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Experiment ID
81, 215
Pathogen
Shigella dysenteriae
Contains Preferred Model
0
Reference
Pathogenesis of Shigella dysenteriae 1 (Shiga) Dysentery
Host type
human
# of Doses
6.00
Μodel
beta-Poisson
a
4.93E-03
N50
3.64E-01
LD50/ID50
3.64E-01
Dose Units
CFU
Response
illness
Agent Strain
M 131
Exposure Route
oral (in milk)
Experiment Dataset
Description: 
Model data for Shigella dysenteriae in the human [1]
Dose Illness Not illness Total
10 1 9 10
200 2 2 4
200 1 3 4
2000 7 3 10
1E+04 5 1 6
1E+04 2 4 6

 

Goodness of fit and model selection
Model Deviance Δ Degrees 
of freedom		 χ20.95,1 
p-value		 χ20.95,m-k 
p-value
Exponential 30.5 16.9 5 3.84 
3.94e-05		 11.1 
1.2e-05
Beta Poisson 13.6 4 9.49 
0.00887
Neither the exponential nor beta-Poisson fits well; beta-Poisson is less bad.

 

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 4.93E-03 9.85E-04 9.87E-04 9.88E-04 3.61E-01 4.26E-01 5.85E-01
N50 3.64E-01 2.07E-02 5.54E-02 7.42E-02 2.05E+03 4.61E+03 1.09E+28

 

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. Levine, M. M., DuPont H. L., Formal S. B., Hornick R. B., Takeuchi A., Gangarosa E. J., et al. (1973).  Pathogenesis of Shigella dysenteriae 1 (Shiga) Dysentery. Journal of Infectious Diseases. 127, 3.