title: Genetic characterization of equine herpesvirus 1 isolates from abortion outbreaks in India.
abstract: Equine herpesvirus 1 (EHV1) is a common pathogen of horses that causes upper respiratory tract disease, abortion, neonatal death and neurological disease. The neurological form of disease is called equine herpesvirus myeloencephalopathy (EHM). During the past decade, the incidence of EHM has been on the rise in Europe, North America, Australia and Asia. Some EHV1 isolates causing EHM exhibit a single-nucleotide polymorphism (SNP) in the DNA polymerase gene (ORF30) at position 2254 (A2254to G2254). Further, based on polymorphism in the ORF68, EHV1 isolates have been classified into different groups. The aim of the present study was to estimate the genetic diversity of EHV1 and to determine the prevalence of the neuropathogenic genotype of EHV1 in India. Out of 133 clinical specimens from abortion cases in northern India, 56 were positive for EHV1 infection. Analysis of the A/G SNP by real-time PCR and sequence analysis revealed that 54 of 56 samples (96.43 %) were of the non-neuropathogenic genotype (A2254), while two (3.57 %) had the neuropathogenic marker (G2254). Sequence analysis of the polymorphic region of ORF68 of EHV1 isolates (n = 9) from India indicated that the Delhi/1998, Tohana-2/2013, Hisar-2/2014 and Hisar-15/1990 isolates belonged to group 4, while the Jind/1996, Rajasthan/1998, Delhi-3/2007 and Tohana-5/1996 isolates clustered within group 5. One isolate (Hisar-7/1990) exhibited SNPs at positions C710and C713, forming a separate group. Here, we report for the first time the detection of neuropathogenic genotypes of EHV1 in India and show that Indian EHV1 isolates cluster within groups 4 and 5.
authors.affiliation: ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, 243122, India.
authors.forename: Gayathri
authors.initials: G
authors.lastname: Anagha
authors.affiliation: ICAR-National Research Centre on Equines, Hisar, Haryana, 125001, India. brgulati@gmail.com.
authors.forename: Baldev Raj
authors.initials: BR
authors.lastname: Gulati
authors.affiliation: ICAR-National Research Centre on Equines, Hisar, Haryana, 125001, India.
authors.forename: Thachamvally
authors.initials: T
authors.lastname: Riyesh
authors.affiliation: ICAR-National Research Centre on Equines, Hisar, Haryana, 125001, India.
authors.forename: Nitin
authors.initials: N
authors.lastname: Virmani
mesh_terms: D000034:Abortion, Veterinary / Q000453:epidemiology* / Q000821:virology; D000818:Animals; D016000:Cluster Analysis; D004196:Disease Outbreaks; D004679:Encephalomyelitis / Q000150:complications / Q000453:epidemiology / Q000662:veterinary*; D014644:Genetic Variation; D005838:Genotype; D006566:Herpesviridae Infections / Q000150:complications / Q000453:epidemiology / Q000662:veterinary*; D004861:Herpesvirus 1, Equid / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D006734:Horse Diseases / Q000453:epidemiology* / Q000821:virology; D006736:Horses; D007194:India / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D015995:Prevalence; D017422:Sequence Analysis, DNA