Genetic Variation of the Causal Agent of Sheep-Associated Malignant Catarrhal Fever in Buffalo in Indonesia: Using a Repeat-Sequence Polymerase Chain Reaction

Abstract

A study on the genetic variation of Ovine Herpesvirus-2 (OVH-2), the causal agent of sheep-associated malignant catarrhal fever (SA-MCF), in buffalo in Indonesia using a repeat-sequence polymerase chain reaction (RS-PCR) has been conducted. Samples of heparinized blood and/or pre-scapular or pre-femoral lymph nodes were received from buffaloes that were occasionally slaughtered in private slaughterhouses in the District of Bogor. Butchers were requested to collect samples from buffaloes showing at least one of the clinical signs of an MCF such as febrile, diarrhoea, conjunctivitis, serous to mucopurulent ocular and nasal discharges and enlargement of superficial lymph nodes. A total of 21 specimens of white blood cells (WBC) were extracted and tested by a conventional SA-MCF polymerase chain reaction (PCR) to diagnose SA-MCF and subsequently tested by an RS-PCR. Based on the PCR and RS-PCR results, genetic variation of the causal agent of SA-MCF in buffalo was visually observed. The RS-PCR results were then confirmed using Southern blot hybridization analysis and also using restriction enzyme profiling. The results showed that genetic variation of the causal agent of SA-MCF in buffalo was found in 21 buffalo that were tested. The variables were grouped into two main groups A and B consisting of 12 and 9 buffalo respectively. Group A was further divided into two sub-groups A1 and A2 consisting of 9 and 3 buffalo respectively. Southern blot hybridization analysis and restriction enzyme profiling confirmed the RS-PCR results. The study concludes that genetic variation of the causal agent of SA-MCF was observed in 21 buffaloes that were tested. However, the significance of the genetic variation of the causal agent of SA-MCF in the pathogenesis of the disease in buffaloes has yet to be studied.