Brucella

Brucella is a bacteria that spreads from animals to humans most commonly through ingesting a contaminated food product or direct contact with an infected animal. Human to human contact is very rare. The incidence of confirmed infection in humans in the US hovers just over 100 cases total. The incidence in other parts of the world is higher.

Characteristics
Brucella is:
 * Gram-negative - does not retain a crystal violet stain used in the differentiation process
 * coccobacilli - has a shape intermediate between cocci (spherical bacteria) and bacilli (rod-shaped bacteria)
 * non-spore-forming
 * non-motile
 * aerobic - grows in the presence of oxygen
 * zoonotic - spreads to humans from animals

Classification
There are six species of Brucella. Three can cause serious disease in humans: Brucella abortus, Brucella melitensis and Brucella suis. One species, Brucella canis causes mild disease and the other two species have not affected humans.

Brucellosis
The disease caused by a brucella infection is called brucellosis. It causes an acute febrile illness associated with rigors, sweats, malaise, anorexia, headache, pain in muscles, joint, and/or back, and fatigue. If untreated, it can potentially cause a debilitating chronic infection in humans with reoccurring fevers, arthritis, swelling of the testicle and scrotum area, swelling of the heart (endocarditis), neurologic symptoms (in up to 5% of all cases), chronic fatigue, depression, swelling of the liver and/or spleen.

Risk for exposure
The people most at risk for acquiring a Brucella infection are people who :
 * consume undercooked meat or unpasteurized milk products from an infected animal
 * slaughterhouse workers
 * meat-packing plant employees
 * veterinarians
 * hunters dressing an infected animal
 * laboratory workers who handle the bacteria
 * an infant breastfeeding from an infected mother

Treatment
Treatment is a combination of broad spectrum antibiotics.

Lean more

 * Brucellosis: an Overview
 * CDC website on brucellosis