Sensitive detection of genomic DNA of BHV-1 in semen samples of bulls by polymerase chain reaction

Artificial insemination in cows and buffalo cows with exotic and superior germplasm is commonly practiced in India to enhance the productivity of the animals and to improve the indigenous germplasm. Due to the adoption of cross breeding programmes, a number of diseases are also transmitted and the infectious bovine rhinotracheitis (IBR)/infectious pustular balanoposthitis (IPB)/infectious pustular vulvovaginits (IPV) caused by the bovine herpes virus 1 (BHV-1) is the notable one. Besides causing the respiratory and reproductive symptoms in animals, BHV-1 also causes latent infections, a unique feature of the disease. The latent virus may be established in the trigeminal ganglion in IBR and sacral ganglia in IPB/IPV. The latently infected animals excrete the virus in the semen intermittently and particularly under stress conditions induced by transport or corticosteroid treatment. There is an urgent need to screen the semen samples of every batch randomly to prevent the spread of the virus to inseminated cattle and buffaloes through semen. In the present study, a total of 1038 semen samples of different farms of India have been screened by Polymerase Chain Reaction (PCR) using the primer set specific for gene coding for the gI protein of BHV-1. Out of 1038 samples tested only 30 samples were found to be positive for genomic DNA of BHV-1. This technique was found to be highly sensitive, rapid and specific and provide the result in 6 hours only unlike the virus isolation in cell culture system which is less sensitive and needs more time compared to PCR.