Brucellosis: Causes, Risk Factors, Symptoms, Treatment


Brucellosis is a bacterial infection caused by different strains of Brucella bacteria. It mainly affects the livestock and then transmitted to humans when a person comes into contact with infected cattle, sheep, goat, swine, horses or pigs. It is a notifiable disease. Brucella is highly contagious and spreads very easily among the cattle as the calf membranes and uterine fluids all contain large quantities of bacteria.

If you experience prolonged fever, joint pain, or flu-like symptoms, especially if you work with livestock or consume unpasteurized dairy, consult with an Infectious Disease specialist or a General Practitioner in the Internal Medicine department to explore the possibility of Brucellosis.


Brucellosis, a bacterial infection primarily caused by species of Brucella, spreads through contact with infected animals or consumption of contaminated animal products. Here are key points on its causes:

Animal Contact: Direct exposure to infected animals (cattle, goats, pigs, etc.) or their fluids (especially during birthing or abortion).

Consumption: Ingesting unpasteurized dairy products from infected animals.

Occupational Hazards: Veterinarians, farmers, and slaughterhouse workers are at higher risk due to frequent animal contact.

Laboratory Exposure: Accidental exposure in laboratories handling Brucella cultures.

Airborne Transmission: Rarely, airborne transmission in laboratories or slaughterhouses.

Vertical Transmission: Infected mothers can transmit the bacteria to their babies during birth or breastfeeding.

Prevention involves vaccination of livestock, pasteurization of dairy products, and protective measures for at-risk individuals.

Risk Factors

  • Occupational Exposure: Farmers, veterinarians, and slaughterhouse workers are at higher risk due to close contact with infected animals.
  • Consumption of Unpasteurized Dairy Products: Drinking raw milk or eating unpasteurized cheese increases the risk of infection.
  • Travel to Endemic Areas: Visiting regions where brucellosis is prevalent raises the likelihood of exposure.
  • Laboratory Exposure: Researchers handling Brucella bacteria are at risk of accidental exposure.
  • Consumption of Undercooked Meat: Eating undercooked meat from infected animals can transmit the bacteria.
  • Hunting or Butchering Infected Animals: Hunters and those handling meat from infected wild animals are susceptible.
  • Poor Hygiene Practices: Not washing hands after handling animals or animal products can lead to infection.

These factors highlight the importance of preventive measures such as vaccination of livestock and safe food handling practices to reduce the risk of brucellosis.


Brucellosis, also known as undulant fever or Malta fever, is a bacterial infection primarily caused by species of the genus Brucella. The symptoms can vary widely in severity and duration, depending on the individual and the strain of bacteria involved. Here are the key symptoms typically associated with brucellosis:

Fever: Often the first sign, with temperatures fluctuating between mild and high-grade fevers.

Sweats: Profuse sweating, especially at night.

Fatigue: Persistent weakness and fatigue, even after adequate rest.

Joint and muscle pain: Aches and pains in joints, muscles, and back, which can become chronic.

Headache: Often severe and recurrent.

Chills: Shivering and feeling cold, alternating with feverish sensations.

Loss of appetite: Reduced desire to eat, leading to weight loss.

Gastrointestinal symptoms: These may include nausea, vomiting, abdominal pain, and diarrhea.

Enlarged spleen and liver: In some cases, these organs may become enlarged (hepatosplenomegaly).

Neurological symptoms: Less commonly, brucellosis can cause neurological symptoms such as meningitis or depression.

Reproductive system complications: Infection may affect the reproductive organs, leading to symptoms like testicular inflammation or miscarriage in pregnant women.

Heart-related complications: Rarely, the infection can affect the heart, causing endocarditis.

Brucellosis symptoms can persist for weeks to months if untreated and may recur or become chronic. Prompt diagnosis and appropriate antibiotic treatment are crucial to prevent complications and reduce the duration of illness.

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Diagnosis of Brucellosis involves a combination of clinical evaluation, laboratory tests, and sometimes imaging studies. Here are the key points:

Clinical Presentation: Symptoms include fever, sweats, malaise, and muscle pain, which can mimic other febrile illnesses.

Risk Factors: History of exposure to infected animals or consumption of unpasteurized dairy products.

Laboratory Tests:

  • Serology: Detects antibodies (IgM and IgG) against Brucella species.
  • Blood Cultures: Identifies Brucella bacteria in blood samples, though it can take up to 2-4 weeks for results.
  • PCR (Polymerase Chain Reaction): Detects Brucella DNA directly, providing a rapid diagnostic method.

Imaging: X-rays or MRI may reveal signs of osteoarticular involvement or other complications in chronic cases.

