Wright - Markey Prof of Equine Infectious Diseases Martin-Gatton College of Agriculture, Food and Environment, University of Kentucky LEXINGTON, Kentucky, United States
Abstract: Background - Equid alphaherpesvirus 1 (EHV-1) is a respiratory tract pathogen of horses and can cause herd outbreaks of (equine herpesvirus) myeloencephalopathy (EHM) or abortions. EHM outbreaks have occurred at equestrian events, and there is a need for surveillance at shows. Air space sampling during Covid-19 has shown efficacy as a surveillance tool. Hypothesis – Air sampling at equestrian events will detect ‘air-borne’ EHV-1 genome copies. Animals –There was no direct contact with horses. Methods - Observational study: an air sampler (Bertin™ Coriolis, France) was placed in stable units with (minimum of) 5 occupied stalls out of 10. On each event day we collected an air volume of 18m3 between 10pm - 4am. By 9am we collected surface samples from each occupied stall. All samples were tested for EHV-1, EHV-2 and EHV-4 using quantitative PCR and specific primers and probes. We report presence or absence in (surfaces-S) or (air-A) samples, as well as low ( < 1000), or medium ( < 10,000) abundance of target genome copies. Results – Ranked detection frequencies for EHV-2, EHV-1 and EHV-4 were: 5 events, A16/S40; 5 events, A16/S24, and 2 events, A13/ S12. Abundance was overall ‘low’ for air or surfaces samples. At 2 events we detected ‘medium’ EHV-1 or EHV-4 abundance in air, which corresponded with ‘medium’ abundance on select surfaces. EHV-1 detection was restricted to winter events. There were no reported clinical cases during any event. Conclusions and Clinical Importance – we provide evidence for regular, low-abundance presence of EHV1 &4 genome copies at equestrian events.
