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Disease Alerts

Updates on current disease outbreaks are listed here as they occur and will include the date listed, disease name, location and current status. Specific premises will not be named but the general location by town, county and state will be listed. When locations, events or horses are at risk they will be listed. Updates will be posted as they are received.



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Anne Arundel, MD
Outbreak Identifier: 4606
Alert ID: 2010
March 30, 2021
Confirmed Case(s) - Official Quarantine

Maryland State Veterinarian

Number Confirmed: 36;
Facility Type: Racetrack;
Notes: Update 3/30/2021 Alert ID# 1976 and 1999: On March 22, 2021 three horses in a large barn at Laurel Park racetrack developed fevers and were tested. Also, a horse at Pimlico racetrack developed a fever and was tested. One of the horses in the large barn at Laurel Park tested positive for EHV while the rest were negative. The positive horse was sent to the Bowie racetrack which is now the quarantine facility. The positive test result triggered a reset of the quarantine timeline for Laurel Park. On March 24,2021 the testing of the entire large barn was commenced. Approximately 120 asymptomatic horses were tested. In addition, the second round of testing on the index barn at Laurel was also conducted involving 14 asymptomatic horses. The first round of testing for the index barn consisting of 20 asymptomatic horses resulted in 6 positive horses for EHV. These horses were removed and sent to Bowie. The results for the index barn retest was one horse was positive. The positive horse was moved to Bowie. The result from testing of the large barn was 26 positive horses. These horses were moved to Bowie. A horse with the fever at Pimlico was tested and found negative. The retest result of the horse from Pimlico was positive for EHV. This horse was also moved to Bowie. Another 2 horses developed fevers from a different barn at Laurel Park and these horses were tested. One tested positive and was sent to Bowie. As of Sunday March 28, 2021, there are 36 positive horses at Bowie. After analyzing the results from the multi- barn and multi- horse testing, the decision was made to have separate quarantines for the three properties. It was necessary to have the separation so that events at one property would not affect the others. The decision was also made to stop further testing asymptomatic horses because the testing was not resolving the problem. Only symptomatic horses will be tested as defined by EHM recommendations for State Animal Health Officials. All three properties are placed on a 21-day quarantine. The properties will be out of quarantine as followed: Pimlico will be release April 12, 2021, Bowie April 17, 2021, and Laurel April 18, 2021. This schedule is contingent that no horse with clinical signs tests positive on the initial testing during the 21-day period. MDA is working closely with racetrack officials to monitor the situation and adjust plans accordingly. For more information go to:  EHM factsheet