradication of B. abortus from cattle is nearly complete in the U.S., but the disease still occurs in some wild bison and elk herds in the western U.S.
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 the bacteria in tissues of the mononuclear phagocyte system, including the spleen, liver, lymph nodes, and bone marrow. Brucella can also target the male reproductive tract.
Brucellosis vaccines are comprised of living, mutant Brucella sp. organisms that infect the host, but are less pathogenic than the parent strain while providing prolonged immunity. Brucella abortus strain RB51 is a laboratory-derived rough mutant of virulent Brucella Abortus strain 2308 used as a vaccine because it induces antibodies that do not react on standard brucellosis serologic tests. Strain RB51 vaccine was evaluated in pregnant captive elk to determine if it induced abortion and if it protected against abortion following subsequent challenge. Scientists will find high quality Brucella Abortus Virus Antigens from Creative Diagnostics.