RESUMEN

The distribution and variance of respiratory disease produced with aerosols of bovine herpesvirus 1 (BHV-1) and Mannheimia haemolytica in control (183 calves in 44 experiments) and vaccinated calves were studied in experiments conducted at the Animal Diseases Research Institute, Lethbridge, Alberta, from 1975 to 1989. All calves had been born and raised at this institute and exposed similarly for 5 min by means of a face mask to viral and bacterial aerosols produced by a Collison atomizer (particles < 3 microm in diameter). We summarized the macroscopic pathological responses of pneumonia (main end point), tonsillitis, tracheitis, and other microbiologic and experimental variables. We also summarized the lobar distribution of pneumonia in 202 control and 192 vaccinated calves with this disease model and in calves similarly exposed to parainfluenza 3 virus/M. haemolytica or BHV-1/Pasteurella multocida. Pneumonia in control calves began in ventral tissues of all lobes, with lobar preferences, and progressed dorsally, the dorsal parts of both large caudal lobes being least affected. A high variance of pneumonia was evident within and among experiments. From the magnitude of variance observed in the control groups, the number of calves per group required in vaccine-challenge studies using this BHV-1/M. haemolytica disease model was estimated. Such estimates are required for any disease model used in vaccine-challenge studies.

Asunto(s)

Enfermedades de los Bovinos/prevención & control , Infecciones por Herpesviridae/veterinaria , Herpesvirus Bovino 1/inmunología , Mannheimia haemolytica/inmunología , Infecciones por Pasteurella/veterinaria , Vacunación/veterinaria , Aerosoles , Animales , Bovinos , Enfermedades de los Bovinos/patología , Femenino , Infecciones por Herpesviridae/patología , Infecciones por Herpesviridae/prevención & control , Pulmón/microbiología , Pulmón/patología , Pulmón/virología , Infecciones por Pasteurella/patología , Infecciones por Pasteurella/prevención & control , Distribución Aleatoria , Infecciones del Sistema Respiratorio/patología , Infecciones del Sistema Respiratorio/prevención & control , Infecciones del Sistema Respiratorio/veterinaria , Tamaño de la Muestra , Organismos Libres de Patógenos Específicos

RESUMEN

A high incidence of foreign-body pneumonia was found in an institutional swine herd. Foreign material of plant origin was found in 40 of 68 lungs. Most of the foreign matter was of feed origin but four particles of wood were demonstrated. Numerous particles up to 50 µm wide were found in alveoli, and particles as large as 300 µm were found in bronchioles. Lungs of four control animals were used to study the histological reaction to the inhaled foreign bodies. Polymorphonuclear leucocytes, macrophages, and giant cells were the principal cell types associated with the plant particles. Hyperplasia and destruction of respiratory epithelium and lymphoreticular proliferation were also noted.