Diagnosis of brucellosis relies on:
Demonstration of the agent: blood cultures in tryptose broth, bone marrow cultures. The growth of brucellae is extremely slow (they can take until 2 months to grow) and the culture poses a risk to laboratory personnel due to high infectivity of brucellae.
Demonstration of antibodies against the agent either with the classic Huddleson, Wright and/or Bengal Rose reactions, either with ELISA or the 2-mercaptoethanol assay for IgM antibodies associated with chronic disease
Histologic evidence of granulomatous hepatitis (hepatic biopsy)
Radiologic alterations in infected vertebrae: the Pedro Pons sign (preferential erosion of antero-superior corner of lumbar vertebrae) and marked osteophytosis are suspicious of brucellic spondylitis.
The disease’s sequelae are highly variable and may include granulomatous hepatitis, arthritis, spondylitis, anaemia, leukopenia, thrombocytopenia, meningitis, uveitis, optic neuritis, endocarditis and various neurological disorders collectively known as neurobrucellosis.
Treatment and prevention
Antibiotics like tetracyclines, rifampicin, and the aminoglycosides streptomycin and gentamicin are effective against Brucella bacteria. However, the use of more than one antibiotic is needed for several weeks, because the bacteria incubate within cells.
The gold standard treatment for adults is daily intramuscular injections of streptomycin 1 g for 14 days and oral doxycycline 100 mg twice daily for 45 days (concurrently). Gentamicin 5 mg/kg by intramuscular injection once daily for seven days is an acceptable substitute when streptomycin is not available or difficult to obtain. Another widely used regimen is doxycycline plus rifampin twice daily for at least six weeks. This regimen has the advantage of oral administration. A triple therapy of doxycycline, with rifampin and cotrimoxazole, has been used successfully to treat neurobrucellosis. Doxycycline is able to cross the blood–brain barrier, but requires the addition of two other drugs to prevent relapse. Ciprofloxacin and cotrimoxazole therapy is associated with an unacceptably high rate of relapse. In brucellic endocarditis, surgery is required for an optimal outcome. Even with optimal antibrucellic therapy, relapses still occur in 5–10 percent of patients with Malta fever.
The main way of preventing brucellosis is by using fastidious hygiene in producing raw milk products, or by pasteurizing all milk that is to be ingested by human beings, either in its unaltered form or as a derivate, such as cheese. Experiments have shown that cotrimoxazol and rifampin are both safe drugs to use in treatment of pregnant women who have brucellosis.
Epidemiology: Control and eradication efforts
United States
Dairy herds in the USA are tested at least once a year with the Brucella Milk Ring Test (BRT). Cows that are confirmed to be infected are often killed. In the United States, veterinarians are required to vaccinate all young stock, thereby further reducing the chance of zoonotic transmission. This vaccination is usually referred to as a “calfhood” vaccination. Most cattle receive a tattoo in their ear serving as proof of their vaccination status. This tattoo also includes the last digit of the year they were born. The first state–federal cooperative efforts towards eradication of brucellosis caused by Brucella abortus in the U.S. began in 1934.
Greater Yellowstone area
Wild bison and elk in the Greater Yellowstone Area (GYA) are the last remaining reservoir of Brucella abortus in the U.S. The recent transmission of brucellosis from elk to cattle in Idaho and Wyoming illustrates how the GYA is the last remaining reservoir in the United States, adversely affecting the livestock industry. Eliminating brucellosis from this area is a challenge, as there are many viewpoints on how to manage diseased wildlife.
Canada
Canada declared their cattle herd brucellosis-free on September 19, 1985. Brucellosis ring testing of milk and cream, as well as testing of slaughter cattle, ended April 1, 1999. Monitoring continues through auction market testing, standard disease reporting mechanisms, and testing of cattle being qualified for export to countries other than the USA.
Europe
Republic of Ireland
Ireland was declared free of brucellosis on 1 July 2009. The disease had troubled the country’s farmers and veterinarians for several decades. The Irish government submitted an application to the European Commission, which verified that Ireland had been liberated. Brendan Smith, Ireland’s Minister for Agriculture, Fisheries and Food, said the elimination of brucellosis was “a landmark in the history of disease eradication in Ireland”. Ireland’s Department of Agriculture, Fisheries and Food intends to reduce its brucellosis eradication programme now that eradication has been confirmed.
Oceania
Australia
Australia is at present free of cattle brucelosis, although it occurred in the past. Brucellosis of sheep or goats has never been reported. Brucellosis of pigs does occur. Feral pigs are the typical source of human infections.
New Zealand
Brucellosis in New Zealand is limited to sheep (Brucella ovis). The country is free of all other species of Brucella.
