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138.e4 Brucellosis

DIAGNOSIS • For detection of B. canis in whole blood client’s costs, financially and emotionally.
(not serum or plasma), semen, or vaginal Isolate any incoming animals for 8-12 weeks
Diagnostic Overview
VetBooks.ir If exposure to B. canis is suspected from a is highly sensitive (97.14%) and specific Drug Interactions
discharge, polymerase chain reaction (PCR)
and test before introduction into the house
or kennel.
(100%).
reproductive history or subsequent physical
examination, a blood sample is drawn for
of Brucella at the genus level may be
screening test, and protective care is provided ○ Identification and characterization in PCR • Cautious use with combinations of antibiotic
for human or canine contact with the animal. performed using primers targeting highly categories
If preliminary results are positive, isolation and conserved regions such as Bcsp31 or • Check renal function, antimicrobial sensitivi-
further client communication about treatment 16S-rRNA. ties, dosages, and availability
options continue as a precaution until confirma- ○ B. canis outer membrane protein 25 DNA
tion test results for blood, body fluids, or tissue quantitative PCR from vaginal swab and Possible Complications
are received. urine samples provides early detection of Relapse or additional clinical signs as bacteremia
B. canis infection in dogs before detection persists
Differential Diagnosis of antibodies.
• Abortion (p. 2) Recommended Monitoring
• Infertility/poor semen quality/azoospermia: TREATMENT Dogs diagnosed with brucellosis should be
improper timing of breeding, subclinical considered infected for life. Neutered dogs
uterine infection, testicular or prostatic Treatment Overview should be periodically treated with antibiotics
disease Goals of treatment: to decrease risk of bacteremia and subsequent
• Scrotal enlargement: orchitis, epididymitis, • Minimize spread to other animals and shedding. Otherwise, euthanasia is indicated
torsion of spermatic cord, hernia, testicular humans through immediate quarantine, for any dog that has a confirmed positive test
neoplasia, abscess, varicocele, hydrocele, testing, and removal or euthanasia of affected result.
hematoma dog(s).
• Stop progression of systemic disease in affected PROGNOSIS & OUTCOME
Initial Database animals by surgical neuter, extended antimi-
• Screen blood sample with card or rapid slide crobial use, semi-isolation, and retesting. • Poor prognosis, guarded at best
agglutination test (p. 1319) with 2-mercap- • Dogs remain affected for life because of the
toethanol (RSAT with 2-ME [D-Tec CB]) Acute General Treatment intracellular location of B. canis, ongoing
or submit to diagnostic laboratory for • Euthanasia should be treatment of choice fluctuation of serologic titers, and ineffective
overnight result (immunofluorescent assay in most cases. bactericidal treatment.
[IFA], tube agglutination test [TAT]). • Alternatively, ovariohysterectomy/castra- • No infected dog should be used for breeding,
○ Positive 8-12 weeks after infection tion decreases the potential reservoirs of even if treated with antibiotics.
○ Negative results are 95% accurate unless organisms. Emphasis should be given to
dog exposed < 2 months; then retest. B. recurrence of symptoms and discouraging PEARLS & CONSIDERATIONS
canis has rough surface antigen and does exposure of affected dogs to children,
not cross-react with B. abortus antigen immunocompromised individuals, and Comments
(smooth Brucella spp) when basing pregnant women. • Dogs with a negative screening test (RSAT
diagnosis on serum tube agglutination. • Antibiotic therapy is lengthy, expensive, and or TAT) result, especially those that show
○ False-positives are common (50%-60%). requires consistent owner compliance. no overt clinical signs, are considered not
Any positive result should be sent for a Failures or relapses occur. No regimen is 100% infected with B. canis unless tested within
confirmation test (agar gel immunodif- effective. Animals can never be considered 12 weeks after exposure.
fusion [AGID]). cleared of the organism. Combination of • Blood samples from any dog testing
multiple drugs is better than any single positive from a preliminary test should be
Advanced or Confirmatory Testing antibiotic. immediately checked by AGID. A dog with
• AGID test uses cytoplasmic antigens, is very ○ Tetracycline 30 mg/kg PO q 12h or a negative AGID result is considered not
specific, and identifies a positive dog 8-12 doxycycline 10 mg/kg PO q 12h for 1 infected.
weeks after infection until 3-4 years after month in combination with gentamicin • Infected animals should not be housed with
achieving abacteremia. 5 mg/kg SQ q 24h × 7 days, repeated persons susceptible to infection.
• Aerobic bacterial culture of blood is defini- every 3 weeks. • Even neutered dogs may be infected; testing
tive. Sterilely collected tissue aspirates (e.g., ○ Rifampin 5.5 mg/kg PO q 24h has been should be considered in cases of discospon-
lymph node, vertebral disc material) and added in some cases. dylitis or uveitis if an alternative cause is not
urine from cystocentesis can also be ○ Enrofloxacin alone 5 mg/kg PO q 24h identified.
cultured. Semen, vaginal secretions, and for 4 weeks has been reported in limited
tissue/urine samples not sterilely collected use. Prevention
are contaminated with other organ- • Intermittent serologic testing months after • All intact male and female dogs should be
isms, prohibiting reliable culture of B. cessation of antibiotic(s). screened for B. canis if accidentally bred by
canis. Positive cultures occur 2-4 weeks a stray or feral dog, exposed to aborted tissue
after infection (i.e., weeks earlier than Chronic Treatment or body fluids, and before breeding or semen
titers). • Periodic antibiotic therapy as described shipment.
○ False-negatives are possible depending on previously may be beneficial in decreasing • Quarantine required by certain state regula-
the phase of bacteremia and previous titers but not in eliminating the disease or tory agencies for facility if a positive test
antibiotic therapy. One negative culture its potential relapse. result occurs; enforced for minimum of 2
does not rule out disease. • Quarantine kennel or facility: no animals months until negative results reported
○ Higher sensitivity with multiple samples in or out. Test all animals, including older
from disease-related tissue (lymph node, pups. Repeat test monthly until 3 consecutive Technician Tips
bone marrow, placenta, eye, fetus) or fluid months of negative results. Remove or • Obtain a thorough reproductive history from
(semen, lochia, urine, milk) euthanize all positive dogs. Be aware of owners of intact dogs.

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