Brucellosis

Disease Description (Causes and Symptoms)

• Definition: Brucellosis is a zoonotic infection transmitted from animals to humans by bacteria of the genus Brucella (B. abortus, B. melitensis, B. suis, B. canis, etc.). In Korea, it mainly occurs through exposure related to cattle, such as direct contact or contact with contaminated blood and abortion products.
• Pathophysiology: Brucella bacteria enter and multiply inside host cells, such as macrophages, and spread throughout the body. Because they can exist intracellularly, the disease is prone to becoming prolonged and recurring.
• Main symptoms: Fever (intermittent fever), chills, weakness and fatigue, loss of appetite, weight loss, muscle and joint pain, headache, localized pain (in the joints, spine, testicles, etc.), and depression or chronic fatigue-like symptoms. It may progress from acute to chronic disease (lasting months to years). Possible complications include osteoarticular involvement (lumbar spondylitis, arthritis), splenomegaly and hepatomegaly, genitourinary involvement (orchitis and epididymitis), and, rarely, endocarditis or central nervous system involvement.

Treatment Methods

• Diagnosis: Definitive diagnosis is made by isolating (culturing) the bacteria from blood or bone marrow. Serologic tests (antibody tests, ELISA, SAT, etc.) and molecular tests (PCR) are supplementary diagnostic methods; in some countries, testing is performed by public health research institutes.
• Basic principles: Because Brucella bacteria are present inside cells, combination therapy with antimicrobial agents that penetrate cells well is recommended for a sufficient duration (generally at least 6 weeks). Treatment with a single drug has a high risk of failure and recurrence.
• Representative standard regimens for adults (selected according to clinical guidelines)
  • Doxycycline 100 mg orally every 12 hours + streptomycin 1 g IM once daily (usually for 2–3 weeks) → take doxycycline for a total of 6 weeks (the doxycycline + streptomycin combination produces excellent results in some serious cases, such as osteoarticular disease)
  • Or doxycycline 100 mg orally every 12 hours + rifampicin 600–900 mg orally once daily, for a total of 6 weeks
• If complications occur (endocarditis, central nervous system involvement, bone infection, etc.): Long-term antibiotic treatment (several months) and surgical treatment (e.g., heart valve replacement, abscess drainage, bone resection, etc.) may be necessary. Endocarditis has a high risk of death and requires active treatment.
• Special groups: Medication selection differs for pregnant women, infants and young children, and patients with allergies, so consultation with a specialist is necessary (e.g., restrictions on doxycycline use).
• Precautions during treatment: Because treatment is prolonged, adherence to the medication regimen is important. Rifampicin can affect liver function and interact with many medications (e.g., reducing the effectiveness of oral contraceptives), so monitoring is necessary. Streptomycin may cause nephrotoxicity and ototoxicity, so kidney function and hearing should be monitored. Doxycycline may cause photosensitivity.
• Lifestyle management: Get sufficient rest, maintain hydration, and use symptomatic treatment for pain and fever. If occupational exposure is suspected, work restrictions and isolation measures should be considered.

Checklist Before an Outpatient Visit (Including Example Questions)

• Items/documents to prepare
  • A list of medications currently being taken (including prescriptions, OTC medications, and supplements)
  • Recent blood test and imaging results (printouts if possible)
  • Notes on when symptoms began and how they have progressed (fever pattern, location and severity of pain, weight changes, etc.)
  • Occupation and history of animal contact (working on a farm, at a slaughterhouse, in veterinary medicine, or in a laboratory, etc.) and whether recently consumed unpasteurized dairy products (raw milk, raw cheese, etc.)
  • Recent overseas travel history and whether there are any close contacts with similar symptoms
• Examples of questions to prepare for the outpatient visit (it is useful to check these yourself before asking the doctor)
  • When did the symptoms begin, and what is the fever pattern?
  • Have you previously taken antibiotics? (If so, the medication name and duration)
  • Have you previously undergone Brucella testing (serology or culture)?

Examples of General Questions to Ask the Doctor

• How long is the expected treatment period for this medication (or these medications)?
• What are the medication’s main side effects, and which tests should be monitored (liver function, kidney function, hearing, etc.)?
• How likely is recurrence, and what additional tests will be needed if it recurs?
• When would it be appropriate to return to work or resume work duties during treatment?
• Is there a risk of transmission to family members or coworkers? Are any measures needed for close contacts?

Examples of Disease-Specific Questions

• I work on a farm (or at a slaughterhouse, in veterinary medicine, or in a laboratory). What preventive measures (testing, isolation, and protective equipment) are needed before returning to work?
• I have testicular pain (or lumbar pain). How likely is this to lead to infertility or chronic joint problems, and what additional tests should I undergo?

(Note: Diagnosis and treatment vary depending on each individual’s condition, so please discuss the appropriate prescription and decisions with your healthcare provider.)