Introduction
Brucellosis is a bacterial infectious disease transmitted to humans by infected animals. Direct transmission from person to person is rare. The disease occurs particularly frequently in the Mediterranean region (especially Turkey), as well as in Africa, Asia, Central and South America and on the Arabian Peninsula.
In Germany, brucellosis is rather rare and is usually the result of imported diseases from abroad. Brucellosis is a worldwide spread bacterial disease caused by various bacteria of the genus Brucella. Brucella are small, immobile, gram-negative cocci, which mainly affect farm animals such as cattle, sheep and goats and which can be transmitted to humans through contact with infected animals.
Important human pathogens, i.e. also infecting humans, are Brucella melitensis (cause of Malta fever and mainly found in goats, sheep and camels), Brucella abortus (mainly in cattle, trigger of Bangs disease), Brucella suis (mainly in pigs) and to a lesser extent Brucella canis (mainly found in dogs). Since the symptoms of brucellosis are often non-specific and variable, early diagnosis is often difficult. A careful anamnesis (medical admission interview) with information on eating habits, occupation and possible stays abroad therefore play an important role, especially in the case of brucellosis. In about 90 percent of cases, brucellosis does not cause any symptoms, in the remaining 10 percent the symptoms vary from slight fever and headaches to severe joint infestation and organ damage. Consequences such as inflammation of the pancreas, liver inflammation, disturbances of the blood count or inflammation of the peritoneum (peritonitis) and heart valves are possible and can sometimes be fatal.
Causes of brucellosis
The most common causes of brucellosis are the consumption of contaminated raw (i.e. uncooked/pasteurised) milk or the consumption of contaminated raw milk products, such as goat’s or sheep’s cheese or raw meat. Especially travellers in the Mediterranean region should take precautions and avoid the consumption of raw milk products and raw meat. Often many of the farm animals living there are infested with brucellosis pathogens.
Transmission is also possible through small injuries to the skin on contact with infected animal products such as urine, faeces and blood. Butchers and veterinarians are particularly at risk and are considered to be professionally exposed risk groups alongside laboratory staff. If the brucellosis pathogens finally enter the human body via mucous membranes or skin injuries, they are usually collected by cells of the immune system and transported to the nearest lymph nodes, where the first place of defence takes place.
If the body does not succeed in fighting the pathogens, brucellosis spreads unhindered into the bloodstream, from where it can attack the nearest organs such as the liver and spleen. Especially in chronic cases, the joints and bone marrow are often affected. The centres of inflammation that develop there often sustain the infection for many years.
