Synopsis
Distinguish two livestock-associated zoonoses, protect laboratory staff, identify focal infection and pregnancy risk, and use organism-specific testing, combination treatment and public-health escalation.
- Brucellosis follows unpasteurised dairy, livestock birthing products, abattoir or laboratory exposure, or contact with infected imported dogs, particularly Brucella canis.
- Brucellosis commonly causes prolonged or undulating fever, drenching sweats, fatigue, weight loss, arthralgia and hepatosplenomegaly; bone, neurological and cardiac foci must be sought.
- Before blood cultures, warn the laboratory that Brucella is suspected; request reference serology and PCR with species-specific exposure details.
- Standard smooth-Brucella serology may not detect Brucella canis reliably, so explicitly identify dog exposure and request B. canis testing.
- Uncomplicated adult brucellosis is commonly treated with doxycycline 100 mg twice daily plus rifampicin 600 to 900 mg once daily for six weeks under specialist care.
- Q fever follows inhalation of Coxiella burnetii-contaminated aerosols, especially from sheep, goats, cattle, placenta, birth fluids, wool, dust or manure.
- Acute Q fever causes abrupt fever, severe headache, atypical pneumonia or hepatitis; many infections are asymptomatic.
- Persistent focal Q fever most often affects abnormal or prosthetic valves and aneurysmal or grafted vessels; pregnancy is another high-risk setting.
- First-line acute Q fever treatment in a suitable non-pregnant adult is doxycycline 100 mg twice daily for 14 days.
- Brucellosis is clinician-notifiable in England; Brucella species and Coxiella burnetii are laboratory-notifiable organisms, and clusters or occupational hazards need health-protection input.
Key red flags
A new murmur, heart failure, embolic signs or persistently raised inflammatory markers suggests Brucella endocarditis or persistent focal Q fever.
Severe headache, meningism, cranial neuropathy, confusion, myelopathy or focal weakness may be neurobrucellosis or Q fever neurological disease.
Back pain, focal bony tenderness, painful hip or sacroiliac joint can indicate Brucella spondylodiscitis or osteoarticular infection.
Known vascular aneurysm, prosthetic graft or valvular disease increases the risk and consequence of persistent focal Q fever.
Pregnancy with either infection requires urgent obstetric and infection input because fetal loss, preterm birth and placental infection can occur.
Tell the microbiology laboratory before handling cultures from suspected brucellosis because aerosol-generating work can infect laboratory staff.
Sacroiliitis, spondylodiscitis, peripheral arthritis, epididymo-orchitis, hepatosplenic lesions, neuroinfection and endocarditis explain localising symptoms or relapse.
Months of fever, fatigue, weight loss, valve dysfunction, vascular pain or emboli can follow apparently mild or unrecognised acute infection.
Investigation priorities
Separate Brucella from Q fever and identify persistent-infection risk before selecting tests.
Management branches
Prolonged fever follows unpasteurised dairy, livestock, abattoir, laboratory or infected-dog exposure.
- Record species, product, country, dates and occupational contacts, then examine joints, spine, liver, spleen, testes, nervous system and heart.
- Telephone microbiology before culture processing, obtain multiple blood cultures and send reference serology and PCR as advised.
- Request B. canis-specific assessment when dog breeding, imported dogs, reproductive tissue or a known canine case is relevant because routine serology may miss it.
- Image localising symptoms and obtain echocardiography when fever is prolonged, cultures persist or cardiac features are present.