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Table 1 Study 1: Mortality, mean death time (MDT), oropharyngeal (OP) and cloacal (CL) virus shedding in chickens inoculated with NDV and HPAIV

From: Previous infection with virulent strains of Newcastle disease virus reduces highly pathogenic avian influenza virus replication, disease, and mortality in chickens

Virus

Number of dead/total (MDT)

OP shedding: number of birds shedding/total (Log 10 EID 50 /mL) a

CL shedding: number of birds shedding/total (Log 10 EID 50 /mL) a

NDV

HPAIV

NDV

HPAIV

1 dpi

2 dpi

1 dpi

2 dpi

1 dpi

2 dpi

1 dpi

2 dpi

lNDV

0/10

10/10 (5.3 ± 0.1)A

10/10 (6.1 ± 0.1)A

nd

nd

1/10 (1.6)A

5/10 (3.3 ± 0.08)A

nd

nd

mNDV

0/10

7/10 (2.9 ± 0.4)A

10/10 (3.2 ± 0.1)A

nd

nd

0/10 (0)A

0/10A

nd

nd

vNDV low dose

10/10 (5.2)

10/10 (4.4 ± 0.1)A

10/10 (5.9 ± 0.1)A

nd

nd

0/10 (0)A

8/10 (3.8 ± 0.2)A

nd

nd

vNDV high dose

10/10 (4.4)

10/10 (3.6 ± 0.1)A

10/10 (6.4 ± 0.1)A

nd

nd

0/10 (0)A

10/10 (5.2 ± 0.1)A

nd

nd

HPAIV

10/10 (2.0)

nd

nd

10/10 (4.6 ± 0.1)A

2/2 (5.7 ± 0.1)A

nd

nd

8/10 (3.1 ± 0.3)A

2/2 (4.9 ± 0.3)A

lNDV + HPAIV

10/10 (2.3)

9/10 (4 ± 0.1)B

5/10 (4.5 ± 0.1)*B

9/10 (4.6 ± 0.1)A

5/5 (6 ± 0.1)A

0/10 (0)A

0/5B

8/10 (2.7 ± 0.3)A

5/5 5.6 ± 0.2)B

mNDV + HPAIV

10/10 (2.2)

2/10 (1.8 ± 0.04)*A

1/3 (2.2)*B

10/10 (4.2 ± 0.1)A

3/3 (5.9 ± 0.3)A

0/10 (0)A

0/3A

8/10 (2.4 ± 0.2)A

3/3 (5.4 ± 0.03)A

vNDV low dose + HPAIV

10/10 (2.4)

5/10 (4.2 ± 0.2)*A

5/5 (4.7 ± 0.1)B

10/10 (4.5 ± 0.1)A

5/5 (5.8 ± 0.2)A

0/10 (0)A

0/5**B

7/10 (2.5 ± 0.4)A

5/5 (5.5 ± 0.2)A

vNDV high dose + HPAIV

10/10 (2.1)

10/10 (4.6 ± 0.3)B

3/3 (6.3 ± 0.1)A

10/10 (4.3 ± 0.1)A

3/3 (6.4 ± 0.3)A

0/10 (0)A

0/3**B

7/10 (2.5 ± 0.4)A

3/3 (5.5 ± 0.2)A

lNDV + HPAIV 2 days later

10/10 (2.6)

10/10 (3.9 ± 0.1)A

7/7 (6.6 ± 0.2)A

10/10 (4.5 ± 0.2)A

7/7 (5.9 ± 0.2)A

2/10 (2.1 ± 0.01)A

0/7*A

7/10 (2.3 ± 0.4)A

7/7 (5.3 ± 0.04)A

mNDV + HPAIV 2 days later

10/10 (3.1)

7/10 (2.4 ± 0.2)A

7/9 (3.1 ± 0.1)A

10/10 (3.8 ± 0.2)A

9/9 (5.8 ± 0.1)A

4/10 (1.8 ± 0.1)B

5/9 (3.2 ± 0.2)*B

10/10 (3.1)A

9/9 (5.2 ± 0.04)A

vNDV low + HPAIV 2 days later

10/10 (2.5)

10/10 (6.4 ± 0.1)B

7/7 (7.6 ± 0.1)B

3/10 (1.5 ± 0.7)**B

7/7 (5.3 ± 0.1)A

10/10 (5.5 ± 0.1)***B

7/7 (7.1 ± 0.1)B

0/10***B

7/7 (5.3 ± 0.05)A

vNDV high + HPAIV 2 days later

10/10 (1.9)

10/10 (6.8 ± 0.1)B

2/2 (8.0 ± 0.3)B

3/10 (2.1 ± 0.1)**B

2/2 (5.3 ± 0.1)A

10/10 (6.3 ± 0.1)***B

2/2 (7.6 ± 0.3)B

0/10***B

2/2 (5.3 ± 0.05)A

  1. For groups inoculated sequentially with the viruses, HPAIV titers are from 1 or 2 days after HPAIV inoculation, which corresponds to days 3 and 4 after NDV inoculation.
  2. aViral titers average ± SEM (standard error mean) from the positive birds; Log10 EID50 equivalents were determined by qRRT-PCR. nd = not done. *Significant difference in number of chickens virus positive compared to single virus infected groups (*P < 0.01; **P < 0.001; ***P < 0.0001).
  3. A;BDifferent superscript uppercase denote significant difference in virus titers compared to single virus-infected groups (P < 0.05).