Submitted by admin on

Experiment ID
242, 243
Pathogen
Legionella pneumophila
Agent Strain
strain 74/81
Contains Preferred Model
No
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
death
Host type
mice
# of Doses
9.00
Dose Units
CFU
Μodel
exponential
k
4.99E-05
LD50/ID50
1.39E+04
Description
Dose response data
Dose Dead Survived Total
200 0 10 10
4000 1 9 10
1E+04 1 4 5
15000 0 3 3
2E+04 5 2 7
5E+04 12 0 12
5E+04 3 0 3
1E+05 5 0 5
4E+05 16 0 16

 

Goodness of fit and model selection
Model Deviance Δ Degrees 
of freedom		 χ20.95,1 
p-value 		χ20.95,m-k 
p-value
Exponential 8.92 -0.000282 8 3.84 
1 		15.5 
0.349
Beta Poisson 8.92 7 14.1 
0.258
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 4.99E-05 3.55E-05 3.87E-05 3.95E-05 6.48E-05 6.76E-05 7.46E-05
ID50/LD50/ETC* 1.39E+04 9.29E+03 1.03E+04 1.07E+04 1.75E+04 1.79E+04 1.95E+04
*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

  • 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.
  • Breiman, R. F., & Horwitz, M. A. (1987). Guinea pigs sublethally infected with aerosolized Legionella pneumophila develop humoral and cell-mediated immune responses and are protected against lethal aerosol challenge. A model for studying host defense against lung infections caused by intracellul. The Journal of Experimental Medicine, 165, 3.