Prevalence factors associated with equine herpesvirus type 1 infection in equids with upper respiratory tract infection and/or acute onset of neurological signs from 2008 to 2014

Abstract

The objective of the present case-control study was to determine prevalence factors associated with the detection of equine herpesvirus type 1 (EHV-1) by quantitative PCR (qPCR) in horses presented to veterinarians with clinical signs related to an upper respiratory tract infection and/or acute onset of neurological disease from March 2008 to December 2014. Nasal secretions and whole blood from 4228 equids with acute onset of fever, respiratory signs and/or neurological deficits were tested by qPCR for EHV-1. Categorical analyses were performed to determine the association between observations and EHV-1. A total of 117/4228 (2.7 per cent) equids tested qPCR-positive for EHV-1, with most of the isolates belonging to the non-neuropathogenic genotype (N752). EHV-1 PCR-positive equids were over-represented in racing horses. Depression, anorexia, nasal discharge and coughing were significantly less frequently reported in the EHV-1 qPCR-positive equids compared with the EHV-1 qPCR-negative cases. Neurological deficits were more frequently reported in the EHV-1 qPCR-positive cases. This study provides contemporary information on the frequency of EHV-1 detection by qPCR in blood and nasal secretions from horses with fever, respiratory signs and neurological deficits.

Equine Asthma: Current Understanding and Future Directions

“…Young performance horses, such as racing horses, have an increased risk of respiratory viral infections. This relates to age susceptibility, commingling, stress and suboptimal biosecurity protocols (119,122,123).…”

How common is equine herpesvirus type 1 infection?

“…Specific topics that should be of interest to the equine industry include identifying the triggers that reactivate the virus in the respiratory tract (as well as at other sites) and factors that control the level and duration of nasal shedding. The data presented by Pusterla and others (2015) contribute to this long-term goal.…”

“…The apparent recent increase in the numbers of reported cases of equine herpesvirus myeloencephalopathy (EHM) in the USA and Europe (Kydd and others 2012) have caused concerns among veterinarians regarding possible transmission of EHV‐1 among hospitalised horses, with the subsequent risk of nosocomial EHM cases. One of the key questions central to such concerns is ‘how common is it for hospitalised horses to shed EHV‐1?’ According to the results of a paper by Pusterla and others (2015) summarised on page 70 of this issue of Veterinary Record , only 2.7 per cent of 4228 horses from 139 veterinary practices throughout the USA tested positive for EHV‐1 DNA in their nasal secretions or blood. The strength of the study includes availability of a large data set from a wide geographical area, with sampling spanning a five‐year period.…”

Report of the Fourth International Havemeyer Workshop on Equid Herpesviruses (EHV) EHV‐1, EHV‐2 and EHV‐5

“…In the USA, of 7632 clinical cases (fever, plus respiratory or acute neurological disease), 2.3% were quantitative PCR positive for EHV-1 in nasal swabs [4]. In Argentina, 7% of abortions, stillbirths or neonatal foal deaths were associated with EHV-1 over a 20-year period (n = 1760) and 97% of these were the non-neuropathogenic (A 2254 ) biovariant.…”