Investigation into the risks for gastrointestinal signs in dogs

The identification of environmental influences and interactions on the development of disease are critical to determine the basis of complex genetic based traits. To date, large and rigorous population based epidemiological studies documenting the incidence and prevalence of diseases in dog breeds, or the environmental influences that affect them, have not been performed.

The Dogslife project (www.dogslife.ac.uk) was launched in 2010 to collate a cohort of Labrador Retrievers for the longitudinal study of health and disease. To date there are over 5,800 dogs enrolled in the project, with data collected on over 16,000 illness episodes, and with dogs followed for up to five years of their life. The collection of questionnaire data, digital uploads, and genetic information through biological samples submitted by participating dog owners, provide a unique resource of environmental and genetic information for epidemiological investigation.

Gastrointestinal (GI) signs are by far the most common illnesses reported by owners of pet dogs. Preliminary analysis of the Dogslife cohort has revealed that frequently GI signs do not result in the requirement for a veterinary presentation, yet they remain a significant cause of morbidity to the pet and owner. These are virtually unreported in the scientific literature, because of the over-reliance on veterinary healthcare records for collating information on such phenotypes. Over half of dogs develop vomiting and/or diarrhoea clinical signs in the first year of life, with approximately one third of dogs developing recurrent episodes. Although a number of infectious causes are known to cause GI signs, specific diagnoses are rare and the aetiology of the majority of cases remains unknown. There is an urgent need to identify the environmental and infectious risk factors for these cases, particularly with regard to potentially modifiable risks that could be used to reduce the high prevalence of GI signs.

Longitudinal evaluation of dogs participating in the Dogslife cohort affords the possibility to assess risks predating the development of GI signs, and to repeat risk evaluations through through life. This PhD project will evaluate the database information recorded of dogs and their exposures during the project and provide a doctoral training in quantitative epidemiology, genomics and microbiome analysis. During the 4-year studentship the successful candidate will evaluate existing and prospectively collected environmental, host genetic, microbial and environmental datasets for the infectious and non-infectious risks associated with the development of GI signs in the Dogslife cohort as they age, and the interactions between them. Microbiome (16S) sequencing, high-density SNP genotyping and novel virus screens will be used to ascertain infectious and genetic risks for the development of GI signs. Nested case-control studies will be included for low-frequency phenotypes, and whole genome sequencing may be used to explore the genetic basis of selected disease traits and their interaction with environmental risk factors.