PCR detection of ovine herpesvirus-2 DNA in Indonesian ruminants — normal sheep and clinical cases of malignant catarrhal fever

Abstract

Malignant catarrhal fever (MCF), a fatal viral disease of cattle and other large ruminants, has a worldwide distribution. There are two forms of the disease, one of which, is caused by Alcelaphine herpesvirus-1 (AHV-1) and is derived from wildebeest. The other form is associated with domestic sheep and is caused by ovine herpesvirus-2 (OHV-2). The disease in Indonesia is sheep-associated with the preferred livestock of this area, Balinese cattle ( Bos javanicus) and water buffalo ( Bubalus bubalis), both highly susceptible to SA-MCF. The incidence in these species is thought to be high but the prevalence and economic losses attributable to SA-MCF have been difficult to assess. A polymerase chain reaction (PCR) test, based on a cloned OHV-2 gene sequence, was successfully applied to the detection of OHV-2 DNA in normal sheep and animals affected with SA-MCF. OHV-2 DNA was detected in eleven confirmed cases of SA-MCF and in the peripheral blood leucocyte (PBL) fraction of six latently infected sheep. These findings have confirmed that the PCR can be of value in establishing a diagnosis of MCF and that the aetiological agent of MCF in Indonesia is OHV-2. The amplification of DNA from the PBL of goats suggests that they are infected with a similar or identical herpesvirus.