Infectious diseases


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José Antonio Zumalacárregui Ph.D.
Medically reviewed by our Medical staff

Last update: 24-03-2022

How else can it be called?

  • Malta fever

  • Undulant fever

  • Cyprus fever

  • Bang's disease

  • ICD-10: A23

What is brucellosis?

Brucellosis (also called Malta fever) is an Infection caused by bacteria belonging to the genus Brucella, found in cattle, swine, goats, and sheep.

Brucellosis typically causes flu-like symptoms, with recurrent episodes of fever, weakness, sweating and vague pain.

What are the main causes of brucellosis?

Brucellosis is caused by bacteria of the Brucella species found in the excrement and secretions of a wide variety of animals including cows, pigs, sheep and goats.

Brucella melitensis accounts for most cases, whereas Brucella abortus and Brucella suis are seen in a minority of cases.

Brucellosis is transmitted by consumption of unpasteurized milk from cows, sheep or goats or ingestion of unpasteurized dairy products (cheese, butter) that contain the microorganism.

It also transmitted by direct contact with infected animals and animal parts. It is considered an occupational hazard for people who work in the livestock sector or are in contact with animals such as farmers, butchers, hunters or veterinarians.

Human-to-human transmission is very rare.

Which is the clinical course?

The incubation period of the disease can be highly variable, ranging from 5 days to several months (with an average of 2 weeks).

The most common signs and symptoms are:

  • Fever and chills, especially in late afternoon or evening.
  • Severe headache.
  • Joint and muscle pain.
  • Constipation.
  • Loss of appetite, weight loss and weakness.
  • Enlargement of the spleen (splenomegaly), liver (hepatomegaly), and lymph nodes.

Fever in brucellosis patients can be intermittent and described as undulant fever. Undulant fever may last for weeks. The febrile phase recurs in waves with a tendency for remissions and recurrences for months.

How can it be diagnosed?

The standard procedures for diagnosis of brucellosis are:

  • Brucella agglutination test: It can detect antibodies to Brucella species. It is useful when it is clearly positive (values >1/160).
  • Culture: Diagnosis is definitive when Brucella organisms are recovered from blood, bone marrow, or other tissue.

What is the recommended treatment?

The recommended treatment combines different antibiotics for several weeks or months to eradicate the bacteria and prevent relapses.

The most common option is the combination of tetracycline (such as doxycycline) and streptomycin. Rifampin or gentamicin are also used.

What are the possible complications?

Patients with uncomplicated acute brucellosis usually recover completely in 2 or 3 weeks and complications are rare:

The most common complications are:

How can it be prevented?

The following measures are recommended to prevent the transmission of brucellosis:

  • Pasteurization of milk and dairy product (cheese, etc.) for consumption.
  • People who handle animal carcasses should wear safety glasses/goggles and rubber gloves to prevent transmission from animals to humans.
  • Elimination of infected animals and vaccination of cattle, goats and sheep in areas with high prevalence rates.
Medically reviewed by our Medical staff on 24-03-2022


  • Diagnostic Pathology of Infectious Disease. 2nd edition. Richard L. Kradin. 2018. ISBN: 978-0-323-44585-6. Pág. 294.
  • Microbiology. A Systems Approach. Marjorie Kelly Cowan, Heidi Smith. 5th edition. 2018. Pag 590. ISBN 978-1-259-70661-5.
  • Brucellosis. World Health Organization. Available on:

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