Brucellosis neurobrucellosis. Brucellosis in humans is usually associated with consumption of unpasteurized milk and soft cheeses made from the milk of infected animals—primarily goats, infected with "Brucella melitensis" and with occupational exposure of laboratory workers, veterinarians, and slaughterhouse workers. Some vaccines used in livestock, most notably "B. abortus" strain 19, also cause disease in humans if accidentally injected. Brucellosis induces inconstant fevers, miscarriage, sweating, weakness, anaemia, headaches, depression, and muscular and bodily pain. The other strains, "B. suis" and "B. canis", cause infection in pigs and dogs, respectively. Definite diagnosis of brucellosis requires the isolation of the organism from the blood,
Swine brucellosis nickel transport, "nikA", is activated by metal ion deficiency and is expressed once in the phagosome. Nickel is essential for many enzymatic reactions, including ureolysis to produce ammonia which in turn may neutralize acidic pH. Since "B. suis" is unable to grow in a strongly acidic medium, it could be protected from acidification by the ammonia. Summary: The most frequent clinical sign following "B. suis" infection is abortion in pregnant females, reduced milk production, and infertility. Cattle can also be transiently infected when they share pasture or facilities with infected pigs, and "B. suis" can be transmitted by cow’s milk.