Prevalence of Brachyspira pilosicoli and "Brachyspira canis" in dogs and their association with diarrhoea.

The aims of this study were to investigate the prevalence of colonization with intestinal spirochaetes in dogs, and to assess their association with diarrhoea. To achieve this, faecal samples from 311 dogs were obtained between November 2008 and April 2009 and cultured for Brachyspira species. A total of 41 Brachyspira spp. isolates were recovered, and these were classified into species according to their biochemical properties, and results of a B. pilosicoli species-specific PCR, and partial amplification of the nox gene with sequencing of the product. An overall Brachyspira spp. prevalence of 13.2% (41/311) was obtained. The prevalence of Brachyspira pilosicoli faecal shedding was 4.8% (15/311) while "Brachyspira canis" was identified in 8.0% (25/311) of the sampled dogs. One dog shed an isolate tentatively identified as B. intermedia. A statistically significant association between the shedding of B. pilosicoli and the presence of diarrhoea in dogs was demonstrated (P<0.001). Risk factors for shedding of Brachyspira spp. were investigated. Using the odds ratio, the risk of B. pilosicoli shedding was five times higher among dogs up to 1 year of age as compared with adult dogs (older than 1 year). These findings may have practical implications in the public and animal health fields.