Campylobacter jejuni (C. jejuni) is the most common cause of clinical campylobacteriosis in people. In Denmark, the incidence of human campylobacteriosis is constant, despite a significant reduction in food-borne cases over the last couple of years, indicating a role for other sources of infection.

The aims of the study were as follows: 1) to examine the prevalence of C. jejuni in family dogs younger than 2 years of age in Copenhagen, Denmark; 2) to identify risk factors associated with carriage of C. jejuni; and 3) to examine the association between carriage of C. jejuni and clinical signs of diarrhea. A cross-sectional study in dogs younger than 2 years presenting to the University Hospital for Companion Animals, University of Copenhagen, Denmark, was carried out from May to November 2016. Samples were collected by rectal swabs and stored in a charcoal medium at 4°C for a maximum of 32 hours before culturing. Positive samples were verified using phase-contrast microscopy and whole genome sequencing. All dog owners completed a questionnaire regarding the management of their dogs. Data was analyzed using chi-squared tests and multivariate analyses in SPSS Statistics 24; p<0.05 was considered significant.

Two hundred twenty-four dogs were included. The prevalence of C. jejuni was 9.4% (21/224). Primary feeding with "bones and raw food" (BARF, p=0.008) and regular feeding with dried meat (p=0.01) were significant risk factors for Campylobacter carriage. Dogs younger than 1 year of age fed with BARF and/or dried meat were at greater risk of carrying Campylobacter than dogs older than 1 year of age with the same feeding routines. There was no association between a positive C. jejuni status and concurrent diarrhea, swimming in sea or lake water, having been abroad or living with other pets or children in the family.

Dogs can act as reservoirs for C. jejuni, and raw feeding increases the risk. The carriage of C. jejuni in dogs may pose a zoonotic risk to humans.

Disclosures

Disclosures to report
The Department of Veterinary Clinical Sciences, University of Copenhagen, was granted 25000 DKr (3300 Euro) by the Danish Food Administration for performing the study.