10 Common Symptoms of Brucellosis: What You Need to Know

Brucellosis, also known as Malta fever or undulant fever, is a bacterial infection that spreads from animals to humans. This zoonotic disease is caused by Brucella bacteria and can affect various organs and systems in the body. While brucellosis is relatively rare in developed countries, it remains a significant health concern in many parts of the world, particularly in regions with livestock farming.

Understanding the symptoms of brucellosis in humans is crucial for early detection and proper medical care. The disease can present with a wide range of symptoms that may appear suddenly or develop gradually over weeks or months. Some people experience acute symptoms, while others develop chronic conditions that can last for years if left untreated.

Below are the 10 most common symptoms associated with brucellosis that you should be aware of:

1. Fever and Chills

One of the hallmark symptoms of brucellosis is recurrent fever, which often gives the disease its alternative name “undulant fever.” The fever pattern in brucellosis is distinctive and can help healthcare providers make a diagnosis.

The fever typically:

• Rises in the afternoon or evening
• Falls during the morning hours
• Ranges from 101°F to 104°F (38.3°C to 40°C)
• Comes and goes in waves over weeks or months

Patients often experience severe chills accompanying the fever, sometimes described as “teeth-chattering” chills. Night sweats are also common, often soaking through clothing and bedding. This cyclical fever pattern can be debilitating and significantly impact daily activities and quality of life.

2. Severe Fatigue and Weakness

Profound fatigue is one of the most disabling symptoms of brucellosis. This isn’t just ordinary tiredness; patients describe it as an overwhelming exhaustion that doesn’t improve with rest.

The fatigue associated with brucellosis:

• Interferes with normal daily activities
• Persists throughout the day
• May worsen during fever episodes
• Can continue for months even during treatment

Many patients report feeling completely drained of energy, making it difficult to perform even simple tasks. This extreme weakness can affect work performance, social activities, and overall well-being. The fatigue may be accompanied by general malaise and a feeling of being unwell that pervades every aspect of life.

3. Joint and Muscle Pain

Musculoskeletal symptoms are extremely common in brucellosis, affecting up to 70-80% of patients. These symptoms can be among the most painful and limiting aspects of the disease.

Joint involvement typically includes:

• Arthralgia (joint pain) in large joints such as knees, hips, and ankles
• Sacroiliitis (inflammation of the sacroiliac joint in the lower back)
• Spondylitis (inflammation of the vertebrae)
• Swelling and reduced range of motion in affected joints

Muscle pain (myalgia) is also prevalent, causing aching and soreness throughout the body. The back pain associated with brucellosis can be particularly severe and persistent. Some patients develop chronic arthritis if the infection is not treated promptly, leading to long-term joint damage and disability.

4. Headaches

Persistent headaches are a frequent complaint among people with brucellosis. These headaches can range from mild to severe and may significantly impact daily functioning.

Characteristics of brucellosis-related headaches include:

• Constant or intermittent pain
• Often described as a dull, throbbing sensation
• May worsen during fever spikes
• Can be accompanied by sensitivity to light

The headaches may be related to the systemic inflammatory response caused by the infection. In some cases, they can indicate more serious complications such as neurobrucellosis (when the infection affects the nervous system). Any severe or persistent headache, especially when accompanied by neck stiffness or altered mental status, requires immediate medical attention.

5. Excessive Sweating

Profuse sweating, particularly at night, is a characteristic symptom of brucellosis that can be extremely uncomfortable and disruptive to sleep.

The sweating pattern typically involves:

• Drenching night sweats that require changing clothes or sheets
• Sweating during fever episodes
• Sudden onset of perspiration without obvious cause
• Foul-smelling sweat in some cases

Night sweats can be so severe that patients wake up completely soaked, leading to poor sleep quality and increased fatigue. The excessive sweating can also cause embarrassment and social discomfort. This symptom often occurs in conjunction with the undulant fever pattern and may persist throughout the course of the illness.

6. Loss of Appetite and Weight Loss

Reduced appetite (anorexia) is common in brucellosis and often leads to unintentional weight loss. This symptom can contribute to the overall weakness and fatigue experienced by patients.

Appetite and weight changes may include:

• Complete loss of interest in food
• Early satiety (feeling full quickly)
• Nausea that interferes with eating
• Significant weight loss over weeks or months

The combination of reduced food intake and the body’s increased metabolic demands from fighting the infection can lead to substantial weight loss. Some patients report losing 10-20 pounds or more during the acute phase of the illness. This weight loss can further compromise the immune system and delay recovery, making nutritional support an important aspect of overall care.

7. Abdominal Pain and Digestive Issues

Gastrointestinal symptoms occur in approximately 50-70% of brucellosis cases. The bacteria can affect various organs in the abdomen, leading to diverse digestive complaints.

