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Safety & Health

Health Consequence Scoring for Biological Contaminants in Animal Feed

Health Consequence Scoring for Biological Contaminants in Animal Feed

Phares O. Okelo, Ph.D.
U.S. Food and Drug Administration

Prepared for presentation at the
Center for Veterinary Medicine (CVM)
Animal Feed Safety System (AFSS) Public Meeting
Rockville, MD
September 12, 2006

Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 1

Slide 2

B-HCS = B-PS x B-SS

B-HCS = Biological Health Consequence Score
B-PS = Biological Potency Score
B-SS = Biological Severity Score 

Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 2

Slide 3

Likelihood of Illness (B-PS)

If a person or animal is exposed to a hazardous biological agent, what is the likelihood of illness? 

Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 3

Slide 4

Likelihood of Illness (B-PS) Factors

  • Median Infective Dose (B-PSMID)
  • Infective Dose Range
     (B-PSIDR)
     
Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 4

Slide 5

Median Infective Dose (B-PSMID)Scoring

 

Median Infective Dose (MID) (CFU)Score
Small (1-102)3
Medium (102.1–105)2
Large (>105)1
Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 5

Slide 6

Infective Dose Range (B-PSIDR) Scoring

Infective Dose Range (IDR) (log CFU)Score
Small (0.1-2)3
Medium (2.1–5)2
Large (>5)1
Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 6

Slide 7

B-HCS = B-PS x B-SS

B-HCS = Biological Health Consequence Score
B-PS = Biological Potency Score
B-SS = Biological Severity Score

Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 7

Slide 8

Severity of Illness (B-SS)

  • If a person or animal is exposed to the hazardous agent and becomes ill, how severe will the illness be?

    • Loose/watery stool - Salmonella enterica
Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 8

Slide 9

Severity of Illness (B-SS) Factors

  • Major signs/symptoms

    • contaminating pathogens considered
    • animal type
Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 9

Slide 10

Sign/symptom Scoring

Signs (Swine: S. enterica, E. coli, Clostridium spp.)Mean Sign Score (MSS, 1-5)
abortion

anorexia 

depressed daily weight gain 

 
Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 10

Slide 11

B-HCS = B-PS x B-SS

B-HCS = Biological Health Consequence Score
B-PS = Biological Potency Score
B-SS = Biological Severity Score  

Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 11

Slide 12

Swine: B-HCS Scoring

 

Signs (Swine) Mean Sign Severity Score (MSS, 1-5) S. enterica 
E. coli
 
Clostridium spp. 
  Appearance Score (A = 0 or 1)  
abortion 3.0 0 0
anorexia 2.0  0
e.t.c. (additional signs) . .
Severity of Illness (B-SS) = sum(MSSxA)  49.7 39.7  58.7
B-PSMID (MID: Low, 3 / Med., 2 / High,1)   1
B-PSIDR (IDR:   Small, 3 /  Med., 2 / Large, 1)   1
HCS = [B-PSMID x B-PSIDR] x B-SSMSS
 
 49.7  58.7
HCS Ranking   2
 
Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 12

Slide 13

Humans: B-HCS Scoring

 

Signs/symptoms (Humans) Mean Sign Severity Score (MSS, 1-5) S. enterica 
E. coli
 
Clostridium spp. 
  Appearance Score (A = 0 or 1)  
abdominal cramps2.3 1 1
acute renal failure3.3  0
e.t.c. (additional signs and symptoms). .
Severity of Illness (B-SSMSS) = sum(MSSxA) 40.041.7  10.7
B-PSMID (MID: Low, 3 / Med., 2 / High,1)   1
B-PSIDR (IDR:   Small, 3 /  Med., 2 / Large, 1)   1
HCS = [B-PSMID x B-PSIDR] x B-SSMSS
 
 40.0 375.3 
10.7
HCS Ranking   3
 
Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 13

Slide 14

Future considerations

  • Continue gathering field data
  • Refine the model
  • Validate
  • Test
     
Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 14

Slide 15

Summary

  • Need for B-HCS model to assess relative risk
  • Two factors - B-PS and B-SS were used in the model
  • Various factors considered (B-PSMID, B-PSIDR, B-SSMSS)
  • Based on published data, the approach appears reasonable
  • Continuous assessment 
Health Consequence Scoring for Biological Contaminants in Animal Feed - Slide 15