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Low virulent respiratory viruses in standardbred trotters

relationship to health and athletic performance

Back, Helena (2015). Low virulent respiratory viruses in standardbred trotters. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2015:95
ISBN 978-91-576-8388-5
eISBN 978-91-576-8389-2
[Doctoral thesis]

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Respiratory viral infections are known to affect equine health worldwide and are commonly associated with clinical signs such as fever, cough, and nasal discharge. While clinical respiratory signs will prevent horses from training and racing, it is also known that horses can be infected by viruses and yet not exhibit any clinical signs (i.e. subclinically infected). However, it is not clear whether these subclinical infections may have any effect on the horse´s performance and health.
In this thesis well-known equine respiratory viruses such as equine influenza (EIV) and herpesvirus (EHV) type 1 and 4, as well as the less explored equine rhinitis A and B virus (ERAV and ERBV) and EHV type 2 and 5, were investigated on monthly basis in a longitudinal study over a year in actively racing Standardbred trotters. The presence and amount of the viruses and their antibodies were identified by diagnostic methods such as serology and PCR assays. Genetic information was obtained by sequencing. The health of the horses was also monitored and their performance determined by both objective and subjective methods.
A high seroprevalence of ERAV and ERBV in the samples suggested that these viruses were widespread in the study cohort of well-managed horses. EHV-5 and EHV-2 were detected in about three-quarters and almost one third of the nasal secretions samples respectively. We could however not find any associations between these subclinical infections and poor performance.
This work also includes a case report of equine multinodular pulmonary fibrosis (EMPF) in a horse, which was identified with co-infection by EHV-5 and the asinine herpesvirus type 5.
Genetic analysis of a segment of the gB gene of EHV-5 in healthy horses with two samples taken one year apart and from the EMPF case study horse pre and post mortem allowed to classify EHV-5 strains into four different genotypes. While viral strains appeared stable over time, horses could be infected with multiple strains that varied in detection qualitatively and quantitatively over time. The single strain detected in the EMPF case was also found in the clinically normal horses.

The work in this thesis provides knowledge of subclinical presence of respiratory viruses in elite Standardbred trotters and further genetic information of EHV-5 showed a range of interactions between EHV-5, the host and the environment over time.

Authors/Creators:Back, Helena
Title:Low virulent respiratory viruses in standardbred trotters
Subtitle:relationship to health and athletic performance
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2015
Depositing date:September 2015
Number of Pages:79
IBack, Helena; Kendall, Anna; Grandón, Rodrigo; Ullman, Karin; Treiberg Berndtsson, Louise; Ståhl, Karl and Pringle, John(2012). Equine Multinodular Pulmonary Fibrosis in association with asinine herpesvirus type 5 and equine herpesvirus type 5: a case report. Acta Veterinaria Scandinavica 54:57.
IIBack, Helena; Penell, Johanna; Pringle, John; Isaksson, Mats; Ronéus, Nils; Treiberg Berndtsson, Louise and Ståhl, Karl (2015). A longitudinal study of poor performance and subclinical respiratory viral activity in Standardbred trotters. Veterinary Record Open 2:e000107.
IIIBack, Helena; Ullman, Karin; Treiberg Berndtsson, Louise; Penell, Johanna; Ståhl, Karl; Valarcher,Jean-François and Pringle, John(2015). Viral load in nasal secretion of equine herpesviruses 2 and 5 in actively racing Standardbred trotters: temporal relationship of shedding to clinical findings and poor performance. Veterinary Microbiology 179(3-4), 142-148.
IVBack, Helena*; Ullman, Karin*; Leijon, Mikael; Söderlund, Robert; Penell, Johanna; Ståhl, Karl; Pringle, John and Valarcher, Jean-François (2015). Genetic variation and dynamics of infections of equine herpesvirus type 5 (EHV-5) in individual horses (Submitted manuscript). *Shared first authorship
Place of Publication:Uppsala
Publisher:Department of Clinical Sciences, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-8388-5
ISBN for electronic version:978-91-576-8389-2
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:L Animal production > L50 Animal physiology and biochemistry
L Animal production > L73 Animal diseases
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 403 Veterinary Science > Clinical Science
Agrovoc terms:racehorses, respiratory diseases, viruses, equine influenzavirus, equine herpesvirus, rhinitis, animal performance, body condition, health, laboratory diagnosis, antibodies, pcr
Keywords:ERAV, ERBV, EHV-2, EHV-5, EMPF, equine, poor performance, viral load, phylogenetic analysis
Permanent URL:
ID Code:12569
Faculty:VH - Faculty of Veterinary Medicine and Animal Science
Department:(VH) > Dept. of Clinical Sciences
External funders:Stiftelsen Hästforskning
Deposited By: Helena Back
Deposited On:03 Sep 2015 13:50
Metadata Last Modified:10 Sep 2020 13:41

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