5-94
ID: Brucellosis
COL Naomi Aronson, MC, USAIntroduction: Brucellosis is a common febrile illness in the Mideast, Mexico and South America. It is a
bacterial infection acquired by ingesting raw milk, unpasteurized cheese or by direct contact with secretions
or birth products of infected animals (cattle, goats, buffalo, camels, reindeer, caribou, yaks, coyotes, deer or
swine). Average incubation period is 2 weeks, but can take up to several months.
Subjective: Symptoms
Acute (1-7days): PM fever > 100°F; profuse, malodorous sweating; flu-like symptoms and a peculiar taste
in mouth Sub-acute (1-2 weeks): Fever, weight loss, arthralgias and myalgias Chronic (weeks to months):
Recurrent undulant fever if not treated, arthralgias or arthritis, constipation, depression and back pain.
Focused History: Exposure– Have you had any raw milk or cheese? Have you come in contact with cattle,
goats, buffalo, camels, reindeer, caribou, yaks, coyotes, deer or swine? Fever– Do you have a fever? (up
to 104°F). How long have you had fever? (weeks to months). Pain– Do any of your joints hurt? (arthritis is
usually in the knee or hip). Do you have back pain? (particularly unilateral sacro-iliac symptoms).
Objective: Signs
Inspection: Temperatures to 104°F
Palpation: Acute (1-7 days): Generalized adenopathy Sub-acute (1-2 weeks): Hepatomegaly (>50%),
splenomegaly (30%)
Assessment: Travel history, animal exposure and consuming unpasteurized milk products.
Differential Diagnosis: Enteric fever, nonpulmonary tuberculosis, or non-falciparum malaria (with chronic
relapses of fever), may have similar symptoms.
Plan:
Treatment
Primary: Doxycycline 100mg po bid x 6 weeks with gentamicin 5mg/kg q 24 hours IV x 14 days (danger
of renal insufficiency)
Alternate: Doxycycline 100 mg po bid and rifampin 900 mg qd, but twice as high relapse rate
Patient Education
Diet: Avoid untreated milk; boil milk if pasteurization status is unknown.
Medications: Avoid doxycycline in children <7. Trimethoprim-sulfamethoxazole and rifampin can be used
as an alternate regimen but 30% relapse rate.
Prevention and Hygiene: Handle animal carcasses carefully. Hunters should use gloves or barriers when
dressing wild animals. Be careful when handling tissues and fetuses from aborted animals.
No Improvement/Deterioration: Return for persistent fever over 7 days.
Follow-up Actions
Consultation Criteria: Refer chronically febrile patients to higher level of care when available.
Zoonotic Disease Considerations
Agent: Brucella canis, B. suis, B. abortus, B. melitensis
Principal Animal Hosts: Dogs (B. canis), swine (B. suis), cattle (B. abortus), goats (B. melitensis)
Clinical Disease in Animals: Dogs (B. canis) - Last trimester abortions; swine (B. suis) - abortion; cattle (B.
abortus) - last half gestation abortions; goats (B. melitensis) - abortion.
Probable Mode of Transmission: B. abortus - Contact with birth products and consumption of milk products,
B. melitensis - Consumption of milk products
Known Distribution: B. canis - rare, B. suis - northern hemisphere, B. abortus & B. melitensis - worldwide