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Experiment ID
42
Pathogen
Escherichia coli
Contains Preferred Model
0
Reference
Experiments in feeding adult volunteers with Escherichia coli 55, B5, a coliform organism associated with infant diarrhea
Host type
human
# of Doses
4.00
Μodel
beta-Poisson
a
8.7E-02
N50
2.05E+05
LD50/ID50
2.05E+05
Dose Units
CFU
Response
slight to severe illness
Agent Strain
ETEC O55 (in paper as “type 55, B5”)
Exposure Route
oral
Experiment Dataset
Description: 
Escherichia coli (ETEC O55 (in paper as “type 55, B5”)) in the human model data [1]
Dose Slight to severe illness No slight to severe illness Total
1.43E+08 6 2 8
1.73E+09 5 2 7
5.33E+09 6 2 8
1.6E+10 7 1 8

 

Goodness of fit and model selection
Model Deviance Δ Degrees 
of freedom		 χ20.95,1 
p-value		 χ20.95,m-k 
p-value
Exponential 35 34.5 3 3.84 
4.2e-09		 7.81 
1.21e-07
Beta Poisson 0.486 2 5.99 
0.784
Beta-Poisson fits better than exponential; cannot reject good fit for beta-Poisson.

 

Optimized parameters for the beta-Poisson model, from 10000 bootstrap iterations
Parameter MLE estimate Percentiles
0.5% 2.5% 5% 95% 97.5% 99.5%
α 8.7E-02 9.87E-04 1.02E-03 1.67E-02 3.57E-01 4.67E-01 7.83E-01
N50 2.05E+05 3.40E-09 4.31E-06 2.31E-04 1.30E+08 2.09E+08 5.13E+08

Parameter scatter plot for beta Poisson model ellipses signify the 0.9, 0.95 and 0.99 confidence of the parameters.

beta Poisson model plot, with confidence bounds around optimized model

References

  1. June, RC., Ferguson WW., & Worfel MT. (1953).  Experiments in feeding adult volunteers with Escherichia coli 55, B5, a coliform organism associated with infant diarrhea. American Journal of Hygiene. 57(2),