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Brucellosis is a contagious disease of both humans and animals caused by bacteria (invisible to the naked eye) of the genus Brucella which causes extensive economic damage to cattle breeding but is also a significant health issue as more than 50.000 people contract brucellosis world-wide.
Among animals, brucellosis is transmitted directly (contact with placenta, aborted fetus, the liquor , vaginal and/or uterus secretion) or indirectly (if infected and non-infected health herds mix while grazing or by contact with environment in which the bacteria can be found such as manure, pastures, water, etc). Most infected male animals continue to secrete Brucella via semen for the lifetime. Presence of infectious agents in udder and surrounding lymph nodes results in permanent or occasional secretion of Brucella via milk and as such it is a serious source of infection for young animals which can also be infected via uterus. In infected lambs and young goats, Brucella inhabits lymph nods of bowls and can be secreted out of their body via droppings. Infected young cattle develop the disease once they reached sexual maturity. Sheppard dogs can also spread brucellosis between ruminants but they can also get ill as well. In high humidly, low temperature and unsunny weather conditions, Brucella can survive for up to few months in water, aborted material, manure, wool, hay, on equipment or clothes. In organic materials (dirt, soil) Brucella is resistant to drying as well. Most common sources of disease in humans are contact with aborted material of infected animal via mucus, conjuctiva and damaged skin, as well as via food of undercooked dairy and meet products. Laboratory staff, butchers and people working in wool business usually get infected by breading in the infectious agent found in tissue and wool. There are reports of doctors of veterinary medicine getting infected in incidents involving blood sampling or treatment of live Brucella vaccines (syringe stabs). Transmission of brucellosis from human to human is very rare plus it can also be sexually transmitted, transmitted by bone marrow transplant, blood transfusion and from breastfeeding mother to her nursing child.
It takes anything from five days to three moths (usually its two weeks) from infection to the first symptoms of the disease. Brucellosis strikes suddenly and is accompanied by symptoms that resemble to common cold such as fever, headache, joint pain, muscle pain, fatigue, etc. Profuse sweating typically occurs in the night, as does chough and sometimes even chest pain. Reported gastric problems include loss of appetite, nausea, vomiting, alternating diarrhea and constipation, especially in adults. In many patents, symptoms last from 2 to 4 weeks followed by spontaneous recovery. Other patients develop intermitting fever and other symptoms which fade and intensify in intervals ranging from 2 to 14 days. In patients whit such ‘undulent’ fever, recovery lasts between 3 to 12 months. Clinical sighs can reoccur (relapse) months after the initial stage of infection, even after a successful treatment. Most common complications of brucellosis include joint inflammation and spine, testis, liver, and skin conditions, as well as long-lasting fatigue. Cases of nervous system being affected by brucellosis are characterized, inter alia, by brain envelope inflammation and meningitis and are reported in 5% of the patients. However, most severe complication of brucellosis is endocarditis (heart valves inflammation) with possible fatal outcome. Symptoms of brucellosis in pregnant women can include premature birth or birth of underweight infants with respiratory problems and jaundice. Human brucellosis can be prevented by control of infection in animals. Heat processing (cooking) of food products of animal origin, good hygiene and use of protective clothes and equipment are essential in prevention of brucellosis, in particular in high-risk professions (farmers, veterinaries, butchers, laboratory staff). Long-term antibiotics therapy reports good results. However, patients suffering from endocarditis must undergo surgery.
Duration of the period between infection and first symptoms in animals depends on how far along was pregnancy at the time of infection. Thus such period is longer if the animal contracted the disease early on in its pregnancy. Miscarriage and premature birth in goats and sheep normally occur 2 weeks to 2 months after the infection, in cows five month after it and in bitches miscarriage and early birth occur between 7th and 9th week into the pregnancy. In goat and sheep herds which are exposed to brucellosis for the first time, miscarriage percentage can range from 30% up to high 80%. Aborting animals often get retained placenta. Goats and sheep normally miscarriage once but re-infection of uterus and secretion of the infectious agent can also occur during the subsequent pregnancies which normally come about normal. In both animals that miscarriage and those that did not, significant drop in lactation is reported although clinical signs of udder inflammation are every rare. Male animas can develop acute testicular inflammation which normally leads to infertility. Joint inflammations were reported in both male and female animals. In sheep and goats which are not pregnant, the disease normally develops without any clinically visible symptoms. In beef cattle, symptoms caused by B. melitensis are similar to those in sheep and goats. In dogs, infection caused by B. melitensis often goes about without clinical symptoms. However, cases of miscarriage and testicular inflammation were reported in dogs as well. In dogs, the infectious agent is quickly eliminated from the system.
Each miscarriage in sheep herds should be a brucellosis alarm signal although other diseases such as Q fever can cause similar symptoms. This is why it is necessary to perform laboratory tests and get the right diagnosis. Reliable diagnosis can only be reached through laboratory tests (blood work). In Bosnia and Herzegovina, diagnostic methods are proscribed by the law, more specifically quick agglutination (rose bengal) is used as the orientation method and RVK is the confirmation method. In case of miscarriage, blood samples should be sent immediately after the miscarriage and 2 to 3 weeks afterwards in order to avoid possible false negative results. Serologically positive reactors are considered to be ill animals and they should be treated in accordance with the relevant legislation.
B. melitensis is usually transferred onto healthy animals by infected animal from the herd. This is why any new additions to the herd should be test. Control of brucellosis can be carried out by running tests on animas and removal of positive reactors from the herd. Interestingly enough, infected goats, following miscarriage or a normal birth, continue to secrete the infectious agent via vaginal secretion, whereas in sheep this period is shorter and is typically 2 to 3 weeks in duration. This is why it is necessary to remove any positive reactors from the herd as soon as possible, aborted material should be disposed off and burned and each site exposed to infected animals or contaminated aborted material should be meticulously cleaned and disinfected (most commercially available disinfectants such as solutions of hypochlorite, 70% ethanol, isopropanol, iodoforms, 2% to 3% caustic soda and other similar disinfectants are all efficient against Brucella). Sterilization of kits and equipment (used by veterinaries, physicians) are preformed in dry-heat environment [160-170°C for at least 1 hour]. Solutions can be decontaminated by boiling for 10 minutes. Inactivation of infectious agents in liquid stable dung can be successfully preformed in 2 to 4 weeks using xilen (1ml/liter) and calcium cyanamide (20 kg/m3). In many countries, live attenuated Rev 1 vaccines are used to exercise control of infections caused by B. melitensis.

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