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Experiment ID
81
Pathogen
Shigella dysenteriae
Contains Preferred Model
0
Reference
The Response of Man to Virulent Shigella flexneri 2a
Host type
human
# of Doses
4.00
Μodel
beta-Poisson
a
2.77E-01
N50
2.38E+02
LD50/ID50
2.38E+02
Dose Units
CFU
Response
illness
Agent Strain
M 131
Exposure Route
oral (in milk)
Experiment Dataset
Description: 
Model data for Shigella dysenteriae (M 131) in the human [1]
Dose Illness Not illness Total
10 1 9 10
200 2 2 4
2000 7 3 10
1E+04 5 1 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 13.2 13.2 3 3.84 
0.000283		 7.81 
0.0042
Beta Poisson 0.0315 2 5.99 
0.984
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 2.77E-01 5.24E-03 1.10E-01 1.34E-01 1.63E+00 1.88E+01 1.72E+03
N50 2.38E+02 1.35E+01 4.73E+01 6.36E+01 1.42E+03 2.02E+03 5.89E+03

 

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.