A severe equine herpesvirus type 1 (EHV-1) abortion outbreak caused by a neuropathogenic strain at a breeding farm in northern Germany

• Published in: Veterinary microbiology Vol. 172; no. 3-4; pp. 555 - 562
• Main Authors: Damiani, Armando Mario, de Vries, Maren, Reimers, Gitta, Winkler, Sonja, Osterrieder, Nikolaus
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 27-08-2014
• Subjects: Abortion; Abortion, Veterinary - epidemiology; Abortion, Veterinary - virology; Animals; Disease Outbreaks - veterinary; EHV-1; Female; Germany - epidemiology; Herpesviridae Infections - epidemiology; Herpesviridae Infections - veterinary; Herpesviridae Infections - virology; Herpesvirus 1, Equid - classification; Herpesvirus 1, Equid - genetics; Horse Diseases - epidemiology; Horse Diseases - virology; Horses; Neurological marker; Outbreak; Pregnancy; Germany; EHV-1; Outbreak; Abortion; Neurological marker
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2014.06.023

A particularly severe equine herpesvirus type 1 (EHV-1) abortion outbreak occurred at a breeding farm in northern Germany. Sixteen of 25 pregnant mares that had received regular vaccination using an inactivated vaccine aborted and two gave birth to weak non-viable foals in a span of three months, with 89% of cases occurring within 40 days after the initial abortion case. Virological examinations revealed the presence of EHV-1 in all cases of abortion and serological follow-up in mares confirmed recent infection. Molecular studies identified a neuropathogenic variant (Pol/ORF30 A2254 to G2254) that belonged to geographical group 4 of EHV-1 isolates. The abortion outbreak was preceded by a case of mild ataxia of unknown cause in a mare that aborted four months after the ataxic episode. Although vaccination of pregnant mares did not prevent abortion, good EHV-1 immune status of the population at the time of outbreak may have had an impact in the failure of manifestation of the neurological form of the disease.