Wild ducks excrete highly pathogenic avian influenza virus H5N8 (2014–2015) without clinical or pathological evidence of disease

Figures & data

Health status and virus excretion of 32 wild ducks and four domestic chickens experimentally infected with highly pathogenic avian influenza virus A/chicken/Netherlands/emc-3/2014 (H5N8) GsGd clade 2.3.4.4 (group A, Buan-like)

			No. of birds that excreted virus from^a
			Pharynx		Cloaca
Common name (taxonomic name)	No. of birds	No. of birds with clinical signs	Virus isolation	PCR	Virus isolation	PCR
Eurasian wigeon (Anas penelope)	8	0	6	8	4	8
Common pochard (Aythya ferina)	8	0	5	8	0	8
Mallard (Anas platyrhynchos)	8	0	3	8	0	8
Common teal (Anas crecca)	8	0	6	8	3	8
Chicken (Gallus gallus)	4	4	4	4	4	4

The minimal detection limit of virus isolation was 0.5 TCID₅₀/ml and minimal area under the curve (AUC) from day 0 to 4 post inoculation was 2; if the values were on or below the minimal detection limit, birds were listed here as negative in the virus isolation

^aBetween 0 and 4 days post inoculation (dpi)

Fig. 1 Mean virus excretion via the pharynx of the highly pathogenic avian influenza virus A/chicken/Netherlands/emc-3/2014 (H5N8) GsGd clade 2.3.4.4 (group A, Buan-like) of wild ducks, based on virus isolation (a, b) and virus detection by reverse transcription-PCR (RT-PCR) (c, d) of all birds in the group. Eurasian wigeon (EUWI, circle), common pochard (COPO, square), mallard (MALL, triangle pointed up), and common teal (COTE, triangle pointed down). TCID₅₀, median tissue culture infectious dose with minimal detection limit of 0.5 TCID₅₀/ml; Ct cycle threshold. AUC, area under the curve summarizes virus excretion from day 0 to 4 post inoculation (mean ± 95% confidence interval) based on virus isolation (b) and virus detection by RT-PCR (d)

Fig. 2 Mean virus excretion via cloaca of the highly pathogenic avian influenza virus A/chicken/Netherlands/emc-3/2014 (H5N8) GsGd clade 2.3.4.4 (group A, Buan-like) of wild ducks, based on virus isolation (a, b) and virus detection by reverse transcription-PCR (RT-PCR) (c, d). Legend same as for Fig. 1

Level and duration of virus excretion of the highly pathogenic avian influenza virus A/chicken/Netherlands/emc-3/2014 (H5N8) GsGd clade 2.3.4.4 (group A, Buan-like) from the pharynx and cloaca in four duck species, based on virus isolation

	Height and duration of virus excretion per route
	Pharynx				Cloaca
Common name (taxonomic name)	AUC (mean ± SEM)	Median (dpi)	Peak (dpi)	Range (dpi)	AUC (mean ± SEM)	Median (dpi)	Peak (dpi)	Range (dpi)
Eurasian wigeon (Anas penelope)	7.2 ± 2.1	2.5	2.5	0–8	2.4 ± 0.3	1	3.5	0–5
Common pochard (Aythya ferina)	2.7 ± 0.3	1	1	0–4	2 ± 0	0	0	0
Mallard (Anas platyrhynchos)	2.7 ± 0.4	0	2	0–4	2 ± 0	0	0	0
Common teal (Anas crecca)	3.9 ± 1.0	2	2.5	0–4	2.3 ± 0.2	0	3	0–5

The minimal detection limit of virus isolation was 0.5 TCID₅₀/ml and minimal area under the curve (AUC) from day 0 to 4 post inoculation was 2. AUC, area under the curve summarizes infectious virus excretion from day 0 to 4 post inoculation; dpi, days post inoculation