Equine piroplasmosis: assessing the threat to the UK and Ireland

Coultous, Robert Makepeace (2019) Equine piroplasmosis: assessing the threat to the UK and Ireland. PhD thesis, University of Glasgow.

Abstract

Equine piroplasmosis (EP) is a disease of major welfare and economic concern. Despite a near ubiquitous prevalence globally, the UK and Ireland currently enjoy freedom from endemic EP disease. However, equines entering the UK and Ireland are not screened for EP, and populations of ticks capable of transmitting EP have been identified in England and Wales. Consequently, entry and establishment of EP is of great welfare and financial concern to the equine industry. This study, comprised of several aspects, set out to determine the threat of EP to the UK and Ireland.
A survey of laboratory submissions identified an EP seroprevalence of 8 % and 3.5 % in UK and Irish samples respectively. Further screening of these samples with an optimised Babesia/Theileria catch-all 18S SSU rRNA nested PCR detected circulating Theileria equi parasite in a small (<1 %) but significant proportion. A qualitative risk assessment identified the overall risk of introduction and spread of EP into the UK as low, however the consequences of EP establishment were assessed as significant. Recommendations were made to bring UK policy inline with OIE guidelines and those of other EP-free countries.
Theileria equi DNA samples identified in the UK submissions demonstrated an expected high degree of genetic diversity, with representatives from three of five previously described clades. To aid a more rapid method of genotyping T. equi, a new qPCR subtyping technique was developed and trialled on an EP positive Gambian sample population. The technique was successful in identifying multiple genotype infections both within and between individuals.
Irish T. equi samples appeared homogeneous at the 18S SSU rRNA locus, potentially suggesting iatrogenic transmission. For greater genetic resolution, a novel microsatellite panel was developed and demonstrated a genetic diversity within the samples that was inconsistent with clonal spread.
The results of this study provide data for further advances in diagnostic specificity and sensitivity for detection of EP, and recommends government policy change to maintain national herd biosecurity.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Due to copyright restrictions the full text of this thesis cannot be made available online. Access to the printed version is available.
• Keywords: Theileria equi, Babesia caballi, equine, piroplasmosis, UK, Ireland.
• Subjects: S Agriculture > SF Animal culture > SF600 Veterinary Medicine
• Colleges/Schools: College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine; College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Funder's Name: Horserace Betting Levy Board (HBLB)
• Supervisor's Name: Weir, Dr. William
• Date of Award: 2019
• Depositing User: Dr Robert Coultous
• Unique ID: glathesis:2019-74336
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 20 Aug 2019 16:17
• Last Modified: 21 Aug 2019 08:16
• Thesis DOI: 10.5525/gla.thesis.74336
• URI: https://theses.gla.ac.uk/id/eprint/74336