EHV-1 outbreak in Valencia (ESP)
06.03.2021 - Recommendations by European College of EquineInternal Medicine
ECEIM guidelines for dealing with returning horses from EHV-1 outbreaks
In light of the current outbreak of Equine Herpes Virus-1 (EHV-1) the European College of EquineInternal Medicine (ECEIM) has decided to provide the following guidelines available to anyone dealing withhorses returning from Valencia/Spain or as general guidelines to deal with such outbreaks. Horseowners should seek advice from their veterinarian but may wish to quote these guidelines.
EHV-1 is a common virus that affects horses worldwide and can cause mild respiratory disease, andon occasion, serious complications of neurological gait deficitsClinical signs may include nasaldischarge, cough, a rectal temperature greater than 38.3°C/101.5°F, enlarged submandibular lymphnodes and oedema of the limbs and/or ventral abdomen. Neurological signs can be any of urinary/faecal incontinence, penile prolapse, weak tail, being unsteady on its feet or even beingunable to stand, which may deteriorate requiring euthanasia. Owners of horses suffering from anyon these signs or in contact with a horse with any of these signs please contact your veterinarianimmediately.
All horses returning home from Valencia/Spain or from a show where horses from Valencia werepresent should undergo the following protocol:
- Undergo appropriate quarantine
(separated from other horses and ponies by distance,airspace or building, and supported by separate personnel and equipment).
- Strict hygiene rules apply for contact with horses (hand hygiene, protective clothing or achange of clothes including shoes, use of separate equipment).
- Home-coming horses should be tested upon arrival (Day 1 nasal swab PCR) and isolated inquarantine. If arrival swabs are all negative, and no clinical signs (see point 5) were noticed it issafe to lift quarantine after 28 days.
- To shorten quarantine time all isolated horses should be tested again on day 14. A nasal swabis collected and submitted for PCR testing for EHV-1 to an accredited laboratory on that day,and a second swab should be submitted immediately when the day 14 swab returns with anegative test result (this strategy increases the test sensitivity to above 80%). If all tests arenegative (including day 1), and there were/are no clinical signs consistent with EHV-1 infection,horses can return to the main group.
- Alternatively, paired samples for serology (antibody titer) obtained 14 days apart may also aid todetect recent exposure to virus but will not replace nasal swab testing.
- If horses travel together when returning to their home facility and do not show any abnormalclinical signs (point 5), they can all be isolated together. Any horse positive on a nasal swab fromday 1 or showing clinical signs (see point 5) should be individually quarantined and tested. Ifthe group is tested by day 14 or any later time point and one sample is positive, the entiregroup needs to stay in quarantine until further notice and testing.
- Monitor for respiratory signs such as nasal discharge, cough, submandibular lymph nodeenlargement/sensitivity, and monitor for signs of limb/ventral oedema. Take rectaltemperatures twice daily and report temperatures >38.3°C. Any of these abnormal signs shouldprompt EDTA-venous blood testing for EHV-1 viraemia (EHV-1 PCR testing via an accreditedlaboratory). Any positive PCR result during the quarantine period will postpone the release fromquarantine.
- When dealing with a group of quarantined horses, a positive test result of an individual horseshould prompt separation from the group and individual isolation.
- Exercising quarantined horses: light work, if possible outdoors, and not together with any ofthe horses that are not in quarantine. If this is not possible, the quarantined horses should beexercised after the remainder of the herd (e.g. at the end of day).
- Adjust feeding to the level of exercise.
- If a horse is already on NSAIDs for management of other conditions fever might be masked so if possible NSAIDs should not be used while the horse’s temperature is being monitored.
- Vaccination: It is not recommended to vaccinate horses in quarantine. Tetanus vaccinationin case of emergency is allowed. Healthy EHV-vaccinated horses, with no fever, that were/arenot in contact with the quarantined yard, can receive an EHV booster (not earlier than 4-6weeks from first dose), but maximum immunity will be reached approx. 10 days later. Horseswithout EHV vaccination history will have maximum immunity 10 days after the secondvaccination (booster), so it will take usually 6 weeks from the rst dose to gain immunity.Considering the risk of quarantine breech on premises that host an isolated group, we do notrecommend starting EHV vaccination on these premises. Horses on neighboring farms (fenceline, distance, no exchange between farms) can start rst dose or booster of their healthyanimals. Keep in mind, some rst-time vaccinates respond with swelling at injection site and/ora fever for 1 – 2 days. In general, horses that received a vaccine injection should be rested for 1– 2 days, then on a light exercise schedule for the remainder of the week.
For further advice please check www.eceim.info/diplomats tond a Recognised Equine Internal Medicine Specialist closest to you: https://www.eceim.info/diplomats.
Lutz Göhring, Karsten Feige, Marianne Sloet, Dominique De Clercq, Vinzenz Gerber, OrsolyaKorbacska-Kutasi, Marco Duz, Jessika-M. Cavalleri, Anne Couroucé
25 July 2021, 11:00 (CEST)