Molecular Detection and Genetic Characteristics of Equine Herpesviruses 1 and 4 in Egypt.
Abstract: The present study investigated the molecular detection and genetic characteristics of equine herpesvirus 1 (EHV-1) and EHV-4 circulating within Egyptian horse populations during 2019-2022. A total of 79 animals were sampled (54 nasal swabs and 25 aborted fetal tissues). PCR assays revealed that 24 (30.3%) and 7 (8.8%) samples were positive for EHV-1 and EHV-4, respectively. Additionally, 5 (6.3%) samples were concurrently infected with both viruses. Four EHV-1 and three EHV-4 isolates were genetically characterized based on partial sequencing of gB gene. The four EHV-1 strains displayed 100% nucleotide identity to one another and to EHV-1 reference strains reported in Egypt and other countries. The three EHV-4 strains were phylogenetically classified into two distinct clusters based on their nucleotide sequences (76%-100% identity). Meanwhile, their deduced amino acid sequences differed by only one amino acid substitution. Our results underscore the critical importance of EHV-1 and EHV-4 as primary contributors of abortion and respiratory illness in horses and highlight the need for further large-scale surveillance and in-depth characterization studies to improve our understanding of these viruses' epidemiology in Egypt and to develop a robust control strategy.
Copyright © 2025 Emad AL-Ebshahy et al. Veterinary Medicine International published by John Wiley & Sons Ltd.
Publication Date: 2025-10-10 PubMed ID: 41112826PubMed Central: PMC12534148DOI: 10.1155/vmi/9719058Google Scholar: Lookup
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Summary
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Molecular testing identified two types of equine herpesviruses (EHV-1 and EHV-4) in Egyptian horses, with genetic analysis showing close relationships among virus strains. The study emphasizes the viruses’ role in equine diseases and the need for further research and control measures.
Study Purpose and Background
- The study aimed to detect and analyze the genetic characteristics of equine herpesvirus types 1 and 4 (EHV-1 and EHV-4) circulating among horses in Egypt.
- Equine herpesviruses are significant pathogens that cause respiratory disease and abortion in horses, impacting horse health and potentially causing economic losses.
- Understanding the genetic makeup of these viruses can inform epidemiology, control strategies, and vaccine development.
Sample Collection and Testing
- A total of 79 samples were collected between 2019 and 2022 from horses in Egypt, including:
- 54 nasal swabs from living horses exhibiting symptoms
- 25 aborted fetal tissues
- Polymerase Chain Reaction (PCR) assays were used to detect the presence of EHV-1 and EHV-4 DNA in the samples.
Key Findings on Virus Detection
- 24 out of 79 samples (30.3%) tested positive for EHV-1.
- 7 out of 79 samples (8.8%) tested positive for EHV-4.
- 5 samples (6.3%) were found to be concurrently infected with both EHV-1 and EHV-4.
- The detection of EHV-1 was notably higher than EHV-4 in this population and period.
Genetic Characterization of Virus Isolates
- Partial sequencing was performed on the glycoprotein B (gB) gene from:
- Four EHV-1 isolates
- Three EHV-4 isolates
- For EHV-1 isolates:
- All four strains showed 100% nucleotide sequence identity with one another.
- They matched closely with known EHV-1 strains previously reported in Egypt and internationally, indicating genetic stability.
- For EHV-4 isolates:
- The three strains clustered into two genetically distinct groups, with 76%-100% nucleotide similarity between them.
- The deduced amino acid sequences of these strains differed by only one amino acid substitution, suggesting minor protein-level variation.
Implications and Recommendations
- The detection of both EHV-1 and EHV-4 confirms their active circulation and etiological role in causing abortion and respiratory illness in Egyptian horses.
- The genetic similarity of EHV-1 strains implies potential endemic stability or repeated circulation of common strains in Egypt.
- The genetic diversity observed among EHV-4 strains suggests multiple viral lineages circulating concurrently.
- The study highlights the importance of ongoing, larger-scale surveillance and detailed genetic studies to better understand virus epidemiology.
- Such information is critical for devising effective control and prevention strategies, including vaccination and management practices, to reduce disease burden in horses.
Cite This Article
APA
Al-Ebshahy E, Badr Y, El-Ansary RE, Alajmi R, El-Ashram S, Rady A, Elgendy E.
(2025).
Molecular Detection and Genetic Characteristics of Equine Herpesviruses 1 and 4 in Egypt.
Vet Med Int, 2025, 9719058.
https://doi.org/10.1155/vmi/9719058 Publication
Researcher Affiliations
- Department of Microbiology, Faculty of Veterinary Medicine, Alexandria University, Abees 10th, Alexandria 21944, Egypt.
- Department of Infectious Diseases and Epidemics, Faculty of Veterinary Medicine, Damanhour University, Damanhour, El Beheira 22511, Egypt.
- Zoology and Entomology Department, Faculty of Science, Al-Azhar University, Cairo, Egypt.
- Zoology Department, Faculty of Science, King Saud University, Riyadh 11451, Saudi Arabia.
- Zoology Department, Faculty of Science, Kafrelsheikh University, Kafr El-Sheikh 33516, Egypt.
- College of Life Science and Engineering, Foshan University, 18 Jiangwan Street, Foshan 528231, Guangdong Province, China.
- Department of Microbiology, Faculty of Veterinary Medicine, Alexandria University, Abees 10th, Alexandria 21944, Egypt.
- Department of Virology, Faculty of Veterinary Medicine, Damanhour University, Damanhour 22511, Egypt.
- Department of Microbiology and Immunology, Wake Forest University School of Medicine, Biotech Place, Winston-Salem 27101, North Carolina, USA.
Conflict of Interest Statement
The authors declare no conflicts of interest.
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