Evidence for unapparent Brucella canis infections among adults with occupational exposure to dogs.

Human serological assays designed to detect brucellosis will miss infections caused by Brucella canis, and low levels of periodic bacteremia limit diagnosis by blood culture. Recent B. canis outbreaks in dogs and concomitant illnesses in caretakers suggest that unapparent human infections may be occurring. With more than a quarter of a million persons in occupations involving dogs, and nearly 80 million dog owners in the United States, this pathogen is an under-recognized human health threat. To investigate occupational exposure to B. canis, we adapted a commercial canine serological assay and present the first controlled seroepidemiological study of human B. canis infections in recent years. 306 adults with occupational exposure to dogs and 101 non-matched, non-canine-exposed subjects were enrolled. Antibodies were detected using the canine D-Tec(®) CB rapid slide agglutination test (RSAT) kit with a secondary 2-mercaptoethanol (ME)-RSAT. Results were validated on a blinded subset of sera with an additional RSAT and indirect enzyme-linked immunoassay at the National Administration of Laboratories and Health Institutes (ANLIS) in Argentina. Seroprevalence ranged from 10.8% (RSAT) to 3.6% (ME-RSAT) among canine-exposed subjects. Kennel employees were more likely to test RSAT seropositive compared with other canine exposures (OR = 2.7; 95% CI, 1.3-5.8); however, low seroprevalence limited meaningful occupational risk factor analyses. Two seropositive participants reported experiencing symptoms consistent with brucellosis and having exposure to B. canis-infected dogs; however, temporality of symptom onset with reported exposure could not be determined. D-Tec(®) CB results had substantial agreement with ANLIS assays (Cohen's kappa = 0.60-0.68). These data add to a growing body of literature suggesting that people occupationally exposed to dogs may be at risk of unapparent B. canis infection. It seems prudent to consider B. canis as an occupational public health concern and encourage the development of serological assays to detect human B. canis infections.

No serologic evidence for zoonotic canine respiratory coronavirus infections among immunocompetent adults.

Zoonotic diseases continue to emerge and threaten both human and animal health. Overcrowded shelters and breeding kennels create the perfect environment for amplified infectious disease transmission among dogs and present a critical opportunity for zoonotic pathogens to emerge and infect people who work in close contact with dogs. Coronaviruses' widespread prevalence, extensive host range, various disease manifestations and increased frequency of recombination events all underline their potential for interspecies transmission (Methods Mol. Biol. 2008, 454, 43). The objectives of this study were to determine whether people with occupational contact with dogs were more likely to have antibodies against canine respiratory coronavirus (CRCoV) compared to persons with no dog exposure. A seroepidemiological cohort study was completed, for which 302 canine-exposed and 99 non-canine-exposed study subjects enrolled in the study by providing a serum sample and completing a self-administered questionnaire. A competitive enzyme-linked immunosorbent assay (ELISA) was developed to detect human antibodies against CRCoV while controlling for cross-reacting antibodies against the human coronavirus OC43. All study subjects were negative for antibodies against CRCoV by this competitive ELISA. This study supports the premise that humans are not at risk for CRCoV infections; however, infrequent cross-species transmission of CRCoV cannot be ruled out.