Detection of Equid Alphaherpesvirus 1 from Arabian Horses with different clinical presentations between 2016-2019 in Egypt.
Authors: Ahdy Ahmed M, Ahmed Basem M, Elgamal Mahmoud A, Shaalan Mohamed, Farag Ibrahim M, Mahfouz Eman R, Darwish Hassan R, Sayed-Ahmed Mohamed Z, Shalaby Mohamed A, El-Sanousi Ahmed A
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: EHV-1 Detection in Arabian Horses across Egypt (2016–2019) Equid alphaherpesvirus 1 remains a significant threat to equine health, particularly in the Middle East, where it causes upper respiratory disease, abortion, and neurological complications with substantial mortality rates. Researchers investigating outbreaks in Cairo and Giza governorates sampled 66 Arabian horses presenting with respiratory, abortigenic, or neurological signs over four years, using both immunohistochemistry and real-time PCR (targeting glycoprotein B and ORF33 genes) to confirm EHV-1 infection. Of 25 confirmed cases, the majority presented with reproductive disease (14 abortions, 3 stillbirths, and 2 neonatal deaths), whilst 5 horses showed respiratory signs and 1 displayed neurological involvement; molecular analysis revealed the detected strains clustered closely with European EHV-1 variants, suggesting possible epidemiological links. These findings underscore the critical importance of rapid, accurate diagnosis through PCR-based methods rather than relying on clinical presentation alone, and they provide compelling justification for strategic vaccination of pregnant mares in endemic regions. Given the virus's propensity for reproductive losses in Arabian populations, practitioners should implement strict biosecurity protocols during outbreaks, consider serological screening in breeding stock, and discuss prophylactic vaccination strategies with owners—particularly those operating in high-risk areas where EHV-1 circulation appears established.
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Practical Takeaways
- •EHV-1 vaccination of pregnant mares should be prioritized as a preventive measure, given the high prevalence of abortigenic complications (76% of positive cases) in Arabian horses in Egypt
- •Implement rapid molecular diagnostics (real-time PCR) for suspected EHV-1 cases to enable quick quarantine and control measures, reducing spread across breeding populations
- •Maintain awareness that EHV-1 presents with variable clinical manifestations (respiratory, reproductive, neurological) requiring a broad diagnostic index of suspicion across multiple disease presentations
Key Findings
- •EHV-1 was detected in 25 of 66 Arabian horses (37.9%), predominantly in abortigenic cases (19 of 25 cases) compared to respiratory (5 cases) and neurological (1 case) presentations
- •Abortigenic outcomes included 14 abortions, 3 stillbirths, and 2 early neonatal deaths, demonstrating EHV-1's significant impact on reproductive health
- •Molecular characterization revealed ORF33 sequences were closely related to European EHV-1 strains with no amino acid sequence differences from previously published Egyptian EHV-1 sequences
- •Immunohistochemistry and real-time PCR targeting gB and ORF33 genes provided reliable diagnostic detection methods for field-based EHV-1 diagnosis