Brucellosis – Symptoms and Causes

What Is Brucellosis?

Brucellosis is a bacterial infection that spreads from animals to humans. It is most commonly transmitted by consuming unpasteurized milk, cheese, or other dairy products from infected animals.

Less commonly, it can spread through inhalation or direct contact with infected animals, especially in agricultural or laboratory settings.

Brucellosis is usually treated with antibiotics, but recovery can take weeks or even months. Brucellosis continues to affect people and animals around the world, particularly in regions with limited veterinary controls and food safety practices.

Signs and Warning Signs

Brucellosis symptoms can appear anywhere from a few days to several months after infection. The early warning signs often mimic flu-like symptoms, including:

• Fever
• Chills
• Sweating
• Weakness and fatigue
• Loss of appetite
• Muscle, joint, and back pain
• Headache

These symptoms may come and go, sometimes disappearing for weeks or months before returning. Some people develop chronic brucellosis, where symptoms persist for years even after treatment.

Long-term symptoms may include:

• Ongoing fatigue
• Fevers that come back repeatedly
• Endocarditis (inflammation of the heart’s inner lining)
• Various forms of arthritis affecting:
  • Joints
  • Spine (spondylitis)
  • Areas where the spine and pelvis connect (sacroiliitis)

When to See a Doctor

If you have a quickly rising fever, muscle aches, or unusual weakness along with any risk factors for brucellosis, contact your doctor. This disease can be difficult to identify early on because it often looks like the flu or other illnesses.

Don’t wait to seek medical help if you experience a fever that doesn’t go away. Early treatment can prevent more serious complications.

What Causes Brucellosis

Brucellosis affects a wide range of animals in the wild and on farms. The disease can infect cattle, goats, sheep, and pigs, as well as hunting dogs. Wild animals like deer, elk, bison, moose, and caribou can also carry the bacteria.

Even marine mammals such as harbor seals, porpoises, and certain whale species can be affected by a form of this disease.

The bacteria typically spread from animals to humans in three main ways:

1. Consuming Unpasteurized Dairy Products: The bacteria can live in the milk of infected animals and transfer to humans through raw milk, cheese, butter, and ice cream. Eating undercooked meat from infected animals also poses a risk.

2. Breathing in Contaminated Air: The bacteria travel easily through air. People at higher risk include:
   • Farmers
   • Hunters
   • Laboratory workers
   • Slaughterhouse employees

3. Direct Contact with Infected Animal Fluids: The bacteria can enter the human body through cuts or wounds when handling blood, semen, or placenta from infected animals.

Brucellosis rarely passes between humans. However, in some cases, infected mothers can transmit the disease to babies during birth or through breastfeeding. Very rarely, the disease may spread through sexual contact or contaminated blood transfusions.

Regular contact with pets generally doesn’t cause infection. However, people with weakened immune systems should avoid handling dogs known to have brucellosis.

Jobs with Higher Exposure

People in certain professions face greater chances of getting this disease due to their regular contact with animals or infected materials. These include:

• Animal doctors who treat sick livestock
• People working on dairy farms handling milk and animals
• Ranch workers managing cattle herds
• Workers in meat processing facilities
• Those who hunt wild animals
• Laboratory specialists studying bacteria

While the disease is uncommon in the United States, it appears more frequently in various global regions, including Southern European countries like Spain and Greece, parts of Eastern Europe, Mexico, countries throughout Asia, Africa, Caribbean islands, and Middle Eastern nations.

Health Problems

Brucellosis can spread throughout the body and cause several serious health issues. These problems may appear in just one area or affect multiple parts of the body.

Heart problems can occur when brucellosis causes endocarditis, which is inflammation of the inner lining of heart chambers. This dangerous complication can damage heart valves and is the main reason people die from brucellosis.

Joint inflammation is another common issue. People may experience pain, swelling, and stiffness in joints like knees, hips, ankles, and wrists.

When the infection affects the spine or the joints connecting the spine to the pelvis, it can be hard to treat and may cause permanent damage.

Men may develop inflammation of the testicles or epididymis (the tube connected to each testicle). This causes painful swelling that can be severe.

The liver and spleen can become infected and enlarged beyond their normal size.

Brucellosis can also infect the central nervous system, leading to:

• Meningitis (inflammation of the membranes around the brain and spinal cord)
• Encephalitis (brain inflammation)

These nervous system infections can be life-threatening if not treated properly.

Prevention

Brucellosis prevention focuses on several key strategies that can significantly reduce your risk of infection.

Food Safety Measures

Dairy products and meat require careful attention:

• Avoid Raw Dairy Products: Stay away from unpasteurized milk, cheese, and ice cream, especially when traveling internationally.
• Cook Meats Properly: Follow these temperature guidelines:
  • Whole cuts of meat: 145°F (63°C) with a 3-minute rest (medium)
  • Ground meat: 160°F (71°C) (well done)
  • All poultry: 165°F (74°C)

Occupational Protections

People working with animals should take extra precautions:

1. Use Protective Equipment: Always wear rubber gloves when handling sick or dead animals, animal tissues, or assisting with animal births.
2. Follow Workplace Safety Protocols: Laboratory workers should handle specimens under appropriate biosafety conditions.
3. Implement Slaughterhouse Safeguards: Separate killing floors from processing areas and use protective clothing.

Animal Health Management

Proper animal care helps prevent disease spread. Vaccinating domestic animals is critical for brucellosis control. In the United States, vaccination programs have nearly eliminated the disease in livestock herds.

However, the vaccine contains live bacteria that can cause human illness. Anyone experiencing an accidental needle stick during animal vaccination should seek immediate medical treatment.