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Table 2 Diagnostic performance of different diagnostic procedures

From: Herd diagnosis of low pathogen diarrhoea in growing pigs – a pilot study

 

Hsen*

Hspe*

Hppv*

Hnpv*

Procedure 1: 1 of 4 qPCR-tested diarrhoeic pigs should be positive for L. intracellularis, B. pilosicoli, E. coli F4 and/or F18

0.96

0.35

0.82

0.76

Procedure 2: 1 of 4 qPCR-tested diarrhoeic pigs should be positive for L. intracellularis, B. pilosicoli, E. coli F4 and/or F18#

0.93

0.63

0.88

0.76

Procedure 3: 1 of 10 qPCR-tested diarrhoeic pigs should be positive for L. intracellularis, B. pilosicoli, E. coli F4 and/or F18

1.00

0.20

0.79

1.00

Procedure 4: 1 of 10 qPCR-tested diarrhoeic pigs should be positive for L. intracellularis, B. pilosicoli, E. coli F4 and/or F18#

1.00

0.60

0.88

1.00

Procedure 5: 2 of 10 qPCR-tested diarrhoeic pigs should be positive for L. intracellularis, B. pilosicoli, E. coli F4 and/or F18#

1.00

0.60

0.88

0.99

Procedure 6: Average number of diarrhoeic faecal pools per pen in the room should be ≥1.5, and the sum of L. intracellularis, B. pilosicoli,

0.96

0.72

0.91

0.85

E. coli F4 and F18 determined by qPCR in a pooled faecal sample containing five samples from diarrhoeic pigs should be ≥6,300 bacteria/g.

Procedure 7: Average number of diarrhoeic faecal pools per pen in the room should be ≥1.5, and the sum of L. intracellularis, B. pilosicoli,

1.00

0.66

0.90

1.00

E. coli F4 and F18 determined by qPCR in a pooled faecal sample containing 10 samples from diarrhoeic pigs should be ≥6,300 bacteria/g.

Procedure 8: Average number of diarrhoeic faecal pools per pen in the room should be ≥1.5, and the sum of L. intracellularis, B. pilosicoli,

0.83

0.86

0.95

0.63

E. coli F4 and F18 determined by qPCR in a pooled faecal sample containing five samples from random pigs should be ≥35,000 bacteria/g.

Procedure 9: Average number of diarrhoeic faecal pools per pen in the room should be ≥1.5, and the sum of L. intracellularis, B. pilosicoli,

0.94

0.81

0.94

0.82

E. coli F4 and F18 determined by qPCR in a pooled faecal sample containing ten samples from random pigs should be ≥35,000 bacteria/g.

Procedure 10: Average number of diarrhoeic faecal pools per pen in the room should be ≥1.5, and the sum of L. intracellularis, B. pilosicoli,

0.99

0.80

0.94

0.96

E. coli F4 and F18 determined by qPCR in a pooled faecal sample containing 20 samples from random pigs should be ≥35,000 bacteria/g.

Procedure 11: Average number of diarrhoeic faecal pools per pen in the room should be ≥2.5, and 2 of 10 qPCR-tested diarrhoeic pigs should be positive for L. intracellularis, B. pilosicoli, E. coli F4 and/or F18#

1.00

0.40

0.83

1.00

  1. *Hsen: Herd-level diagnostic sensitivity; Hspe: Herd-level specificity; Hppv: Herd-level positive predictive value; Hnpv: Herd-level negative predictive value.
  2. #The individual qPCR test for E. coli F18 and L. intracellularis was considered test-positive if a sample contained ≥5.2 log10 bacteria/g faeces.
  3. Diagnostic performance determined by computer simulation of 11 different diagnostic procedures used for demonstration of high pathogen diarrhoea outbreaks in growing pigs (all diagnostic procedures use qPCR testing as the only laboratory technique). Diagnostic procedure No. 10 was considered the best.
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Irish Veterinary Journal

ISSN: 2046-0481