Changing Patterns of H6 Influenza Viruses in Hong Kong Poultry Markets

Table 5

Experimental infection of quails and chickens.

Virus	QID^a50	CID^a50
Domestic poultry isolates
2001 isolates
Qa/HK/CSW106/01 (H6N1)	3.00	5.00
Ck/HK/SF4/01 (H6N1)	3.92	4.17
Sc/HK/AP46/01 (H6N2)	3.63	5.08
2002 isolates
Ph/HK/SSP44/02 (H6N1)	2.20	4.58
Qa/HK/YU404/02 (H6N1)	2.50	4.75
Gf/HK/SSP99/02 (H6N2)	3.23	4.73
2003 isolates
Ch/HK/CSW595/03 (H6N1)	2.73	4.73
Aquatic wild-bird isolates
2001 isolate
Dk/ST/5540/01 (H6N2)	2.6	6.48
2003 isolate
He/HK/LC10/03 (H6N8)	3.17	7.92
Reference strain
1997 isolate
Tl/HK/W312/97 (H6N1)	3.47	4.92

^aQID₅₀ and CID₅₀ indicate 50% quail and chicken infectious dose, respectively (log₁₀EID₅₀/0.1 ml). Each titer was obtained from tracheal swabs of animals at 3-day postinoculation.