FURTHER INVESTIGATIONS ON THE EFFICACY OF A NONSPECIFIC DEFENSE INDUCER EVALUATED IN CALVES EXPOSED TO INFECTIOUS BOVINE-RHINOTRACHEITIS VIRUS

Six calves were given the immunomodulator Baypamun and housed together with another six calves of which, three were experimentally infected with bovine herpesvirus-1 (BHV-1), whereas the remaining three served as untreated controls, The three experimentally infected calves as wel l as the three controls developed clinical signs of the typical acute form of infectious bovine rhinotracheitis (IBR). Of the calves treated with Baypamun, those that had only one injection of the immunomodulat or, either at the start of the experiment (time 0) or 2 days later, un derwent a much milder form of IBR and recovered in a shorter time than the experimentally infected calves or the controls. The calves that r eceived four injections of the immunomodulator, i.e. at time 0 and sub sequently for the next 3 days, remained healthy throughout the 30 days of observation. Moreover, the virus shedding by the Baypamun treated calves was significantly reduced. It was speculated that the use of an immunomodulator, eventually associated with a vaccination programme, would be a feasible approach to reduce significantly the onset of outb reaks of BHV-1, one of the main infectious agent initiating the respir atory disease in cattle. (C) 1998 Elsevier Science Ltd. All rights res erved.