Brucellosis is a zoonotic disease that was first described in the era of Hippocrates, the father of medicine, and continues even today. Read and know all about this disease, including all possible causes, symptoms, diagnosis, treatment options and preventive measures.

Brucellosis Definition

It refers to an infectious disorder that arises as a result of contact with animals that carry the Brucella bacteria. It spreads from animals to humans, most frequently through cheese, pasteurized milk and other dairy products. The disease affects many wild and domestic animals as well as people who are in cloe contact with them.

The condition is also referred to by various other names, such as:

  • Bang’s disease
  • Cyprus fever
  • Gibraltar fever
  • Malta fever
  • Mediterranean fever
  • Rock fever
  • Undulant fever
  • Mediterranean gastric remittent fever

Brucellosis ICD9 Code

The ICD9 Code for this disease is 023.

Brucellosis Symptoms

The signs and symptoms of this infectious condition may arise at anytime ranging from a few days to a few months after being infected. The symptoms resemble that of flu and generally include the following:

  • Chills
  • Fever
  • Fatigue
  • Sweats
  • Headache
  • Weakness
  • Pain in the muscles, joint and back

The problems may go away for several weeks or months before reappearing all of a sudden. The condition turns chronic in some patients and the symptoms may persist for a number of years even after treatment.

The long-term symptoms of the disease include problems like:

  • Arthritis
  • Fever
  • Spondylitis, an inflammatory form of arthritis that affects the spine and the neighboring joints

The condition can be difficult to detect, especially in the early stages, when its symptoms resemble that of flu. Naturally it is important to visit a doctor in case of a rapidly rising fever, abnormal fatigue, muscle aches or any other problems associated with Brucellosis.

Brucellosis Epidemiology

The incidence of this condition is higher in agrarian societies. In the USA, it has a reported frequency of 0.04 in every 100,000 individuals. It is rare in inhabitants of UK although those travelling from endemic regions should always be suspected to be having it.

High-risk regions for this disorder include:

  • Middle East
  • Italy
  • Southern France
  • Portugal
  • Turkey
  • Greece
  • Spain
  • North Africa

Brucellosis Causes

As aforementioned, the condition is caused by a bacterial infection. This is a zoonotic disorder, meaning it is an animal disease that can be transmitted to human beings. The bacteria of genus Brucella is responsible for this disorder.

In humans, the condition is caused by four types of Brucella bacteria. These are:


It is responsible for the majority of cases of Brucellosis and is most frequently observed in areas like Greece, Spain, India, Latin America and Persian Gulf region among others.


It is the most common form of Brucella bacteria that is observed in the United States. It is carried by pigs and is mostly reported in the Midwest, followed by other areas like Southeast Asia and South America.


Brucellosis due to this form of Brucella spreads from dogs and is most frequently reported in countries like North America, South America, Japan and Central Europe.


It is spread from cattle and is globally reported. It has been eliminated in various European nations, Israel and Japan.

The Brucella bacteria can spread from animals to humans through any of the following ways:

Consumption of contaminated or infected food

Ingestion of infected food products such as untreated milk and other dairy products (mainly unpasteurized cheese), liver or raw meat can lead to a development of this disease.

Inhalation of aerosols

This is the most common mode of transmission in endemic regions and affects herdsmen, farmers, abattoir workers, lab technicians and families that share habitation with animals.

Skin or mucous membrane contact

Vets, lab technicians and hunters are some of the individuals who are commonly infected through this mode of transmission.

Person to person transmission

This can occur through breast-feeding, bone marrow transplantation, blood transfusion or sexual transmission. However, this type of transmission from one human to another is rare.

The bacteria responsible for this disease can also be spread through bioterrorism although Brucella is less likely to be chosen as an infectious agent due to the low mortality rate associated with it.

A form of the condition has also been found to affect porpoises, some whales and harbor seals. Coming in close contact with such types of marine infected animals can also make a person develop this disorder.

Brucellosis Risk Factors

The risk factors for this condition include:

Living in high-risk areas

Although Brucellosis is rare in the U.S, it is prevalent in various regions of the world such as areas around the Mediterranean Sea, close to the Persian Gulf, in Latin America and on the Indian subcontinent. Those who live in or travel to these regions are more likely to ingest village cheese, which is another name for unpasteurized goat cheese. This type of cheese, imported from Mexico, has also been linked to a number of cases of Brucellosis in the U.S.

