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Experiment ID
42
Pathogen
Escherichia coli
Agent Strain
ETEC O55 (in paper as “type 55, B5”)
Contains Preferred Model
No
Reference
June, R. ., Ferguson, W. ., & Worfel, M. . (1953). Experiments in feeding adult volunteers with Escherichia coli 55, B5, a coliform organism associated with infant diarrhea. American Journal of Hygiene, 57(2). https://doi.org/10.1093/oxfordjournals.aje.a119570
Exposure Route
oral
Response
slight to severe illness
Host type
human
# of Doses
4.00
Dose Units
CFU
Μodel
beta-Poisson
a
8.7E-02
N50
2.05E+05
LD50/ID50
2.05E+05
Experiment Dataset
Description
Escherichia coli (ETEC O55 (in paper as “type 55, B5”)) in the human model data 
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.
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
beta Poisson model plot, with confidence bounds around optimized model

References