Brucellosis is a disease spread from animals to humans and is caused by bacteria known as Brucella. Infected goats, hogs and cattle (the bacteria resides in these animals) are involved in spreading the infection to humans. It is a common disease among the resident of countries such in Latin and Central America as well around the Mediterranean. People in other countries such as United States where this infection is not prevalent acquire this disease due to ingestion of imported meat and cheese products which are infected.
Symptoms may appear suddenly and include fever, chills (feeling cold) and sweating or they may appear over a gradual period of time with symptoms such as weight loss, fever, chills, sweating, weakness and exhaustion after performing even light activity. Headaches, pain in the abdomen and back with weight loss, constipation and joint pains can also occur.
Chronic cases may result due to untreated or improperly treated cases. Symptoms may persist for years with episodes of normal body temperature between attacks. Organs such as liver (hepatomegaly) and spleen (splenomegaly) may be enlarged. There may be swellings in the axilla or neck due to enlargement of the lymph nodes (lymphadenopathy)
If brucellosis is not properly managed then long term complications may arise. These complications involve the major organs of the body and symptoms related to these organs may later appear.
- Endocarditis (inflammation of the heart due to the infection)
- Meningitis (inflammation of the brain covering)
- Arthritis (inflammation of the joints)
- Osteomyelitis (inflammation of the bone due to infection)
- Spondylitis (inflammation of the spine)
Other complications include pneumonia (inflammation of lungs), hepatitis (liver inflammation) and cholecystitis (gallbladder inflammation) although these are less common.
There are three main species of Brucella bacteria – Brucella abortus, Brucella suis and Brucella melitensis which are responsible for infections in humans. Transmission of the infection to humans occurs by contact with infected meat, people working in slaughter houses or contact with placentae of infected animals during calving. It can also occur due to ingestion of the infected unpasteurized milk or cheese. After the first contact with the infected animal source, the disease may become evident only after a few days to several weeks. Although any person can be infected, it is more likely to occur in a person in very close contact with animal tissue and there the added risk of a prolonged and severe infection in patients with a weak immune system.
Diagnosis is made by taking blood, urine and CSF (fluid from brain) samples and checking for presence of the bacteria. It is important to excluded disease such as flu, glandular fever and enteric fever as these diseases have similar symptoms.
Infection is treated with antibiotics. To prevent complications and totally eradicate the infection, a combination of two antibiotics are prescribed and longer courses of therapy may be required. An antibiotic such as doxycycline is given in combination with rifampicin for as long as 6 weeks. Alternatively, antibiotics such as streptomycin or gentamicin injected intramuscularly daily for 7 days can be tried as therapy with these agents have the lowest rate of recurrence.