Differential Diagnosis: Includes other febrile illnesses such as malaria, typhoid fever, and tuberculosis.

Consultation: Infectious disease specialists for guidance on management and treatment.

Early diagnosis is crucial to prevent complications and ensure appropriate treatment with antibiotics like doxycycline and rifampin.


Treatment of brucellosis typically involves a combination of antibiotics to effectively eradicate the bacteria.

Antibiotics: The primary treatment involves a prolonged course (typically 6 weeks to several months) of antibiotics such as doxycycline and rifampin. Alternatives include trimethoprim-sulfamethoxazole or fluoroquinolones.

Combination Therapy: Two or more antibiotics are often used simultaneously to prevent relapse and reduce the risk of developing antibiotic resistance.

Monitoring: Regular follow-up visits and laboratory tests are crucial to monitor treatment response and detect any complications.

Symptomatic Relief: Medications for pain, fever, and other symptoms may be prescribed to alleviate discomfort.

Rest and Hydration: Adequate rest and hydration are important to support recovery and reduce symptoms.

Avoidance of Raw Dairy: Patients should avoid consuming raw dairy products to prevent further exposure.

Prevention: In endemic areas, preventive measures include vaccination of animals and proper food hygiene practices.

Preventive Measures

Preventing brucellosis involves several key measures to reduce the risk of transmission. Here are some preventive measures:

Vaccination: Vaccinating livestock, particularly cattle, goats, and sheep, helps prevent the spread of brucellosis among animals.

Control of Animal Movement: Restricting the movement of infected animals and quarantining newly introduced animals can prevent the spread of the disease within herds.

Proper Hygiene Practices: Practicing good hygiene when handling animals or animal products, including wearing gloves and washing hands thoroughly, reduces the risk of transmission.

Consuming Pasteurized Dairy Products: Ensuring dairy products are pasteurized before consumption minimizes the risk of contracting brucellosis from contaminated milk or cheese.

Awareness and Education: Educating farmers, veterinarians, and the public about the symptoms, transmission routes, and preventive measures can help in early detection and control of the disease.

Regular Testing: Periodic testing of livestock for brucellosis helps in early identification and containment of infected animals.

Personal Protection Equipment: Using appropriate personal protective equipment (PPE) when handling potentially infected animals or tissues further reduces the risk of transmission.

Do's & Don’t's

Do's Don't 
Be aware of brucellosis symptoms and seek medical attention if exposed to the bacteria.  Do not neglect the seriousness of the illness; seek medical attention promptly. 
No special diet is required during brucellosis treatment.  Do not self-medicate based on symptoms; consult a healthcare professional for proper treatment. 
Avoid consuming raw or under-cooked meat.  Consume unpasteurized dairy products, Neglect proper cooking practices for meat.
Take precautions to ensure that milk is boiled to a high temperature for a certain period.  Ignore the importance of pasteurization, Underestimate the impact of brucellosis on health.

If you experience prolonged fever, joint pain, or flu-like symptoms, especially if you work with livestock or consume unpasteurized dairy, consult with an Infectious Disease specialist or a General Practitioner in the Internal Medicine department to explore the possibility of Brucellosis.

Frequently Asked Questions
Brucellosis is a bacterial infection caused by various species of the Brucella bacteria. It primarily affects animals but can be transmitted to humans through direct contact with infected animals or consumption of unpasteurized dairy products.
Humans can contract brucellosis through contact with infected animals, consuming contaminated dairy products, inhalation of airborne particles, or exposure to infected tissues or fluids.
Symptoms can include fever, sweats, malaise, joint and muscle pain, fatigue, headache, and in severe cases, organ involvement like the liver, spleen, or heart.
Diagnosis involves blood tests, cultures, or other laboratory tests to detect the presence of Brucella bacteria or antibodies.
Antibiotics, typically a combination of antibiotics, are used to treat brucellosis. The course of treatment can be lengthy, and it's important to complete the prescribed medication regimen.
Preventive measures include practicing good hygiene when handling animals, consuming only pasteurized dairy products, wearing protective gear when in contact with potentially infected animals or tissues, and vaccination of animals in endemic areas.
Human-to-human transmission is rare, but it can occur through blood transfusions, organ transplants, or from an infected mother to her unborn child during pregnancy.
People who work closely with animals such as veterinarians, farmers, slaughterhouse workers, and laboratory personnel handling infected materials are at a higher risk.
Brucellosis is widespread in many parts of the world and poses a significant economic burden due to its impact on animal health, decreased productivity, and potential human infections.
Chronic brucellosis can lead to complications affecting the bones, joints, heart, and other organs if not treated promptly and adequately.
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