Brucellosis / Undulant fever is a bacterial disease transmitted directly or indirectly to humans from infected animals. Consumption of unpasteurized milk products or contact with animals is commonly the source of infection. Brucella bacteria infects cows, sheep, camels, goats & pigs. Symptoms include fever with night sweats, headache, backache and muscle pain. If pregnant women are infected, they can have a miscarriage. IgG antibodies appear later in the course of the disease but usually decline after treatment.