Molecular detection and characterization of ovine herpesvirus-2 using heminested PCR in Pakistan

Abstract

Background Malignant catarrhal fever (MCF) is a highly fatal lymphoproliferative disease of cattle, deer, bison, water buffalo, and pigs caused by the gamma-herpesviruses alcelaphine herpesvirus-1 (AlHV-1) and ovine herpesvirus-2 (OvHV-2). Objectives This study aimed to determine the prevalence of OvHV-2 in sheep, goats, cattle, and buffalo in Rawalpindi and Islamabad, Pakistan, by applying molecular and phylogenetic methods. Methods Blood samples were aspirated from sheep (n = 54), goat (n = 50), cattle (n = 46) and buffalo (n= 50) at a slaughterhouse and several farms. The samples were subjected to heminested polymerase chain reaction (PCR), followed by sequencing and phylogenetic analysis of the OvHV-2 POL gene and the OvHV-2 ORF75 tegument protein gene. Results The highest percentage of MCF positive samples was in sheep (13%), whereas goat, cattle, and buffalo had lower positive percentages, 11%, 9%, and 6.5%, respectively. Four OvHV-2-positive PCR products obtained from sheep samples were sequenced. The sequences obtained were submitted to the NCBI GenBank database (MK852173 for the POL gene; MK840962, MK852171, and MK852172 for the ORF75 tegument protein gene). Phylogenetic analysis revealed a close similarity of study sequences with those of worldwide samples. Conclusions This study is the first cross-sectional study on the prevalence and molecular detection of OvHV-2 in apparently healthy cattle and buffalo that could be carrying OvHV-2 acquired from OvHV-2-positive sheep and goats. The results indicate that OvHV-2 is circulating in Pakistan. Further studies are needed to characterize OvHV-2 and elucidate further its prevalence.

Molecular epidemiolgy of ovine herpesvirus-2 in small ruminants, Sistan region, Iran

“…Based on the results of BLAST and phylogenetic analysis, the sequences obtained in this study showed approximately 98-100% similarity to other published sequences of the ORF75 tegument protein gene internationally. These ndings support other researchers' ndings that there is no major difference between OvHV-2 sequences globally [14,19,31].…”

“…Goats are natural hosts of caprine herpesvirus 2 (CpHV-2) [2,25]. However, as we detected OvHV-2 in this study, some evidence indicates that goats are reservoir hosts for OvHV-2 [17,19,26,27], because mixed farming is common in this region, OvHV-2 may be transmitted between sheep and goats without any speci c clinical signs. However, some studies have suggested that OvHV-2 can lead to subclinical infection in goats as well as exhibit clinical signs, such as fever and central nervous system disorders, such as ataxia and head tremors [28,29].…”

“…To date, cases of MCF occurrence have been reported in wild and domesticated animals in Iran [16][17][18]. Sistan and Baluchestan province situated in the south-eastern part of the country, which shares a border with Pakistan where MCF has also been reported [19]. There is no published document on the MCF situation in the province.…”

Viral Diseases in Water Buffalo (Bubalus bubalis): New Insights and Perspectives

“…Sheep-associated MCF occurs worldwide, and immunosuppression factors are necessary as precursors of this form [ 33 ]. A cross-sectional study on the prevalence and molecular detection of OvHV-2 in apparently healthy buffalo in Pakistan confirmed that they could be carrying OvHV-2 acquired from OvHV-2-positive sheep and goats [ 34 ].…”