Common abdominal symptoms include:

• Pain or discomfort in the upper right abdomen
• Nausea and vomiting
• Diarrhea or constipation
• Enlarged liver (hepatomegaly) or spleen (splenomegaly)

The abdominal pain may be constant or cramping in nature. Hepatosplenic involvement is particularly common in brucellosis, and patients may notice tenderness or a feeling of fullness under the right rib cage (liver) or left rib cage (spleen). In some cases, the spleen can become significantly enlarged and palpable. Rarely, complications such as liver abscesses or splenic rupture can occur, though these are more common in untreated or severe cases.

8. Enlarged Lymph Nodes

Lymphadenopathy, or swollen lymph nodes, is a common finding in brucellosis as the immune system responds to the bacterial infection.

Lymph node involvement typically presents as:

• Palpable, tender lymph nodes
• Most commonly in the neck, armpits, or groin
• Usually multiple nodes are affected
• Nodes may be firm but movable

The enlarged lymph nodes are a sign that the body’s immune system is actively fighting the infection. They may be mildly tender to touch and can vary in size from pea-sized to larger nodules. Unlike some other infections, the lymph nodes in brucellosis rarely become suppurative (filled with pus) or break down. The lymphadenopathy usually resolves as the infection is treated, though it may persist for some time even after successful therapy.

9. Respiratory Symptoms

Although less common than other symptoms, respiratory complaints can occur in brucellosis, particularly when the infection affects the lungs or chest cavity.

Respiratory manifestations may include:

• Persistent dry cough
• Chest pain or discomfort
• Shortness of breath
• Pleuritic pain (sharp pain when breathing deeply)

Pulmonary brucellosis can present with various manifestations, including bronchitis, pneumonia, lung nodules, or pleural effusion (fluid around the lungs). Some patients develop a chronic cough that doesn’t respond to typical cough remedies. The respiratory symptoms can be particularly concerning when accompanied by fever and may be mistaken for other respiratory infections. A chest X-ray or CT scan may reveal abnormalities that help in diagnosis.

10. Neurological and Psychological Symptoms

Neurobrucellosis, though occurring in only 5-10% of cases, represents a serious complication where the bacteria affect the nervous system. Even without direct nervous system involvement, patients may experience various neurological and psychological symptoms.

These symptoms can include:

• Depression and mood changes
• Irritability and anxiety
• Difficulty concentrating and memory problems
• Sleep disturbances and insomnia
• In severe cases: meningitis, encephalitis, or nerve inflammation

Many patients with brucellosis report feeling mentally foggy or having difficulty with cognitive tasks they could previously perform easily. The chronic nature of the illness, combined with persistent symptoms like fatigue and pain, can lead to significant psychological distress. Depression is common and may require supportive care. In cases of neurobrucellosis, more serious symptoms such as confusion, seizures, weakness, numbness, or changes in vision may occur, requiring urgent medical attention.

Main Causes of Brucellosis

Understanding how brucellosis is transmitted is essential for prevention. The disease is caused by several species of Brucella bacteria, primarily affecting humans through contact with infected animals or consumption of contaminated products.

Direct Contact with Infected Animals

The most common transmission route is direct contact with infected livestock or wildlife. Brucella bacteria can enter the body through breaks in the skin, mucous membranes, or conjunctiva (eyes). People at highest risk include:

• Farmers and ranchers who handle cattle, goats, sheep, or pigs
• Veterinarians and veterinary technicians
• Slaughterhouse workers and meat processors
• Hunters who handle wild game such as bison, elk, or wild pigs
• Laboratory workers handling Brucella cultures

Consumption of Contaminated Food Products

Ingestion of unpasteurized dairy products is a major source of human brucellosis, particularly in regions where raw milk consumption is common. Contaminated products include:

• Raw (unpasteurized) milk from infected cows, goats, or sheep
• Soft cheeses made from raw milk
• Ice cream or yogurt made from unpasteurized milk
• Undercooked meat from infected animals

Inhalation of Contaminated Aerosols

Breathing in bacteria-containing particles can cause infection. This route is particularly relevant for:

• Workers in slaughterhouses or meat-packing facilities
• Laboratory personnel working with Brucella cultures
• People present during animal birthing, especially in enclosed spaces
• Agricultural workers handling contaminated dust or soil

Geographic and Environmental Factors

Brucellosis is more prevalent in certain regions of the world where the disease is endemic in livestock populations. High-risk areas include:

• Mediterranean countries (Southern Europe)
• Middle Eastern countries
• Parts of Central and South America
• Central and Southeast Asia
• Sub-Saharan Africa

Prevention Strategies

Preventing brucellosis requires a combination of personal protective measures, food safety practices, and animal disease control. Here are key prevention strategies:

