Fenbendazole stimulates interferon secretion in calves during viral infection

Abstract

A total of six trials (five with live animals and one in vitro study) were conducted to evaluate the effects of fenbendazole (FBZ) on the immune response in stressed feedlot cattle. FBZ was given to all treatment calves at the recommended label dosage of 2.3 mg/lb (5 mg/kg) body weight. In Trial 1, treatment with FBZ did not affect serum neutralizing (SN) virus titers or viral shedding following inoculation with live, avirulent bovine herpes virus (BHV-1), but did increase titers for interferon (IFN) in nasal secretions at one, four and seven days post-inoculation. In Trial 2, FBZ-treatment reduced viral shedding and increased IFN titer in nasal secretions on days 4, 7 and 11 following inoculation with live, virulent bovine viral diarrhea virus (BVDV). In Trial 3, treatment with FBZ increased average daily gain ( P =0.11) and increased IFN titer in nasal secretions at two ( P =0.12) and seven ( P =0.07) days following intranasal vaccination with avirulent BHV-1. In naturally infected calves, control and FBZ-treated calves had greater nasal secretions of IFN compared to calves treated with morantel tartrate, levamisole, or thiabendazole (Trial 4). Treatment with FBZ did not increase weight gain or interferon secretions in response to vaccination with IBR and BVD viruses (Trial 5). In cell cultures treated with bluetongue virus, FBZ increased IFN titers. FBZ appears to stimulate IFN secretion in calves during experimental infection with either BHV-1 or BVDV (Trial 6).