[Induction of interferon activity in nasal mucus by association of levamisole by systemic route -- inactivated virus by local route (author's transl)].

Calf respiratory disease could have a non-specific origin. The respiratory tract bacterial flora is pathogen only if the animal faces stress which decreases the defense capacities of the respiratory mucosa. The simultaneous administration of UV irradiated IBR virus by nasal route and of levamisole by systemic route induces a protection which is accompanied by interferon synthesis in the nasal mucus. This protection is evaluated experimentally with an infectious IBR virus challenge. In the natural conditions the respiratory disease loses its transmissible aspect in the treated calves.