TitleViral testing of 10 cases of Theiler's disease and 37 in-contact horses in the absence of equine biologic product administration: A prospective study (2014-2018).
Publication TypeJournal Article
Year of Publication2019
AuthorsTomlinson, JE, Tennant, BC, Struzyna, A, Mrad, D, Browne, N, Whelchel, D, Johnson, PJ, Jamieson, C, Löhr, CV, Bildfell, R, McKenzie, EC, Laverack, M, Renshaw, RW, Dubovi, E, Kapoor, A, Meirs, RS, Belgrave, R, Engiles, J, Van de Walle, GR, Divers, TJ
JournalJ Vet Intern Med
Date Published2019 Jan
KeywordsAnimals, Biological Products, Female, Hepatitis, Viral, Animal, Horse Diseases, Horses, Liver, Male, Parvoviridae Infections, Parvovirus, Prospective Studies, Real-Time Polymerase Chain Reaction

BACKGROUND: A novel equine parvovirus (EqPV-H) was recently discovered in the equine liver with Theiler's disease.

OBJECTIVES: To determine the prevalence of EqPV-H infection in naturally occurring Theiler's disease cases and in-contact horses in the absence of historical equine biologic product administration.

ANIMALS: Ten cases of Theiler's disease from 6 separate properties were included in the study, based on the criteria of acute onset of clinical signs of liver failure with laboratory or histopathologic findings characteristic of Theiler's disease and no history of receiving an equine biologic product within the preceding 4 months. In addition, 37 in-contact horses from 4 of the 6 properties were screened for EqPV-H infection and hepatitis.

METHODS: In prospective case series, cases were diagnosed with Theiler's disease by the attending veterinarian and were tested for EqPV-H by PCR of liver or serum. In-contact horses were assessed via serum chemistry and PCR at the attending veterinarian's discretion. Hepatitis was defined as serum gamma-glutamyltransferase activity above reference interval. The association of EqPV-H with hepatitis was determined by Fisher's exact test.

RESULTS: Nine of 10 (90%) Theiler's disease cases and 54% of tested in-contact horses were EqPV-H positive. Hepatitis was significantly associated with EqPV-H infection (P = .036).

CONCLUSIONS AND CLINICAL IMPORTANCE: Although further study is required to identify EqPV-H as the causative agent of Theiler's disease, EqPV-H appears strongly associated with cases of fatal Theiler's disease and subclinical hepatitis in horses in contact with those cases. The prevalence of EqPV-H infection on affected properties can be high.

Alternate JournalJ Vet Intern Med
PubMed ID30520132
PubMed Central IDPMC6335540
Grant List2016 Advancement in Equine Research Award / / Boehringer Ingelheim /
/ / Harry M. Zweig Memorial Fund for Equine Research /
2016-67015-24765 / / National Institute of Food and Agriculture /
/ / Niarchos Family /