Infectivity and transmissibility of H9N2 avian influenza virus in chickens and wild terrestrial birds

Table 4 HI titres of sera collected from UDL-01/08 virus infected and contact birds

Species	Infection route	Pre-infection HI titre	7 dpi	14 dpi	Day 21 dpi	28 dpi
			Number of birds positive for HI / total birds
			log₂HI titer range (GMT)
Broiler	Infected	<2	10/10	10/10	10/10	10/10
	Infected	<2	5–8 (6.2)	7–9 (8.0)	8–9 (8.4)	8–9 (8.4)
	Contact	<2	5/5	5/5	5/5	5/5
	Contact	<2	3–6 (4.1)	5–7 (5.7)	8–9 (8.3)	8–10 (8.9)
Layer	Infected	<2	10/10	10/10	10/10	10/10
	Infected	<2	5–8 (6.1)	7–9 (8.0)	8–9 (8.4)	8–9 (8.6)
	Contact	<2	0/5	5/5	5/5	5/5
	Contact	<2	<2	5–7 (6.0)	8–9 (8.4)	8–9 (8.4)
Jungle fowl	Infected	<2	9/10	10/10	10/10	10/10
	Infected	<2	7–9 (7.5)	9–10 (9.1)	9–10 (9.6)	9–10 (9.6)
	Contact	<2	0/5	5/5	5/5	5/5
	Contact	<2	<2	6–8 (7.4)	9–10 (9.6)	9–10 (9.6)
Quail	Infected	<2	8/8	8/8	8/8	8/8
	Infected	<2	6–8 (7.5)	7–10 (8.6)	8–10 (8.9)	9–10 (9.4)
	Contact	<2	0/5	5/5	5/5	5/5
	Contact	<2	<2	7–9 (7.8)	8–9 (8.6)	8–9 (8.6)
Sparrow	Infected	<2	10/10	10/10	10/10	10/10
	Infected	<2	5–8 (6.5)	7–9 (8.2)	8–10 (8.8)	9–10 (9.7)
	Contact	<2	0/5	5/5	5/5	5/5
	Contact	<2	<2	7–9 (7.6)	8–10 (8.8)	8–9 (8.1)
Crow	Infected	<2	0/10	0/10	10/10	10/10
	Infected	<2	<2	<2	4–9 (6.9)	5–9 (7.7)
	Contact	<2	0/5	0/5	0/5	0/5
	Contact	<2	<2	<2	<2	<2

GMT, Geometric mean titers; dpi, days post infection. HI titres <2 were regarded as baseline detection and were considered negative for seroconversion. Infected birds were inoculated with 10^6.6 EID₅₀ UDL-01/08 virus. Swab samples were inoculated into EHE and virus was detected by HA assay. Contact birds are indicated in bold.

ISSN: 1297-9716