Table 4.

Average distribution of AIV-NP antigen in positive tissues from quail intranasally challenged with H5N1/HP

Tissue*	3 dpi	4 dpi	5 dpi	6 dpi	7 dpi	Predominant cell types	Associated lesion
Proventriculus	–	–	–	+	–	Epithelial cells of the proventricular glands, cells of the muscularis externa	Severe multifocal necrosis, mild lymphoplasmacytic infiltrate
Gizzard	–	–	+	++	++	Epithelial cells of the ventricular glands, cells of the muscularis externa	Severe multifocal necrosis, mild lymphoplasmacytic infiltrate
Cecal tonsil	–	–	+	+++	+	Cells of the lamina propria	Mild lymphoplasmacytic infiltrate
Rectum	–	–	–	+	+	Cells of the muscularis externa of the lamina propria	Vacuolation, degeneration, mild lymphoplasmacytic infiltrate
Pancreas	+	–	++	++	+	Acinar cells, endothelial cells	Severe multifocal to coalescent lytic necrosis, lymphoplasmacytic infiltrate, edema
Kidney	+	+	+	+	+++	Collecting tubular epithelial cells, endothelial cells	Moderate to severe necrosis, mild lymphoplasmacytic infiltrate
Adrenal gland	+	–	–	–	–	Corticotrophic and corticotropic cells	NSL
Nasal turbinates	–	++	–	–	–	Respiratory epithelial cells	Lymphoplasmacytic infiltrate in lamina propria
Heart	+	++	+++	++	+++	Myocardiocytes, endothelial cells	Severe multifocal necrosis, mild lymphoplasmacytic infiltrate
Skeletal muscle	–	–	+	++	++	Myocytes, endothelial cells	Moderate multifocal necrosis, mild lymphoplasmacytic infiltrate
Spleen	–	–	–	–	+	Endothelial cells, macrophages	NSL
Brain	++	+++	+++	+++	+++	Neurons, Purkinje cells, ependymal cells, glial cells, endothelial cells	Malacia in cortex, necrosis of ependymal cells of ventricles and epithelial cells of choroid plexus, chromatolysis of Purkinje cells, lymphoplasmacytic infiltrate.

*Tissues not present appeared overtly normal on histopathological analysis and did not show positive IHC staining.

– = no positive cells; + = single positive cells; ++ = scattered groups of positive cells; +++ = widespread positivity.

dpi, days post-inoculation; NSL, no significant lesions.