Brucellosis

Nature of the disease

Brucellosis is a bacterial infection that spreads from animals to people, most often via unpasteurized milk, cheese, other dairy products and undercooked meat from infected animals, or close contact with their secretions.  More rarely, the bacteria that cause brucellosis can spread through the air or through direct contact with infected animals.  It is associated with fever, joint pain and fatigue.

Causative agents

Brucellosis affects many wild and domestic animals. Cattle, goats, sheep, pigs, dogs, camels and wild boar are especially prone to the disease. The bacteria may be spread from animals to people in three main ways:

1. Raw dairy products: Brucella bacteria in the milk of infected animals can spread to humans in unpasteurized milk, ice cream, butter and cheeses. The bacteria can also be transmitted in raw or undercooked meat from infected animals.
2. Inhalation: Brucella bacteria spread easily in the air. Farmers, laboratory technicians and slaughterhouse workers can inhale the bacteria.
3. Direct contact: Bacteria in the blood, semen or placenta of an infected animal can enter your bloodstream through a cut or other wound. Because normal contact with animals — touching, brushing or playing — doesn’t cause infection, people rarely get brucellosis from their pets. Even so, people with weakened immune systems should avoid handling dogs known to have the disease.

Brucellosis normally doesn’t spread from person to person, but there have been some very few cases, women passing the disease to their infants during birth or through their breast milk. Rarely, brucellosis may spread through sexual activity or through contaminated blood or bone marrow transfusions.

Clinical features

Brucellosis presents different non-specific clinical manifestation such as fever, sweats, malaise, anorexia, headache, back pain as well as substantial residual disability.

Signs and symptoms

Signs and symptoms of brucellosis may show up anytime from a few days to a few months after an individual is infected. Signs and symptoms are similar to those of the flu and include:

1. Fever
2. Chills
3. Loss of appetite
4. Sweats
5. Weakness
6. Fatigue
7. Joint, muscle and back pain
8. Headache

Brucellosis signs and symptoms may disappear for weeks or months and then return. In some people, brucellosis becomes chronic, with symptoms persisting for years, even after treatment. Long-term signs and symptoms may include fatigue, recurrent fevers, arthritis and swelling of the heart.

Diagnosis of brucellosis

Brucellosis is diagnosed by testing a sample of blood or bone marrow for the brucella bacteria or by testing blood for antibodies to the bacteria. To help detect complications of brucellosis, other additional tests, including:

1. X-rays: X-rays is used to reveal changes in the bones and joints.
2. Computerized tomography (CT) scan or magnetic resonance imaging (MRI): These imaging tests help to identify inflammation in the brain or other tissues.
3. Cerebrospinal fluid culture: This checks a small sample of the fluid that surrounds the brain and spinal cord for infections such as meningitis.
4. Echocardiography: This test uses sound waves to create images of the heart to check for signs of infection or damage to the heart.

Incubation period of brucellosis

The incubation period is highly variable, usually 2-4 weeks, can be 1 week to 2 months or longer.

Treatment of brucellosis

Treatment for brucellosis aims to relieve symptoms, prevent a relapse of the disease and avoid complications. This is done through the use of antibiotics for at least six weeks, and the symptoms may not go away completely for several months. The disease can also return and may become chronic.

Preventive measures for brucellosis

To reduce the risk of getting brucellosis, the following preventive measures are very important:

• Avoid unpasteurized dairy foods: Cases of brucellosis have been linked to raw dairy products from domestic herds. So it is probably best to avoid unpasteurized milk, cheese and ice cream, no matter what their origin.
• Cook meat thoroughly: Cook all meat until it reaches an internal temperature of 63 to 74 C. When eating out, order beef and pork at least medium-well.
• Wear gloves: For veterinarians, farmers, hunters or slaughterhouse workers, wear rubber gloves when handling sick or dead animals or animal tissue or when assisting an animal giving birth.
• Take safety precautions in high-risk workplaces: Laboratory workers, should handle all specimens under appropriate biosafety conditions. Treat all workers who have been exposed promptly. Slaughterhouses should also follow protective measures, such as separation of the killing floor from other processing areas and use of protective clothing.
• Vaccinate domestic animals