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Experiment ID
79
Pathogen
Salmonella typhi
Contains Preferred Model
0
Reference
Typhoid fever: pathogenesis and immunologic control
Host type
human
# of Doses
3.00
Μodel
beta-Poisson
a
1.11E-01
N50
3.45E+06
LD50/ID50
3.45E+06"
Dose Units
CFU
Response
disease
Agent Strain
Quailes
Exposure Route
oral (in milk)
Experiment Dataset
Description: 
Model data for S. Typhi (Quailes) in humans [1]
Dose Disease No disease Total
1E+05 28 76 104
1E+07 15 15 30
1E+09 4 0 4

 

Goodness of fit and model selection
Model Deviance Δ Degrees 
of freedom		 χ20.95,1 
p-value		 χ20.95,m-k 
p-value
Exponential 124 121 2 3.84 
0		 5.99 
0
Beta Poisson 2.87 1 3.84 
0.0905
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 1.11E-01 3.19E-02 4.80E-02 5.49E-02 1.96E-01 2.17E-01 2.59E-01
N50 3.45E+06 4.81E+05 6.95E+05 8.50E+05 9.53E+07 2.24E+08 4.19E+09

 

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. Hornick, R. B., Woodward T. E., McCrumb F. R., Snyder M. J., Dawkins A. T., & Bulkeley J. T. (Submitted).  De la Macorra F and Corozza FA (1966) Study of induced typhoid fever in man. I. Evaluation of vaccine effectiveness. Transactions of the Association of American Physicians. 79, 361.