P-90. Demonstration of high titred antibodies to infectious bovine rhinotracheitis virus in the sera of cattle by competition elisa

Infectious bovine rhinotracheitis (IBR) is one of the most important viral diseases of cattle and buffaloes that occurs throughout the world. It is caused by bovine herpes virus 1 (BHV-1) under the genus Varicello virus and family Herpesviridae. There are mainly three major clinical manifestations namely infectious pustular vulvovaginitis (IPV) in females and IBR and infectious pustular balanoposthitis (IPB) in males. It is a list B OIE disease which includes transmissible diseases that are considered to be of socio-economic and/or public health importance within the countries and that are significant in the international trade of animals and animal products. The disease is endemic in India and a number of cases have been reported by several workers previously. The Government of India has taken a step to screen all the breeding bulls for the disease before using the semen for in vitro fertilization (IVF) or natural or artificial insemination purposes. In this study, a total of 124 serum samples comprising of 52 Ongole female, 3 Ongole male, 3 Gir male, 64 Gir females and 2 Kankrej male animals received from Western Regional Disease Investigation Laboratory, Aundh, Pune were tested by competition ELISA using monoclonal antibodies to gB protein of BHV-1. The results were expressed as percent inhibition (P.I.) and a P.I. value of < 50% > 55% and 50–55% were considered as positive, negative and doubtful respectively for the presence of antibodies to BHV-1. 46/53 Ongole female, 2/3 Ongole male, 3/3 of Gir male, 54/64 Gir female and 2/2 Kankrej male were found positive for antibodies to BHV-1. Overall the female animals showed 86% positivity (100/116) to BHV-1 antibodies compared to 75% (6/8) positivity in male animals although the number of male animals (8) were less compared to females (116). When the Percent inhibition values (P.I.) were analysed, it was found that 4 male animals had the P.I. values below 5 and 2 had P.I. values in between 20–25. In case of female animals 91 animals had P.I. values below 10, six in between 20–25 and three in between 40–49 respectively. From this study, it is evident that most of the female and male animals harbouring the high titred antibodies to BHV-1 suggesting that these animals have been exposed to virus in their life time. As the BHV-1 has the property to produce latent infection in animals, the virus may be excreted through nasal and vaginal discharges and semen. The sero-positive animals may appear as healthy animals but under stress conditions virus may be excreted and other healthy animals of the herd may be infected. At present there is no vaccine available in the Indian market to immunize the animals against IBR. But time has come to think on the disease as it can cause productivity losses and reproductive problems. Further, large scale sero-epidemiological studies should be carried out to know the status of the disease in animals in India and accordingly the immunoprophylactic agents must be used to control the disease to a great extent.