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Experiment ID
80
Pathogen
Salmonella typhi
Agent Strain
Quailes
Contains Preferred Model
No
Reference
Levine, M. M., DuPont, H. L., Formal, S. B., Hornick, R. B., Takeuchi, A. ., Gangarosa, E. J., … Libonati, J. P. (1973). Pathogenesis of Shigella dysenteriae 1 (Shiga) Dysentery. Journal of Infectious Diseases, 127, 3.
Exposure Route
oral (in milk)
Response
disease
Host type
human
# of Doses
5.00
Dose Units
CFU
Μodel
beta-Poisson
a
2.03E-01
N50
8.53E+05
LD50/ID50
8.53E+05
Description
 Model data for S. Typhi (Quailes) in humans 
Dose Disease No disease Total
1000 0 14 14
1E+05 32 84 116
1E+07 16 16 32
1E+08 8 1 9
1E+09 40 2 42

 

Goodness of fit and model selection
Model Deviance Δ Degrees 
of freedom		 χ20.95,1 
p-value 		χ20.95,m-k 
p-value
Exponential 293 284 4 3.84 
0 		9.49 
0
Beta Poisson 8.63 3 7.81 
0.0346
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 2.03E-01 1.33E-01 1.49E-01 1.57E-01 2.74E-01 2.89E-01 3.27E-01
N50 8.53E+05 3.38E+05 4.28E+05 4.80E+05 1.62E+06 1.85E+06 2.49E+06

 

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

  • Hornick, R. B., Greisman, S. ., Woodward, T. E., DuPont, H. L., Dawkins, A. T., & Snyder, M. J. (1970). Typhoid fever: pathogenesis and immunologic control. The New England Journal of Medicine, 283, 13.