Human Brucella canis Infection by Contact with an Asymptomatic Infected Dog

WALLACH J; DEODATO B; BENCHETRIT G; MARÍA EUGENIA CORTINA; UGALDE JE; CIOCCHINI A. E.; COMERCI D. J

Berlín

Conferencia; Brucellosis 2014 International Research Conference Including the 67th Annual Brucellosis Research Meeting; 2014

Brucellosis International Research Association

Brucella canis, the main etiologic agent of canine brucellosis, can be transmitted to humans by either laboratory accidents or close contact with infected dogs, principally after an abortion. Human Brucella canis infection is frequently mild or asymptomatic. In symptomatic cases, clinical signs are variable and typically present as an acute febrile illness with flu-like symptoms. Complications are infrequent and include arthritis, spondylitis and epididymo-orchitis. Neurologic signs (including meningitis, uveitis and optic neuritis), anemia, internal abscesses, nephritis, endocarditis and dermatitis can also occur and other organs and tissues can be affected, resulting in a wide variety of syndromes. Even though antibiotic treatment is effective, relapses can occur. In untreated individuals, mortality rates vary from less than 2% to 5% being endocarditis and meningitis the most frequent causes of death.Case report: A 37-year-old previously healthy male sought medical care in a general hospital due to fever, myalgia and headache that had begun 3 days earlier. No pathological signs were found by physical examination and laboratory studies showed moderate elevation of transaminases and alkaline phosphatase. At that moment, two samples for blood culture were taken and symptomatic treatment was indicated. The patient attended to control again 48 hours later with worsening symptoms, hepatomegaly demonstrated by ultrasonography, and increased levels of transaminases. Since the blood cultures were positive for a Gram-negative bacilli, hospitalization was decided and antibiotic treatment (ciprofloxacin 400 mg IV every 12 hours and ampicillin/sulbactama 1.5 g IV every 6 hours) indicated. Few days later, the isolated bacteria was identified as Brucella spp. and the treatment was switched to streptomycin at 1 g/d IM and doxycycline 100 mg b.i.d. orally. After treatment, the patient experienced clinical remission with normal transaminase values and negative results in subsequent blood cultures. After discharge, the patient was referred to the Hospital of Infectious Diseases FJ Muñiz for follow-up. Laboratory typing tests identified the blood culture isolated bacterium as Brucella canis. In addition, serum samples obtained during hospitalization were tested for antibodies against smooth Brucella strains (RBT, STA, STA-2ME, CFT and cELISA) and rough strains (RSAT and iELISA for B. canis). Positive results were obtained with RSAT and iELISA for B. canis, whereas the remaining tests were negative. The clinical examination and a questionnaire indicated that the patient was asymptomatic except for a mild intermittent diarrhea. Additionally, he referred living with a healthy male dog who had presented positive blood cultures for B. canis. For this reason, we decided to carry out serological tests on the patient?s family including his wife and their three children. His wife was asymptomatic and exhibited positive results by RSAT and iELISA, whereas the children were negative. This case demonstrates the transmission of canine brucellosis to pet owners from an apparently healthy dog with a B. canis-positive blood culture. This type of transmission, not commonly seen in immunocompetent individuals, highlights the need for greater controls of canine brucellosis in pet dogs.