RESUMEN
An immunohistochemical staining technique (IHC) was developed to detect avian pneumovirus (APV) antigen in formalin-fixed, paraffin-embedded tissue sections using streptavidin-biotin immunoperoxidase staining. Samples of nasal turbinates and infraorbital sinuses were collected from 4-week-old poults experimentally inoculated with APV and from older turkeys infected during naturally occurring outbreaks of avian pneumovirus. Tissue was fixed in 10% buffered neutral formalin, embedded in paraffin, sectioned and stained. Inflammatory changes were observed microscopically in the mucosa and submucosa of the nasal turbinates and infraorbital sinuses of both experimentally inoculated poults and naturally infected birds. Viral antigen was detected by IHC in the ciliated epithelial cells of nasal turbinates and infraorbital sinuses.
Asunto(s)
Infecciones por Pneumovirus/veterinaria , Pneumovirus/aislamiento & purificación , Enfermedades de las Aves de Corral/diagnóstico , Animales , Antígenos Virales/análisis , Femenino , Formaldehído , Inmunohistoquímica , Masculino , Mucosa Nasal/virología , Pneumovirus/inmunología , Infecciones por Pneumovirus/diagnóstico , Conejos/inmunología , Fijación del Tejido , PavosRESUMEN
Avian pneumovirus (APV) is an emerging viral respiratory disease agent of turkeys in Minnesota. Clinical signs of APV infection include open mouth breathing, ocular and nasal discharge, and swelling of infraorbital sinuses. The virus spreads rapidly among flocks of susceptible turkeys and is associated with increased mortality rates. A flock of 11-wk-old turkeys experienced a respiratory problem characterized by coughing, sneezing, swollen sinuses, and nasal discharge. The reverse transcriptase-polymerase chain reaction (RT-PCR) performed on tissues from the nasal turbinates and tracheal tissues was positive for avian pneumovirus. Turbinate tissue was inoculated into chicken embryo fibroblasts, and cytopathic effect was observed after five blind passages. In an attempt to reproduce the disease, 50 microl of this cell culture-propagated virus was instilled into each conjunctival space and nostril of 23-day-old turkey poults. The poults were sacrificed at 2-day intervals for 12 days, and serum, tissues, and tracheal and cloacal swabs were collected. Between days 2 and 10 after exposure, the poults developed ocular and nasal discharge and swollen sinuses. The virus was detected by RT-PCR and virus isolation from the nasal turbinates of poults sacrificed on days 4 and 6 postinoculation. Antibodies to APV were detected by enzyme-linked immunosorbent assay.