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Experiment ID
301
Pathogen
Rickettsia rickettsi
Agent Strain
Sheila Smith
Contains Preferred Model
No
Reference
DuPont, H. ., Hornick, R. ., Dawkins, A. ., Heiner, G. ., Fabrikant, I. ., , & Woodward, T. . (1973). Rocky Mountain spotted fever: a comparative study of the active immunity induced by inactivated and viable pathogenic Rickettsia rickettsii. Journal of Infectious Diseases, 128, 340–344.
Exposure Route
intradermal
Response
clinical signs
Host type
human
# of Doses
3.00
Dose Units
CFU
Μodel
beta-Poisson
a
6.75E-01
N50
2.36E+01
LD50/ID50
2.36E+01
Description
Human data( Rickettsia rickettsii) 
Dose CLINICAL SIGNS NOT CLINICAL SIGNS Total
13 2 4 6
126 6 1 7
1260 17 1 18

 

Goodness of fit and model selection
Model Deviance Δ Degrees 
of freedom		 χ20.95,1 
p-value		 χ20.95,m-k 
p-value
Exponential 13.5 13.2 2 3.84 
0.000277		 5.99 
0.00119
Beta Poisson 0.248 1 3.84 
0.618
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 6.75E-01 1.17E-01 2.44E-01 3.31E-01 1.21E+03 3.74E+03 4.98E+03
N50 2.36E+01 2.56E-02 3.35E+00 7.30E+00 6.41E+01 8.91E+01 1.28E+02

 

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

  • Saslaw, S. ., & Carlisle, H. N. (1966). Aerosol infection of monkeys with Rickettsia rickettsii. Bacteriological Reviews, 30, 3.