Brucella canis is a rarely diagnosed bacterium that causes brucellosis in domestic and wild dogs and is considered an emerging threat worldwide. People and animals can be infected through contact with an infected dog's body fluids and aborted material.
- In dogs: usually infertility and miscarriage, though some show no signs.
- In people: vague symptoms such as fever, joint pain and fatigue — but illness can be debilitating, with endocarditis, an enlarged spleen or neurologic symptoms.
- Infections are probably underreported: symptoms are nonspecific, the organism is hard to detect, and tests vary widely. No serologic test is approved for diagnosing people.
What happened
| Date (2023) | Event |
|---|---|
| August 14 | A stray dog wandered onto the property of a family of four (two children and a dog), who fostered her for two weeks |
| August 28 | A family of five — with an infant, a toddler, two dogs and two ferrets — adopted her |
| September 18 | Taken to a veterinarian for vaginal discharge; found to be pregnant |
| September 23 | She miscarried seven puppies; the vet sent a B. canis screening test (indirect fluorescent antibody, IFA) |
| September 27 | Screening test positive; the vet notified the state health department |
| October 2 | The state lab confirmed infection by culture and PCR; given the poor prognosis and the risk to people, the dog was euthanized |
Tracing exposures
Local epidemiologists interviewed both families and the clinic. In all, 17 people and five animals had been exposed: the foster family and their dog, the adoptive family and their two dogs and two ferrets, and eight veterinary clinic staff.
- High risk: three members of the adoptive family had handled aborted material and puppies without protective equipment. They received post-exposure antibiotics — three weeks of doxycycline and rifampin, adapted from existing brucellosis protocols — and were monitored for 24 weeks.
- Lower risk: everyone else — collecting specimens with protective gear, feeding, petting or walking the dog, or (for the ferrets) casual household contact — was told to watch for symptoms.
- The adoptive family's two dogs tested negative, but the family declined the recommended 8-week follow-up tests.
At 24 weeks, no one reported symptoms in themselves or their pets.
Lessons
A team of veterinarians, pet owners, epidemiologists, public health veterinarians, physicians and lab scientists confirmed the diagnosis, found the exposures and guided treatment. With no human blood test available, symptom monitoring plus preventive antibiotics for high-risk exposures was the approach.
- Veterinarians should consider B. canis in any dog with miscarriage or infertility, and test to confirm; molecular or rapid agglutination tests can help limit spread and guide treatment for exposed people.
- Be more suspicious with stray dogs and dogs from breeding kennels, where brucellosis is more common.
- There is no vaccine for dogs or people, so protective equipment is critical for staff handling dogs giving birth or miscarrying.
- Communicating the risk to owners and staff is essential, and veterinarians should know their state's reporting requirements for brucellosis.
Sources
Based on Moore TS, Lancaster A, Nelson J, et al., "Notes from the Field: Multidisciplinary Approach to Investigating Brucella canis Exposures — South Carolina, September 2023," Morbidity and Mortality Weekly Report, Centers for Disease Control and Prevention; a work of the United States government in the public domain.
Licence: CC0 1.0 (public domain) · Adapted from www.cdc.gov
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