Below you will find more information about Brucellosis from Medigest. If you believe that you are suffering from any of the symptoms of Brucellosis it is important that you obtain an accurate diagnosis from a medical professional to ensure that you obtain the correct medication or treatment for your condition. There are medical conditions that carry similar symptoms associated with Brucellosis and therefore the information provided by Medigest is offered as a guideline only and should never be used in preference to seeking professional medical advice. The information relating to Brucellosis comes from a third party source and Medigest will not be held liable for any inaccuracies relating to the information shown.


Brucellosis, also known as undulant fever, undulating fever, or Malta fever, is a zoonosis (infectious disease transmitted from animals to humans) caused by bacteria of the genus Brucella. It is generally a disease of domestic animals (goats, pigs, cattle, dogs, etc) and humans and has a worldwide distribution, mostly now in developing countries.


Prevalence of brucellosis varies across nations but obviously is higher in more agrarian societies and in places where handling of animal products and dairy products is less stringent. The highest incidence is observed in the Mediterranean region, Middle East, China, Peru, India, and Mexico. Currently, central and southwest Asia are seeing the highest increase in cases.


Brucellae are aerobic gram-negative coccobacilli that give out urease and catalyze nitrite to nitrate. They have a lipopolysaccharide coat that is lesser pyrogenic than other gram-negative organisms, which accounts for the rare presence of high fever in brucellosis. Brucellae can enter humans through breaks in the skin, mucous membranes, conjunctiva, and respiratory and GI tracts. Sexual transmission is not reported convincingly. Ingestion usually happens by way of unpasteurized milk, as meat products often have a low bacterial load. Percutaneous needlestick exposure, conjunctival exposure through eye splash, and inhalation are the most frequent routes in the United States. Both polymorphonuclear leukocytes and macrophages ingest brucellae, but the organism can stop fusion of phagosome and lysosome. Brucellae are transported into the lymphatic system and may mimic there locally; they also may replicate in the kidney, liver, spleen, breast tissue, or joints, causing both localized and systemic infection. Granulomas may go with extracellular replication of the bacteria, especially in the liver and spleen. The typical method of control is cell-mediated immunity rather than antibodies, although some immunity to reinfection is provided by serum immunoglobulins. Initially, immunoglobulin M (IgM) levels increase, followed by immunoglobulin G (IgG) titers. IgM may stay in the serum in low levels for several months, whereas IgG eventually declines. Persistently heightened IgG titers or second rises in IgG usually indicate chronic or relapsed infection.

Symptoms and Signs

Brucellosis leads to inconstant fevers, sweating, weakness, anemia, headaches, depression and muscular and bodily pain. The symptoms are similar to those associated with many other febrile diseases, but with emphasis on muscular pain and sweating. The duration of the disease can differ from a few weeks to many months or even years. In the initial stage of the disease, septicaemia occurs and leads to the classic triad of undulant fevers, sweating (often with characteristic smell, likened to wet hay) and migratory arthralgia and myalgia. This complex is, at least in Portugal, referred to as the Malta fever. During episodes of Malta fever, melitococcemia (presence of brucellae in blood) can typically be demonstrated by means of blood culture in tryptose medium or Albini medium. If left untreated, the disease can give origin to focalizations or become chronic. The focalizations of brucellosis happen usually in bones and joints and spondylodisciitis of lumbar spine accompanied by sacroiliitis is very characteristic of this disease.

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