Definition

Brucellosis is a rare bacterial disease that causes intermittent fevers. Brucellosis is primarily passed among animals, but people can acquire this disease from domesticated animals. It results in flu-like]]> symptoms, and may cause long-lasting symptoms. There are only about 100 to 200 cases of brucellosis in humans in the US each year.

Causes

Brucellosis is caused by the bacterium Brucella. This bacterium infects domesticated animals. It can be spread to humans through:

• Drinking unpasteurized milk
• Eating dairy foods from infected cows, sheep, or goats
• Having direct contact with the secretions, excretions, or carcasses of infected animals
• Inhaling the bacteria
• Breastfeeding (passed from mother to infant)
• Sexual transmission
• Tissue transplantation

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition. Risk factors for brucellosis include:

• Eating or drinking unpasteurized dairy foods, especially when traveling
• Working with domesticated animals and livestock, especially sheep, goats, cattle, deer, elk, and pigs, or their excretions, secretions, or carcasses
• Sex: male (possibly due to occupational exposure among farmers, ranchers, veterinarians, people working in tanneries, and slaughterhouse workers)

Symptoms

Symptoms of brucellosis usually appear within two weeks of infection. Symptoms can appear from five days to several months after infection.

In early stage, symptoms may include:

• Malaise
• Lethargy
• Headache
• Muscle pain
• Fever
• Chills
• Severe headache and backache
• Nausea, vomiting, and diarrhea]]>

As it progresses, brucellosis causes a severe fever (104° F to 105° F). This fever occurs in the evening along with severe sweating. It becomes normal or near normal in the morning, and usually begins again at night.

This intermittent fever usually lasts 1 to 5 weeks, after which symptoms usually subside or disappear for two days to two weeks. Then the fever recurs. In some patients, this fever recurs only once. In others, the disease becomes chronic, and the fever recurs, subsides, and then recurs again repeatedly over months or years.

In later stages, brucellosis can cause:

• Loss of appetite
• Weight loss
• Abdominal pains
• Headache
• Backache
• Joint pain
• Weakness
• Irritability
• ]]>Insomnia]]>

Patients usually recover within 2 to 5 weeks. Rarely, complications can develop. These may include:

• Abscesses within the liver or spleen
• Enlargement of the liver, spleen, or lymph nodes
• Inflammation and infection of organs in the body, such as:
  • Heart ( ]]>endocarditis]]> )
  • Brain and brain lining ( ]]>meningitis]]> )
  • Bones ( ]]>osteomyelitis]]> ), especially the spine

Brucellosis is also believed to cause a high rate of ]]>miscarriage]]> during early pregnancy in infected women.

Diagnosis

Your doctor will ask about your symptoms and medical history, and perform a physical exam. Tests may include the following:

• Blood, urine, bone marrow, or tissue tests–to look for Brucella bacteria
• Blood test—to look for antibodies against the bacteria
• Imaging tests ( x-ray]]> , ]]>CT scan]]> , ]]>MRI scan]]> )—to reveal abscesses, calcifications, or enlargement of the liver, spleen, or vertebrae

Treatment

Many patients recover from brucellosis on their own. However, early diagnosis and treatment can reduce the risk of complications and infection. Talk with your doctor about the best treatment plan for you. Treatment options include:

Prevention

To help reduce your chances of getting brucellosis, take the following steps:

• Avoid eating or drinking unpasteurized milk and dairy foods. If you are unsure if a dairy product is pasteurized, don’t eat it.
• Wear rubber gloves and goggles, and securely cover open wounds when handling domesticated animals including their secretions, excretions, or carcasses.
• Wear a protective mask when dealing with brucellosis cultures in the laboratory.
• Have cattle and bison that live in areas heavily infected with brucellosis vaccinated by an accredited veterinarian or government health official (the vaccine contains a live virus and is dangerous to humans). For best results, calves should be vaccinated when they are 4-6 months old. There is no brucellosis vaccine for humans as of yet.