Brucellosis is an infectious disease caused by the group Brucella. These are primarily passed among animals, and they cause disease in sheep, goats, cattle, deer, elk, pigs, dogs and several other animals. Humans become infected by coming in contact with animals or animal products that are contaminated with these germs.
Brucellosis is not very common in the United States, where 100 to 200 cases occur each year. But brucellosis can be very common in countries where animal disease control programs have not reduced the amount of disease among animals. Although brucellosis can be found worldwide, it is more common in countries that do not have good standardized and effective public health and domestic animal health programs.
Unpasteurized cheeses from countries that do not have good standardized and effective public health and domestic animal health programs represent a particular risk for tourists.
Humans are generally infected in one of three ways: eating or drinking something that is contaminated with Brucella, breathing in the organism (inhalation) or having the germs enter the body through skin wounds. The most common way to be infected is by eating or drinking contaminated milk products. When sheep, goats, cows, or camels are infected, their milk is contaminated with the bacteria. If the milk is not pasteurized, these bacteria can be transmitted to persons who drink the milk or eat cheeses made of it.
Inhalation of Brucella organisms is not common, but it can be a significant hazard for people in certain occupations, such as those working in laboratories or for slaughterhouse employees. Contamination of skin wounds may be a problem for persons working in slaughterhouses or meat packing plants or for veterinarians. Hunters may be infected through skin wounds or by accidentally ingesting the bacteria after cleaning deer, elk, moose or wild pigs that they have killed.
In humans, brucellosis can cause a range of symptoms that are similar to the flu and may include the following:
Brucellosis is diagnosed in a laboratory by finding Brucella organisms in samples of blood or bone marrow. Also, blood tests can be done to detect antibodies against the bacteria. If this method is used, two blood samples should be collected two weeks apart.
Doctors can prescribe effective antibiotics. Depending on the timing of treatment and severity of illness, recovery may take a few weeks to several months. Very few people die.