Brucellosis is a zoonotic disease (any disease or infection that is naturally transmissible from vertebrate animals to humans and vice-versa is classified as a zoonotic disease).
It is also known as “undulant fever”, “Mediterranean fever” or “Malta fever”.  Brucellosis is a disease of mainly cattle, swine, goats, sheep and dogs.
The infection can be easily transmitted to humans by animals through direct contact with infected materials like afterbirth or indirectly by ingestion of animal products and by inhalation of airborne agents.
Intake of raw milk and cheese made from raw milk (fresh cheese) is the major source of infection in man. It is also an occupational disease for people who work in the livestock sector. It affects people of all age groups and of both sexes.
Causes of Brucellosis
Brucellosis is caused by different species of bacteria Brucella such as Brucella abortus, Brucella melitensis, Brucella suis, Brucella canis. They are shed in large numbers in the urine, milk and placental fluid of infected animals.
The infection is transmitted to humans by animals through three different ways-
- Infection can occur with direct contact with infected materials like afterbirth, blood, urine through broken skin, mucus membrane or conjunctiva.
- Infection can take place indirectly by ingestion of animal products such as raw milk and cheese made from raw milk. It is the major source of infection in humans.
Brucella may last for longer periods in dust, dung, water, slurry, aborted fetuses, soil, meat and dairy products.
Diagnosis of Brucellosis
The clinical picture is not specific therefore diagnosis needs to be supported by laboratory tests.
- Rose Bengal test (RBT) can be done for screening positive tests to be confirmed by one of the tests
- Standard agglutination test (SAT).
- Isolation of Brucella spp. from blood or other clinical specimen.
- A laboratory diagnosis based on detection of agglutinating antibodies (RBT, SAT) combined with detection of non-agglutinating antibodies through:
- ELISA IgG test,
- Coombs IgG.
The simplest approach for preventing human brucellosis is the control and elimination of the infection in animals.
- Vaccination of cattle is suggested for control of bovine brucellosis in enzootic (constant presence of a disease in animal population) areas with high prevalence rates.
- Elimination by testing and culling is the way to the extraction of brucellosis in regions with a low prevalence.
People should be educated to avoid consuming unpasteurized milk and milk derivatives and to cook meat adequately.
Symptoms of Brucellosis
Initial symptoms of the disease include fever, weakness, malaise, anorexia, headache, pain in muscles and joint or back, fatigue.
Some signs and symptoms may persist for longer period are-
- Recurrent fever, arthritis, swelling of the testicle and scrotal area, swelling of the heart (endocarditis), chronic fatigue, depression, swelling of the liver or spleen.
Complications may affect any organ system.