BRUCELLOSIS

also called Malta Fever, Mediterranean Fever, or Undulant Fever, infectious disease of humans and domestic animals characterized by the insidious onset of fever, chills, sweats, weakness, pains, and aches, all of which usually terminate within three to six months. The disease is named after the British army medical doctor David Bruce, who in 1887 first isolated and identified the causative bacteria from the spleen of a soldier who had died from the infection. Three main species of Brucella bacteria are the common cause of human disease, and the bacillus of each of the species has its major reservoir in domestic animals. The causative bacteria are Brucella melitensis (goats and sheep), Brucella suis (swine), and Brucella abortus (cattle). Brucellosis in animals results in severe economic losses to livestock owners. Brucellosis in cattle (which is also known as Bang's disease) may result in abortion, with subsequent loss of stock and lowered milk production; frequently, however, cows carry to term in spite of infection of uterine tissue. In swine, abortion is less common, even in cases in which the tissues of the sow are heavily infected. Brucellae are highly invasive microbes, causing the disease to spread rapidly from animal to animal. Infection of healthy animals takes place through the ingestion of contaminated food or by direct entrance of the brucellae through abrasions of the skin or through the mucous membrane of the eyes. In swine, infection of the genitalia of the boar can cause the disease to spread throughout the herd. Infected but healthy-appearing cattle, sheep, and goats can excrete considerable numbers of brucellae in their milk for months and, in some instances, for years. Humans contract brucellosis either directly or indirectly from infected animals. For reasons not clearly understood, children are more resistant than adults to brucellosis. The disease is very rarely transmitted from one human being to another. There is no dependable or practical form of drug therapy for animal brucellosis. To build up brucellosis-free herds, infected animals must be removed; vaccination of young animals is also a useful measure. Antibiotics are effective in treatment of the human disease in the acute stage. A combination of sulfonamide drug and streptomycin has proved to be successful, and therapy with tetracyclines, such as chlorotetracycline or oxytetracycline, has also given satisfactory results.