HA gene amino acid mutations contribute to antigenic variation and immune escape of H9N2 influenza virus

Table 1 Virus shedding from the swabs on Days 3 and 5 after challenge with F/98 or rF/HA_A180V viruses.

Group	Virus shedding¹		Protection (%)
Group	D3	D5	Protection (%)
Chickens vaccinated the F/98 inactive vaccine
Challenged with the F/98 virus	0/6^a	0/6^a	100
Challenged with the rF/HA_A180V virus	1/6^a	0/6^a	83.3
Chickens vaccinated the rF/HA_A180V inactive vaccine
Challenged with the F/98 virus	1/6^a	0/6^a	83.3
Challenged with the rF/HA_A180V virus	1/6^a	0/6^a	83.3

The positive sample of chickens shedding virus indicated higher than the detection limit of the 2² HA titre, whereas protection was calculated with data on Day 3.
^aThe appearance of the same letter means there is no marked difference among the groups under the condition of P > 0.05.
¹Data consist of numbers of chickens shedding virus/total number of chickens at Days 3 and 5.

ISSN: 1297-9716