Understanding Brucellosis: Causes, Symptoms, Diagnosis, and Treatment

Creator: Doctronic
Published: 2023-11-10

Medically reviewed by Jerome Albert Ecker | MD, Assistant Professor of Medicine, Duke University - Durham, NC on November 10th, 2023.

Key Takeaways

This zoonotic infection spreads through four main routes: consuming unpasteurized dairy products, direct contact with infected animal fluids, inhaling contaminated aerosols, or rarely through person-to-person transmission.
Symptoms typically emerge 1-4 weeks after exposure, featuring characteristic afternoon fever spikes reaching 104°F, profuse night sweats, and severe lower back pain that can mimic other conditions.
High-risk groups include veterinarians, livestock workers, laboratory personnel, and travelers to Mediterranean countries, Latin America, and parts of Asia where the disease remains endemic.
Standard treatment requires dual antibiotic therapy—doxycycline 100mg twice daily plus rifampin 600-900mg daily for 6-8 weeks—with cure rates exceeding 95% when completed fully.
Without proper treatment, 10-15% of cases develop chronic complications affecting the heart valves, spine, or nervous system that can persist for years.

Brucellosis is a rare infectious disease caused by bacteria called Brucella. While it primarily affects animals, it can also spread to humans. In this article, we'll explore the causes, symptoms, diagnosis, treatment, and prevention of brucellosis to help you better understand this condition.

Understanding Brucellosis: Causes, Symptoms, Diagnosis, and Treatment

What Causes Brucellosis?

Brucellosis occurs when a person comes into contact with an animal or animal product infected with Brucella bacteria. The bacteria can enter the body through cuts in the skin, by breathing in contaminated air, or by consuming contaminated food or drink, such as unpasteurized milk or undercooked meat.

There are four main types of Brucella bacteria that cause human brucellosis:

B. melitensis (most common, found in sheep and goats)
B. suis (found in wild pigs)
B. canis (spread from dogs)
B. abortus (comes from cattle)

Risk Factors for Brucellosis

You are more likely to get brucellosis if you:

Consume unpasteurized dairy products from infected animals
Eat "village cheeses" from high-risk regions like the Mediterranean
Travel to areas where Brucella is common
Work in a meat-processing plant, slaughterhouse, or on a farm
Are a hunter or veterinarian

Symptoms of Brucellosis

Symptoms of brucellosis often resemble the flu and may include:

Fever (most common, with high "spikes" in the afternoon)
Back pain
Body-wide aches and pains
Poor appetite and weight loss
Headache
Night sweats
Weakness
Abdominal pain
Cough

Symptoms usually appear within 5 to 30 days after exposure to the bacteria. The severity of symptoms depends on the type of Brucella causing the infection.

Diagnosing Brucellosis

To diagnose brucellosis, your doctor will perform a physical examination and may find signs such as a swollen liver, swollen lymph nodes, a swollen spleen, unexplained fever, joint swelling, and pain. Blood tests will be done to confirm the infection and identify the specific type of Brucella responsible.

Treating Brucellosis

Brucellosis is treated with antibiotics, usually a combination of doxycycline and rifampin for 6-8 weeks. Other antibiotics that may be used include streptomycin, ciprofloxacin, ofloxacin, sulfamethoxazole/trimethoprim, and tetracycline. It's crucial to complete the full course of antibiotics to prevent the disease from returning.

Complications of Brucellosis

Severe brucellosis may lead to complications such as:

Infection of the central nervous system
Endocarditis (infection of the heart lining or valves)
Liver abscess
Long-lasting symptoms similar to systemic exertion intolerance disease (SEID)
Miscarriage or birth defects in pregnant women

While death from brucellosis is uncommon, most brucellosis-related deaths are due to endocarditis.

Preventing Brucellosis

To reduce your risk of brucellosis:

Avoid consuming unpasteurized dairy products
Wear rubber gloves if you work in the animal processing industry
Inform your healthcare provider if you have come in contact with an infected animal, even if you don't have symptoms

Currently, there is no effective human vaccine to prevent brucellosis.

For more information on brucellosis, visit:

The Bottom Line

Early recognition and completing the full antibiotic course is crucial since untreated cases can become chronic and cause serious organ damage. Anyone with prolonged fever, night sweats, and back pain after animal exposure should seek immediate medical evaluation. If you're experiencing these concerning symptoms, Doctronic can help you get properly diagnosed and treated quickly.