Being engaged in high-risk professions

Those who are engaged in occupations that need them to come in close contact with animals or their infected blood are more susceptible to this disorder. Such people include:

  • Dairy farmers
  • Vets
  • Lab technicians
  • Microbiologists
  • Ranchers
  • Slaughterhouse workers

Brucellosis Diagnosis

The presence of this disorder is usually confirmed by physicians by testing a sample of bone marrow or blood, in order to determine the presence of the Brucella bacteria or for bacterial antibodies. Some additional tests may be deemed as necessary to help sufferers detect complications related with Brucellosis. These include:


These imaging exams are useful as they can show any changes in the bones and joints of the body of sufferers.

Magnetic Resonance Imaging (MRI) or Computerized tomography (CT) scans

These exams help detect abscesses or swelling in the brain or other tissues.

Cerebrospinal fluid culture

It helps analyze a small sample of the fluid surrounding the brain and spinal cord to determine the presence of infections such as Encephalitis and Meningitis.


This exam makes use of audio waves to produce images of the heart and look for signs or damages of infections in the heart.

Other assistive tests for this disease may involve:

  • Bone marrow culture
  • Clean catch urine culture
  • Serology for brucellosis antigen

The disorder may also change the results of the following exams:

  • Febrile/cold agglutinins
  • Serum immunoelectrophoresis
  • Quantitative immunoglobulins (nephelometry)

Brucellosis Differential Diagnosis

As the signs and symptoms of Brucellosis are non-specific in nature, they tend to be confused with those of many other disorders and agents. These include:

  • Bronchitis
  • Tuberculosis
  • Endocarditis
  • Pneumonia
  • Subarachnoid haemorrhage
  • Gastroenteritis
  • Osteomyelitis
  • Meningitis
  • Thrombocytopenic purpura
  • Urinary tract infection (UTI)
  • Biological warfare agents
  • Mechanical back pain

Physicians in charge of diagnosis must ensure that patients are not suffering from any of the above disorders and are in fact, having symptoms related with Brucellosis.

Brucellosis Treatment

In case of this disease, medical treatment has a three-fold aim:

  • To bring about relief from the discomforting symptoms
  • To prevent a relapse of the disorder
  • To prevent complications associated with this condition

Patients need to follow a course of antibiotic medications for a minimum period of six weeks as the symptoms may not completely resolve for several months. Antibiotics can cure the infection and also prevent the recurrence of the disease.

The condition may recur and even turn chronic in some cases. Longer courses of therapy may be required in case of complications.

Brucellosis Prognosis

The condition may relapse and the symptoms may persist for several years. As is the case with tuberculosis (TB), the disorder may recur after a long span of time. The majority of sufferers manage to have a complete recovery without complications, if they get appropriate antibiotic treatment.

The rate of relapse associated with this disease is around 10%, even with proper medical treatment. Death is rare, with an approximate mortality rate of 2%, and is generally related with Endocarditis.

Brucellosis Complications

The disorder can affect about any part of the human body, including the heart, liver, reproductive system and central nervous system. Chronic cases of Brucellosis may give rise to complications throughout the body or in only one organ.

The possible complications include the following:


Osteoarthritis and Spondylitis are two main arthritic complications associated with this disease. The former is characterized by stiffness, inflammation and pain in the joints, particularly in the ankles, spine, wrists, hips and knees. The latter is marked by swelling of the vertebral joints and can be specifically difficult to cure; it may result in lasting damage.

Central Nervous System (CNS) Infections

CNS infections include conditions like Meningitis and Encephalitis that can bring about the death of sufferers.


It is one of the most acute complications of Brucellosis. Untreated cases of this disorder can destroy or damage the cardiac valves; it is the primary cause of deaths associated with Brucellosis.

Brucellosis Prevention

The risk of acquiring this disease can be prevented by adapting the following preventive measures:

Wearing gloves while handling animals

Farmers, hunters, vets, slaughterhouse workers and other people who have to work with animals or their body should wear gloves while handling dead or infected animals or their tissue or while assisting animals at the time of giving birth.

Vaccinating domestic animals

Vaccinating domestic animals can reduce the risk of infection in them. An aggressive vaccination program in the U.S has been successful in almost wiping out Brucellosis in livestock herds.

Cooking meat thoroughly

Cooking meat of all domesticated animals at 145-165 F (63-74 C) is necessary before consumption. High heat is able to destroy all traces of bacteria present in meat products and make them safe to be eaten.


If you or any of your family members start showing one or more of the health problems associated to Brucellosis, get medical help on an immediate basis. Prompt diagnosis and treatment can keep the disease in check and prevent the occurrence of any possible complications in future. Timely cure can also ensure an early recovery from this discomforting disease.


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