Epidemiological Aspects of Equid Herpesvirus-Associated Myeloencephalopathy (EHM) Outbreaks

Authors

Eva Klouth, Ludwig-Maximilians University
Yury Zablotski, Ludwig-Maximilians University
Jessica L. Petersen, University of Nebraska-Lincoln
Marco de Bruijin, Wolvega Equine Hospital
Gittan Gröndahl, National Veterinary Institute (SVE)
Susanne Müller, Baden-Wuerttemberg Animal Health Services
Lutz S. Goehring, University of Kentucky

Date of this Version

11-21-2022

Citation

Klouth, E.; Zablotski, Y.; Petersen, J.L.; de Bruijn, M.; Gröndahl, G.; Müller, S.; Goehring, L.S. Epidemiological Aspects of Equid Herpesvirus-Associated Myeloencephalopathy (EHM) Outbreaks. Viruses 2022, 14, 2576. https://doi.org/10.3390/v14112576

Comments

Open access.

Abstract

: Equid Herpesvirus Myeloencephalopathy (EHM) is a multifactorial disease following an EHV-1 infection in Equidae. We investigated a total of 589 horses on 13 premises in Europe in search of risk factors for the development of EHM. We found that fever (p < 0.001), increasing age (p = 0.032), and female sex (p = 0.042) were risk factors for EHM in a logistic mixed model. Some breeds had a decreased risk to develop EHM compared to others (Shetland and Welsh ponies; p = 0.017; p = 0.031), and fewer EHV-1-vaccinated horses were affected by EHM compared to unvaccinated horses (p = 0.02). Data evaluation was complex due to high variability between outbreaks with regards to construction and environment; viral characteristics and the virus’s transmissibility were affected by operational management. This study confirms earlier suspected host-specific risk factors, and our data support the benefit of high vaccine coverage at high-traffic boarding facilities.