title: Detection of Equine Herpesvirus (EHV) -1, -2, -4 and -5 in Ethiopian Equids with and without Respiratory Problems and Genetic Characterization of EHV-2 and EHV-5 Strains.
abstract: Infections with equine herpesviruses (EHVs) are widespread in equine populations worldwide. Whereas both EHV-1 and EHV-4 produce well-documented respiratory syndromes in equids, the contribution of EHV-2 and EHV-5 to disease of the respiratory tract is still enigmatic. This study describes the detection and genetic characterization of EHVs from equids with and without clinical respiratory disease. Virus-specific PCRs were used to detect EHV-1, -2, -4 and -5. From the total of 160 equids with respiratory disease, EHV-5 was detected at the highest prevalence (23.1%), followed by EHV-2 (20.0%), EHV-4 (8.1%) and EHV-1 (7.5%). Concurrent infections with EHV-2 and EHV-5 were recorded from nine (5.2%) diseased horses. Of the total of 111 clinically healthy equids, EHV-1 and EHV-4 were never detected whereas EHV-2 and EHV-5 were found in 8 (7.2%) and 18 (16.2%) horses, respectively. A significantly higher proportion of EHV-2-infected equids was observed in the respiratory disease group (32/160, 20.0%; P = 0.005) compared to those without disease (8/111; 7.2%). EHV-2-positive equids were three times more likely to display clinical signs of respiratory disease than EHV-2-negative equids (OR 3.22, 95% CI: 1.42-7.28). For EHV-5, the observed difference was not statistically significant (P = 0.166). The phylogenetic analysis of the gB gene revealed that the Ethiopian EHV-2 and EHV-5 strains had a remarkable genetic diversity, with a nucleotide sequence identity among each other that ranged from 94.0 to 99.4% and 95.1 to 100%, respectively. Moreover, the nucleotide sequence identity of EHV-2 and EHV-5 with isolates from other countries acquired from GenBank ranged from 92.9 to 99.1% and 95.1 to 99.5%, respectively. Our results suggest that besides EHV-1 and EHV-4, EHV-2 is likely to be an important contributor either to induce or predispose equids to respiratory disease. However, more work is needed to better understand the contribution of EHV-2 in the establishment of respiratory disease.
authors.affiliation: Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.|College of Veterinary Medicine and Agriculture, Addis Ababa University, Debre Ziet, Ethiopia.
authors.forename: H
authors.identifier: http://orcid.org/0000-0001-9313-5462
authors.initials: H
authors.lastname: Negussie
authors.affiliation: National Animal Health Diagnostic and Investigation Center, Sebeta, Ethiopia.
authors.forename: D
authors.initials: D
authors.lastname: Gizaw
authors.affiliation: National Veterinary Institute, Debre zeit, Ethiopia.
authors.forename: L
authors.initials: L
authors.lastname: Tesfaw
authors.affiliation: Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Veterinary Medicine, Nihon University, Fujisawa, Kanagawa, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Oguma
authors.affiliation: School of Veterinary Medicine, Nihon University, Fujisawa, Kanagawa, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Sentsui
authors.affiliation: Institute of Biotechnology, College of Natural and Computational Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
authors.forename: T S
authors.initials: TS
authors.lastname: Tessema
authors.affiliation: Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: H J
authors.initials: HJ
authors.lastname: Nauwynck
mesh_terms: D000818:Animals; D018397:Equidae; D005002:Ethiopia / Q000453:epidemiology; D005260:Female; D018142:Gammaherpesvirinae / Q000235:genetics*; D006566:Herpesviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D006734:Horse Diseases / Q000453:epidemiology* / Q000821:virology; D006736:Horses; D008297:Male; D010802:Phylogeny; D015995:Prevalence; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D018144:Rhadinovirus / Q000235:genetics* / Q000302:isolation & purification; D018140:Varicellovirus / Q000302:isolation & purification*
keywords: Ethiopia; donkeys and horses; equine herpesviruses; respiratory disease