Brucellosis is a highly infectious bacterial disease that can transfer from species to species and occurs across the world. It is most common along the Mediterranean Coast, Middle East, India and in central South America, but since the first reported cases of brucellosis in Paju, Gyeonggi Province, in July 2002, the incidence has increased. The Infectious Diseases Prevention Act has named brucellosis a class 3 reportable disease, and bovine (cow) brucellosis is controlled as a class 2 infectious disease in domestic animals.

Brucellosis is caused by brucella, a bacterial microorganism that primarily causes chronic infection in cows, sheep, pigs and dogs. It can infect people through contact with feces from infected domestic animals, or the consumption of unsterilized milk, cheese or meat. The first reported cases of brucellosis in Korea were caused by drinking unpasteurized cow milk. 

A significant number of the following cases were veterinarians or those working with livestock, suggesting that the main route of infection is through contact with infected cows. The incidence of bovine brucellosis has increased significantly since the mid 1980s, which has led to the recent increase in the number of human brucellosis cases in Korea.

The latent period following infection is around one to four weeks. The symptoms of brucellosis vary widely and include fever, chills, sweating, headache, myalgia, arthralgia, lower back pain and weight loss. These symptoms can last anywhere between a few weeks to a few months, and if untreated, can last for years or recur. It can invade the central nervous system, the spine or the heart to cause serious complications.

A history of contact with infected animals or consumption of unpasteurized milk, cheese or ice cream in a person with unexplained and prolonged fever can be a hint to the diagnosis.

Brucellosis can be treated, but the treatment has a high rate of recurrence and failure. In addition, it requires a specialized program that consists of a combination of two types of antibiotics. The course of treatment is six weeks and sometimes longer for those with complications.

For prevention, it is important to avoid the consumption of milk, cheese and other dairy products made from unpasteurized milk, and immunize livestock. People visiting areas with high incidences of brucellosis should be careful to avoid consumption of such dairy products in order to prevent infection. 

By Chung Doo-ryeon

The author is a doctor in the Division of Infectious Diseases at Samsung Medical Center and a professor at Sungkyunkwan University School of Medicine. ― Ed.