Brucellosis
Everything about the causes, symptoms, and most effective treatment of Brucella infection.
Symptoms and causes
Brucellosis is an infectious disease caused by the bacterium Brucella, transmitted from animals to humans through the consumption of unpasteurized dairy products. Less commonly, infection can occur via inhalation or direct contact with an infected animal. It is also known as Malta fever because it was first described on this island in 1850.
The type of bacterium causing the disease varies depending on the host animal:
- Brucella melitensis: sheep and goats, less frequently cattle. It is the most common species causing infection in humans.
- Brucella abortus: cattle.
- Brucella suis: pigs and, occasionally, small ruminants and cattle.
Although recovery may take a long time, even months, the prognosis of brucellosis is good if appropriate treatment is followed.
Symptoms
The common symptoms of brucellosis include:
- Fever that rises and falls in waves: typically higher in the afternoon and lower in the morning, hence the name undulant fever.
- Chills
- Weakness
- Fatigue
- Hepatomegaly: enlarged liver
- Splenomegaly: enlarged spleen
- Cough
- Digestive disturbances
- Lymphadenopathy: abnormal size, consistency, or number of lymph nodes
Causes
Brucellosis infection may occur due to:
- Consuming raw or unpasteurized dairy products
- Eating raw or undercooked meat
- Contact with bodily fluids from infected animals
- Inhaling Brucella bacteria present in the air
In very rare cases, transmission can occur person-to-person through sexual contact, childbirth, or breastfeeding.
Risk Factors
Factors increasing the risk of brucellosis include:
- Consuming unpasteurized dairy products
- Drinking raw or undercooked milk or meat
- Occupations involving direct contact with live animals (farmers, veterinarians, dairy workers)
- Working in slaughterhouses
- Hunting
Complications
Although uncommon, brucellosis complications can be severe:
- Chronic brucellosis: persistent form where infection remains over a prolonged period
- Arthritis: inflammation and degeneration of the joints
- Sacroiliitis: inflammation of the joints connecting the sacrum and iliac bones
- Spondylitis: arthritis of the spine, more frequent in the lumbar region in brucellosis
- Endocarditis: inflammation of the endocardium, the inner lining of the heart
- Pericarditis: inflammation of the pericardium surrounding the heart
- Meningitis: inflammation of the meninges, the membranes surrounding the brain and spinal cord
- Encephalitis: inflammation of the brain, the main organ of the central nervous system
- Ocular infection
- Vasculitis: inflammation of blood vessels
Prevention
The best way to prevent brucellosis is to follow these recommendations:
- Consume pasteurized dairy products
- Properly cook milk and meat
- Avoid eating raw or undercooked meat
- Use gloves when handling or assisting animals
- Vaccinate animals against brucellosis
Which Doctor Treats Brucellosis?
Brucellosis is diagnosed and treated in the specialties of Internal Medicine or Infectious diseases.
Diagnosis
Brucellosis is diagnosed through blood or bone marrow analysis:
- Blood Culture: a blood sample is collected and cultured in the laboratory to detect or rule out Brucella. As the bacterium grows slowly, results may take up to 45 days.
- Bone marrow culture: a sample is taken from the pelvic bone and maintained under specific laboratory conditions to promote bacterial growth. It is more sensitive than blood culture and is typically performed to diagnose chronic brucellosis or confirm a negative blood culture result.
Imaging tests help assess potential organ damage.
Treatment
Brucellosis is treated with a combination of antibiotics, as the bacteria reside inside cells and are difficult to eradicate with a single drug. Doxycycline is usually the primary medication, while rifampicin, streptomycin, or gentamicin serve as secondary agents.
Treatment typically lasts about six weeks to ensure infection clearance and prevent recurrence. Symptoms may persist for several months, and regular follow-up is essential to detect relapse early.
