Table 2.

Expression of AIV antigen in cell types of different organs of the respiratory and gastro-intestinal tracts

Species	No of birds	Number of birds expressing influenza virus antigen in a cell type of an organ
		Respiratory tract						Gastro-intestinal tract
		Lung			Air sac			Proventriculus			Small intestine			Large intestine
		EP	E	N	EP	E	N	EP	E	N	EP	E	N	EP	E	N
Tufted duck Aythya fuligula	7	1	4	0	0	1	0	1∞	2	2	1∞	4	1	0	4	0
Common pochard Aythya farina	1	0	0	0	0	0	0	0	0	0	0	0	1	0	0	0
Great crested grebe Podiceps cristatus	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Eurasian teal Anas crecca	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Eurasian wigeon Mareca Penelope	10	5	6	1	2	5	0	2∞	7	0	3∞*	8	1	1*	8	0
Mallard Anas platyrhynchos	2	0	0	0	1	0	0	0	1	0	1	1	1	0	1	0
Duck (unspecified species)	10	8	0	0	8	0	0	0	3	0	0	2	1	0	3	1
Greylag goose Anser anser	1	0	0	0	0	1	0	1	0	0	0	0	0	0	0	0
Great black backed gull Larus marinus	1	0	1	0	1	1	0	0	0	0	0	1	0	0	1	0
Lesser black backed gull Larus fuscus	1	1	0	0	1	0	0	0	0	0	0	0	0	0	0	0
Black-headed gull Chroicocephalus ridibundus	1	0	1	0	1	0	0	1	1	0	0	1	1	0	1	1
Eurasian buzzard Buteo buteo	2	0	1	0	0	0	0	0	0	0	0	0	0	0	0	0
Eurasian magpie Pica pica	1	1	0	0	1	0	0	1	0	0	1	0	0	1	0	0
Total	39	16	13	1	15	8	0	6	14	2	6	17	6	2	18	2

Ep epithelial cell, E endothelial cell, N neuron.

∞ One bird expressed influenza virus antigen in the epithelial cells of both proventriculus and small intestine.

*One bird expressed influenza virus antigen in the epithelial cells of both small and large intestine.