In the first stage of the disease, bacteremia occurs and leads to the classic triad of undulant fevers, sweating (often with a characteristic foul, moldy smell sometimes likened to wet hay), and migratory arthralgia and myalgia (joint and muscle pain).
People with brucellosis may develop fever, sweats, headaches, back pains, and physical weakness. In severe cases, the central nervous system and the lining of the heart may be affected. One form of the illness may also cause long-lasting symptoms, including recurrent fevers, joint pain, and fatigue.
Chronic brucellosis is treated with triple-antibiotic therapy. The combination of rifampin, doxycycline, and streptomycin often is used.
*Three types of the bacteria that cause brucellosis – Brucella abortus, Brucella melitensis and Brucella suis – are designated as select agents. This means that they have the potential to be developed as bioterrorism agents due to their ability to undergo aerosolization.
B. melitensis causes the most severe cases of brucellosis and is the most prevalent worldwide. B melitensis is acquired by exposure to animals or animal products.
Of the 4 Brucella species known to cause disease in humans (B abortus, B melitensis, B canis, B suis), B melitensis is thought to be the most virulent and causes the most severe and acute cases of brucellosis; it is also the most prevalent worldwide.
CDC utilizes a test called the Brucella microagglutination test (BMAT), a modified version of the serum (tube) agglutination test (SAT), that can detect antibodies to Brucella species – abortus, melitensis or suis.
Treatment and care
The incubation period of the disease can be highly variable, ranging from 1 week to 2 months, but usually 2–4 weeks. Treatment options include doxycycline 100 mg twice a day for 45 days, plus streptomycin 1 g daily for 15 days.
Generally, the antibiotics doxycycline and rifampin are recommended in combination for a minimum of 6-8 weeks.
Inflammation of the inner lining of the heart chambers (endocarditis). This is one of the most serious complications of brucellosis. Untreated endocarditis can damage or destroy the heart valves and is the leading cause of brucellosis-related deaths.
Involvement of the musculoskeletal system is the most common complication of brucellosis, while meningitis and endocarditis are life-threatening complications.
Brucellosis can also cause long-lasting or chronic symptoms such as recurrent fevers, joint pain, testicular swelling, heart infections, nervous system impairment, depression, and fatigue. Death from brucellosis is rare.
Brucellosis is caused by Brucella species, which are gram-negative bacteria. Symptoms begin as an acute febrile illness with few or no localized signs and may progress to a chronic stage with relapses of fever, weakness, sweats, and vague aches and pains. Diagnosis is by culture, usually from the blood.
The most frequently reported neuropsychiatric symptoms of brucellosis were headache, depression, and fatigue.
See a GP if you have symptoms of brucellosis and:
you've had unpasteurised milk or dairy products. you've eaten raw or undercooked meat. you work closely with farm animals.
Doctors usually confirm a diagnosis of brucellosis by testing blood or bone marrow for the brucella bacteria or by testing blood for antibodies to the bacteria. To help detect complications of brucellosis, your doctor may order additional tests, including: X-rays. X-rays can reveal changes in your bones and joints.
Brucella in animals cannot be cured. Brucellosis is rare in the U.S. because of effective animal disease control programs.
The test consists of mixing colored Brucella whole-cell antigen with fresh bulk/tank milk. In the presence of anti-Brucella antibodies, antigen-antibody complexes form and migrate to the cream layer, forming a purple ring on the surface. In the absence of antigen-antibody complexes, the cream remains colorless.
Brucellosis is an infectious disease caused by bacteria. People can get the disease when they are in contact with infected animals or animal products contaminated with the bacteria. Animals that are most commonly infected include sheep, cattle, goats, pigs, and dogs, among others.
The incubation period is usually 2–4 weeks (range, 5 days to 6 months). Initial presentation is nonspecific and includes fever, malaise, arthralgia, myalgia, fatigue, headache, and night sweats.
Brucellosis, also known as “undulant fever”, “Mediterranean fever” or “Malta fever” is a zoonosis and the infection is almost invariably transmitted by direct or indirect contact with infected animals or their products. It affects people of all age groups and of both sexes.
Brucellae are Gram-negative coccobacilli (short rods) measuring about 0.6 to 1.5 μm by 0.5-0.7 μm. They are non-sporing and lack capsules or flagella and, therefore, are non-motile.
Brucellosis can be diagnosed in a laboratory by finding bacteria in samples of blood, bone marrow or other bodily fluids. Serological tests can also be done to detect antibodies against the bacteria. Learn more about what can be done to help confirm diagnosis of this disease.