Infectious agent: Brucella species (Brucella melitensis, Brucella suis, Brucella abortus, Brucella canis, and others)
Description of illness: Brucellosis is caused by a group of bacteria which infect various animal hosts. The primary hosts are cattle and bison (Brucella abortus), swine (B. suis), sheep and goats (B. melitensis), and dogs (B. canis). Brucella bacteria are found in blood, milk and reproductive organs of infected animals. Humans become infected by inhalation, contact with broken skin, or consuming unpasteurized dairy products or undercooked meat from infected animals. Symptoms generally appear within 5 to 60 days after exposure but may take up to a year. The predominant symptom is fever, often accompanied by chills, sweats and weakness. Other symptoms may include fatigue, headache, weight loss, joint pain, and enlarged lymph nodes, spleen and liver.