Food Safety Practices

• Avoid unpasteurized dairy products: Only consume milk, cheese, and other dairy products that have been pasteurized, especially when traveling to areas where brucellosis is common
• Cook meat thoroughly: Ensure all meat is cooked to safe internal temperatures (at least 160°F or 71°C for ground meat)
• Practice food hygiene: Wash hands before and after handling raw meat, and prevent cross-contamination in the kitchen

Occupational Safety Measures

• Use protective equipment: Wear gloves, masks, and protective clothing when handling animals, animal products, or potentially contaminated materials
• Practice good hygiene: Wash hands thoroughly with soap and water after animal contact
• Avoid direct contact: Minimize contact with animal birth products, blood, and reproductive organs
• Ensure proper ventilation: Work in well-ventilated areas to reduce aerosol exposure risk
• Follow laboratory safety protocols: Use appropriate biosafety measures when handling Brucella cultures

Animal Disease Control

• Vaccination programs: Support livestock vaccination initiatives in your area
• Testing and culling: Participate in animal testing programs and remove infected animals from herds
• Quarantine procedures: Isolate new or sick animals before introducing them to existing herds
• Veterinary care: Ensure regular veterinary check-ups for livestock

Travel Precautions

• Be aware of endemic areas: Research brucellosis prevalence in your travel destination
• Avoid risky foods: Be especially cautious about dairy products and undercooked meat in high-risk regions
• Minimize animal contact: Limit direct contact with livestock or wildlife in endemic areas

For High-Risk Individuals

People in high-risk occupations should:

• Receive regular health screenings and monitoring
• Be educated about brucellosis symptoms and transmission
• Report any potential exposure to healthcare providers immediately
• Consider career counseling if pregnant or immunocompromised, as these conditions increase risk of severe disease

Frequently Asked Questions

How long does it take for brucellosis symptoms to appear?

The incubation period for brucellosis typically ranges from 1 to 4 weeks after exposure, though it can sometimes take several months. Symptoms may develop suddenly (acute form) or gradually over time (insidious onset). The variable incubation period can make it challenging to identify the source of infection.

Can brucellosis be transmitted from person to person?

Person-to-person transmission of brucellosis is extremely rare. However, it has been documented in a few cases through sexual contact, breastfeeding, tissue transplantation, and blood transfusion. The primary transmission route remains through infected animals or contaminated animal products, not human contact.

How is brucellosis diagnosed?

Brucellosis is diagnosed through a combination of clinical evaluation and laboratory tests. Blood tests can detect Brucella antibodies or isolate the bacteria through blood cultures. Additional tests may include bone marrow cultures, imaging studies (X-rays, CT scans), or tissue biopsies depending on symptoms. A detailed history of animal exposure or consumption of unpasteurized dairy products helps support the diagnosis.

Can brucellosis symptoms come back after treatment?

Yes, brucellosis can relapse even after appropriate treatment. Relapse rates range from 5-15% and typically occur within the first six months after completing treatment. Symptoms that return may be milder than the initial infection. This is why follow-up care and monitoring are essential. If symptoms recur, consult your healthcare provider immediately for re-evaluation.

Who is most at risk for developing brucellosis?

High-risk groups include farmers, ranchers, veterinarians, slaughterhouse workers, meat processors, dairy workers, hunters, and laboratory personnel who work with Brucella. People who consume unpasteurized dairy products or undercooked meat from infected animals are also at risk. Travelers to regions where brucellosis is endemic face increased risk, particularly if they consume local dairy products.

Is brucellosis a serious disease?

While brucellosis is rarely fatal, it can cause severe, debilitating symptoms and serious complications if left untreated. The disease can become chronic and last for years, significantly impacting quality of life. Complications can affect the heart (endocarditis), nervous system (neurobrucellosis), bones and joints (osteoarticular brucellosis), and other organs. Early diagnosis and appropriate medical care are crucial for preventing chronic infection and complications.

How long does brucellosis last?

The duration of brucellosis varies widely. Acute brucellosis typically lasts a few weeks to months with appropriate treatment. Without treatment, symptoms can persist for months or even years, potentially becoming chronic. Some patients experience a relapsing-remitting pattern with symptoms that come and go over extended periods. With proper medical care, most people recover fully, though some may experience prolonged fatigue and other symptoms even after successful treatment.

Can brucellosis affect pregnancy?

Yes, brucellosis during pregnancy can have serious consequences including miscarriage, premature delivery, and intrauterine infection. Pregnant women who suspect brucellosis should seek immediate medical attention. The infection can also be transmitted to newborns during delivery or through breastfeeding. Special considerations for treatment are necessary during pregnancy, and your healthcare provider will need to balance the risks and benefits of different therapeutic approaches.

References:

• Centers for Disease Control and Prevention (CDC) – Brucellosis
• World Health Organization (WHO) – Brucellosis Fact Sheet
• Mayo Clinic – Brucellosis
• NHS – Brucellosis
• MedlinePlus – Brucellosis