Demodicosis is a relatively common parasitic skin disease in dogs that results when the normally harmless Demodex spp. mites in hair follicles multiply to excessive numbers. Clinical presentation can vary, but severe lesions and secondary infection are possible.
Demodicosis is often classified as juvenile-onset or adult-onset. This new VetCompassTM study is the largest ever study of the disease using anonymised data from primary-care clinics in the UK and revealed breed effects as a major risk factor for disease in both age groups. There are differing spectra of predisposed breeds across the juvenile-onset and adult-onset forms, with dominance of bull type breeds in juvenile-onset demodicosis. Knowledge of the predisposed breeds for these two presentations can assist with diagnosis and support the concept of distinct causal phenotypes.
Key findings from the study of 788 demodicosis cases from 455,553 dogs attending VetCompass™ participating practices during 2013 included:
- Overall demodicosis prevalence was 0.17%.
- Juvenile-onset (<2 years) demodicosis (0.48%) was more common than adult-onset (> 4 years) demodicosis (0.05%).
- Seven breeds showed increased risk of juvenile-onset demodicosis: British bulldog, Staffordshire bull terrier, Chinese shar-pei, dogue de Bordeaux, pug, French bulldog and boxer.
- Six breeds showed reduced risk of juvenile-onset demodicosis: Lhasa apso, bichon frise, Labrador retriever, German shepherd dog, shih-tzu and Chihuahua.
- Six breeds showed increased risk of adult-onset demodicosis: Chinese shar-pei, shih-tzu, West Highland white terrier, boxer and Border terrier.
Full study is freely available open access: O'NEILL, D. G., TURGOOSE, E., CHURCH, D. B., BRODBELT, D. C. & HENDRICKS, A. 2019. Juvenile-onset and adult-onset demodicosis in dogs in the UK: prevalence and breed associations. Journal of Small Animal Practice https://onlinelibrary.wiley.com/ doi/epdf/10.1111/jsap.13067