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Experiment ID
241
Pathogen
Legionella pneumophila
Agent Strain
Philadelphia 1
Contains Preferred Model
Yes
Reference
Fitzgeorge, R. B., Baskerville, A. ., Broster, M. ., Hambleton, P. ., & Dennis, P. J. (1983). Aerosol infection of animals with strains of Legionella pneumophila of different virulence: comparison with intraperitoneal and intranasal routes of infection. Epidemiology & Infection, 90.
Exposure Route
inhalation
Response
infection
Host type
guinea pig
# of Doses
4.00
Dose Units
CFU
Μodel
exponential
k
5.99E-02
LD50/ID50
1.16E+01
Description
Guinea pigs/ Philadelphia 1 strain data 
Dose Infected Non-infected Total
1 0 4 4
5 4 10 14
50 17 1 18
100 8 0 8

 

Goodness of fit and model selection
Model Deviance Δ Degrees 
of freedom		 χ20.95,1 
p-value 		χ20.95,m-k 
p-value
Exponential 0.582 0.000479 3 3.84 
0.983 		7.81 
0.9
Beta Poisson 0.582 2 5.99 
0.748
Exponential is preferred to beta-Poisson; cannot reject good fit for exponential.

 

Optimized k parameter for the exponential model, from 10000 bootstrap iterations
Parameter MLE estimate Percentiles
0.5% 2.5% 5% 95% 97.5% 99.5%
k 5.99E-02 3.26E-02 3.90E-02 4.18E-02 1.11E-01 1.31E-01 1.57E-01
ID50/LD50/ETC* 1.16E+01 4.42E+00 5.28E+00 6.25E+00 1.66E+01 1.78E+01 2.13E+01
*Not a parameter of the exponential model; however, it facilitates comparison with other models.

 

Parameter histogram for exponential model (uncertainty of the parameter)

Exponential model plot, with confidence bounds around optimized model

References

  • Muller, D. ., Edwards, M. L., & Smith, D. W. (1983). Changes in Iron and Transferrin Levels and Body Temperature in Experimental Airborne Legionellosis. The Journal of Infectious Diseases, 147, 2. https://doi.org/https://doi.org/10.1093/infdis/147.2.302