OCTOBER 2024 VOLUME 33, NO.4
A PUBLICATION BY THE UNIVERSITY OF KENTUCKY DEPARTMENT OF VETERINARY SCIENCE, MAXWELL H. GLUCK EQUINE RESEARCH CENTER FUNDED BY:
EQUUS / STANDARDBRED STATION, INC. M&J INSURANCE
IN THIS ISSUE KENTUCKY, 2-3 Application of shotgun metagenomics for diagnosing infectious causes in clinical cases NATIONAL, 4 A look at poor performance in horses INTERNATIONAL, 5-6 Third Quarter 2024 International report on equine infectious diseases Climate change impacts on Central Kentucky horse pastures
T H A N K YO U SPONSORS
R E S E A R C H S P OT L I G H T All hands on deck to conquer herpesviruses – the Goehring Research Laboratory Equid alphaherpesvirus 1 (EHV-1), formerly known as equine herpesvirus 1, is an important viral infection in horses with global prevalence. EHV-1 causes considerable economic losses for the equine industry while also resulting in a significant emotional hardship to horse owners when their horses become infected. The virus primarily spreads through the respiratory route, initially replicating in the upper respiratory tract. In some horses, it spreads further into the bloodstream, causing viremia, which can lead to complications such as abortions, neonatal death and Equine Herpesvirusassociated Myeloencephalopathy (EHM). While all of these outcomes are significant, EHM typically garners the most attention when it causes sudden (mild, moderate or severe) spinal cord disease. Transmission of EHV-1 from horse to horse occurs through direct contact, particularly via nose-to-nose contact, and indirectly through airspace or contaminated objects, such as gear and buckets, in addition to the sometimesforgotten hands that go from horse to horse. Like most, if not all, herpesviruses, EHV-1 can enter a latent or dormant state after an acute infection. EHV-1 latency can persist for years, and, potentially, for life in the trigeminal ganglion and the lymphatic system. Upon reactivation, this virus returns to the respiratory tract where it may result in new rounds of infection transmission. Understanding EHV-1 latent infection and what circumstances trigger reactivation from latency is one important area of study in the laboratory at the University of Kentucky Department of Veterinary Science’s Gluck Equine Research Center.
consistency with regards to the detection of EHV-1 in the lymph nodes of the upper respiratory tract for the youngest horse with tissue samples positive for EHV1 DNA at 14 months old. It was also found that there was no linear increase of viral DNA presence with aging despite the fact that it is always assumed there is continuous EHV-1 exposure. These findings add to the complexity of ‘going dormant’ and ‘reawakening’ of herpesviruses and need further attention.
Leading the work in this area is Edward Olajide, DVM from Nigeria and PhD student in the lab of Lutz Goehring, DVM, PhD. Early results from Olajide’s research show that, as predicted, EHV-1 DNA most commonly found in the trigeminal ganglion of horses. Interestingly, EHV-1 DNA is also found in the mesenteric lymph node (lymph nodes in the abdomen), which was not anticipated. Further, there was not
In collaboration with other laboratories, the lab also focuses on evaluating both current and newly developed vaccines and therapeutics, conducting immunogenicity studies and performing clinical trials to ensure the efficacy and safety of these vaccines. With collaborators at Kansas State University and Michigan State University, the lab is evaluating novel RNA vaccines similar to the potent Covid-19 vaccines
Photo Courtesy Dr. Edward Olajide.
OCTOBER 2024 | 1