Phylogenetic analysis of ovine herpes virus-2 (OHV-2) in malignant catarrhal fever infected cattle in AL-Qadisiyah of Iraq

Abstract

Ovine herpesvirus-2 is a member of the gammaherpesviruses of the herpeseviridae, which is the etiologic agent of malignant catarrhal fever (MCF), a significant fatal disease of cattle. MCF disease was diagnosed in native Iraqi cattle of AL-Qadisiyah governorate of Iraq, during the period from April 2014 and August 2016. Twenty three blood samples were collected from clinically suspected cattle. The presence of the virus in samples was ascertained based on clinical pictures, postmortem examination and molecular assays. Pansystemic involvement included respiratory, digestive, urinary, nervous systems and ocular lesions were described. A molecular analysis based on a tegument protein gene by specific semi-nested-PCR, DNA sequence and multiple alignments of all PCR products confirmed the Ovine herpesvirus-2 (OHV-2) infection, and revealed a single and double nucleotide deletion, insertion and substitutions,. Some of these mutations were non-silent, resulting in changes at the predicted amino acids level into viral tegument protein. The phylogenetic analysis showed the disease was caused by two genovariants of OHV-2 including at one cluster and were related to other sequences from others countries was analysed. MCF is sporadically occurring in cattle in Iraq, the head and eye form is more pronounced form. It has been concluded that study is provides valuable information about the genetic variation among the OHV-2 genotypes in Iraqi cattle. Based on sequence and phylogenetic analysis of tegument protein gene, this paper elucidated genetic relationship between identified Iraqi OHV-2 with other strains detected in other geographical regions. These results provide new information on the epidemiological and genetically of OHV-2 in Iraq.