Brucella abortus: A species of the genus BRUCELLA whose natural hosts are cattle and other bovidae. Abortion and placentitis are frequently produced in the pregnant animal. Other mammals, including humans, may be infected.Brucella: A genus of gram-negative, aerobic bacteria that causes BRUCELLOSIS. Its cells are nonmotile coccobacilli and are animal parasites and pathogens. The bacterium is transmissible to humans through contact with infected dairy products or tissue.Brucellosis: Infection caused by bacteria of the genus BRUCELLA mainly involving the MONONUCLEAR PHAGOCYTE SYSTEM. This condition is characterized by fever, weakness, malaise, and weight loss.Brucellosis, Bovine: A disease of cattle caused by bacteria of the genus BRUCELLA leading to abortion in late pregnancy. BRUCELLA ABORTUS is the primary infective agent.Brucella Vaccine: A bacterial vaccine for the prevention of brucellosis in man and animal. Brucella abortus vaccine is used for the immunization of cattle, sheep, and goats.Brucella melitensis: A species of the genus BRUCELLA whose natural hosts are sheep and goats. Other mammals, including humans, may be infected. In general, these organisms tend to be more virulent for laboratory animals than BRUCELLA ABORTUS and may cause fatal infections.Brucella ovis: A species of the genus BRUCELLA which are pathogenic to SHEEP.Brucella canis: A species of gram-negative bacteria infecting DOGS, the natural hosts, and causing canine BRUCELLOSIS. It can also cause a mild infection in humans.Abortion, Veterinary: Premature expulsion of the FETUS in animals.Antibodies, Bacterial: Immunoglobulins produced in a response to BACTERIAL ANTIGENS.Agglutination Tests: Tests that are dependent on the clumping of cells, microorganisms, or particles when mixed with specific antiserum. (From Stedman, 26th ed)Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Erythritol: A four-carbon sugar that is found in algae, fungi, and lichens. It is twice as sweet as sucrose and can be used as a coronary vasodilator.Chlamydophila: A genus of the family CHLAMYDIACEAE comprising gram-negative non CHLAMYDIA TRACHOMATIS-like species infecting vertebrates. Chlamydophila do not produce detectable quantities of glycogen. The type species is CHLAMYDOPHILA PSITTACI.Bison: A genus of the family Bovidae having two species: B. bison and B. bonasus. This concept is differentiated from BUFFALOES, which refers to Bubalus arnee and Syncerus caffer.Antigens, Bacterial: Substances elaborated by bacteria that have antigenic activity.Brucella suis: A species of gram-negative bacteria, primarily infecting SWINE, but it can also infect humans, DOGS, and HARES.Complement Fixation Tests: Serologic tests based on inactivation of complement by the antigen-antibody complex (stage 1). Binding of free complement can be visualized by addition of a second antigen-antibody system such as red cells and appropriate red cell antibody (hemolysin) requiring complement for its completion (stage 2). Failure of the red cells to lyse indicates that a specific antigen-antibody reaction has taken place in stage 1. If red cells lyse, free complement is present indicating no antigen-antibody reaction occurred in stage 1.Ochrobactrum anthropi: A species of gram-negative, obligately aerobic rods. Motility occurs by peritrichous flagella. (From Bergey's Manual of Determinative Bacteriology, 9th ed)Bacterial Vaccines: Suspensions of attenuated or killed bacteria administered for the prevention or treatment of infectious bacterial disease.Mice, Inbred BALB CBacterial Proteins: Proteins found in any species of bacterium.Virulence: The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.Spleen: An encapsulated lymphatic organ through which venous blood filters.Rose Bengal: A bright bluish pink compound that has been used as a dye, biological stain, and diagnostic aid.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Macrophages: The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)Buffaloes: Ruminants of the family Bovidae consisting of Bubalus arnee and Syncerus caffer. This concept is differentiated from BISON, which refers to Bison bison and Bison bonasus.Lipopolysaccharides: Lipid-containing polysaccharides which are endotoxins and important group-specific antigens. They are often derived from the cell wall of gram-negative bacteria and induce immunoglobulin secretion. The lipopolysaccharide molecule consists of three parts: LIPID A, core polysaccharide, and O-specific chains (O ANTIGENS). When derived from Escherichia coli, lipopolysaccharides serve as polyclonal B-cell mitogens commonly used in laboratory immunology. (From Dorland, 28th ed)Bacterial Outer Membrane Proteins: Proteins isolated from the outer membrane of Gram-negative bacteria.Vaccination: Administration of vaccines to stimulate the host's immune response. This includes any preparation intended for active immunological prophylaxis.Sheep Diseases: Diseases of domestic and mountain sheep of the genus Ovis.Hydroxybenzoates: Benzoate derivatives substituted by one or more hydroxy groups in any position on the benzene ring.Goats: Any of numerous agile, hollow-horned RUMINANTS of the genus Capra, in the family Bovidae, closely related to the SHEEP.