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Table 2 Summarized clinical signs of SPF chickens infected with 106.0 EID50 of QX-like IBV strain SD at different ages.

From: Pathogenic characteristics of a QX-like infectious bronchitis virus strain SD in chickens exposed at different ages and protective efficacy of combining live homologous and heterologous vaccination

Group

Clinical signs

No Signs

Diarrhea

Sneezing

Nasal discharge

Tracheal rale

Dyspnea

Depression

Dead

1

1/30a

17/30

26/30

26/30

13/30

23/30

26/30

4/30

2

0/30

15/30

24/30

29/30

16/30

27/30

22/30

2/30

3

0/22

1/22

4/22

17/22

7/22

2/22

8/22

3/22

4

4/15

0/15

3/15

3/15

7/15

7/15

4/15

2/15

5

8/15

0/15

0/15

4/15

0/15

1/15

3/15

1/15

6

50/50

0/50

0/50

0/50

0/50

0/50

0/50

0/50

  1. Group 1, 2-weeks-old chickens infected with IBV strain SD. Group 2, 3-weeks-old chickens infected with IBV strain SD. Group 3, 8-weeks-old chickens infected with IBV strain SD. Group 4, 18-weeks-old chickens infected with IBV strain SD. Group 5, 22-weeks-old chickens infected with IBV strain SD. Group 6, control group.
  2. aNumber of chickens exhibiting clinical signs out of the total number of birds.