Molecular Detection and Identification of Ovine Herpesvirus-۲ in Small Ruminants, Sistan Region, Iran

Introduction: Malignant catarrhal fever (MCF) is a fatal disease affecting susceptible livestock species. Ovine herpesvirus-۲ (OvHV-۲), the main causative agent of sheep-associated MCF, establishes asymptomatic infections in sheep and goats, which serve as reservoir hosts. This study investigated the molecular prevalence of OvHV-۲ in small ruminants from the Sistan region of southeastern Iran.Materials & Methods: Blood samples were collected from ۱۰۰ clinically healthy animals, including ۴۸ sheep and ۵۲ goats, from traditional husbandry systems in the Sistan region. DNA extracted from buffy coat samples was analyzed using heminested chain reaction (PCR) targeting the OvHV-۲ POL and ORF۷۵ genes. Selected positive samples were sequenced and subjected to phylogenetic analysis. Associations between infection and potential risk factors were evaluated using logistic regression.Results: OvHV-۲ DNA was detected in ۱۵% (۱۵/۱۰۰) of the animals, including ۱۶.۷% (۸/۴۸) of sheep and ۱۳.۵% (۷/۵۲) of goats. No significant association was found between infection and species, age, sex, or geographical location. However, flock size was significantly associated with virus prevalence (P<۰.۰۵). Sequence analysis of the ORF۷۵ gene showed ۱۰۰% identity with isolates previously reported from Pakistan, Brazil, Turkey, Egypt, and India, indicating high genetic conservation.Conclusion: OvHV-۲ is circulating among sheep and goats in the Sistan region and may contribute to the risk of MCF in susceptible livestock. This study provides the first molecular evidence of OvHV-۲ infection in small ruminants from the region and highlights the importance of management practices, particularly separation of reservoir and susceptible species, for disease control.

کلیدواژه ها:

Goats ، Malignant catarrhal fever (MCF) ، Ovine herpesvirus-۲ (OvHV-۲) ، Sheep ، Sistan