We generally recommend a single dose-response model, and we justify the decision in terms of specific criteria. This decision is somewhat subjective, since dose response datasets seldom meet all of these criteria. If all available models are unsatisfactory, we choose a single model to ‘recommend with reservations’. Our recommended model will seldom (if ever) be the best model for all applications. The user should carefully choose the model that is most appropriate for their particular problem. 

Criteria for Model Selection

We prefer dose-response models with the following criteria, in rough order of importance: 

  1. Statistically acceptable fit (fail to reject goodness of fit, p > 0.05)
  2. Human subjects, or animal models that mimic human pathophysiology well
  3. Infection as the response, rather than disease, symptoms, or death
  4. Exposure route similar/identical to the exposure route of natural infection
  5. Pathogen strain is similar to strains causing natural infection
  6. Pooled model using data from 2 or more experiments, provided the data sets are statistically similar (fail to reject that datasets are from the same distribution, p > 0.05)
  7. Low ID50/LD50 (to obtain a conservative risk estimate)
Agent Μodel Optimized parameters LD50/ID50 Host type Agent Strain Exposure Route # of Doses Dose Units Response Reference
Adenovirus
Experiments
exponential
k = 6.07E-01

1.14E+00 human type 4 inhalation 4 TCID50 infection Couch, R. B., et al. "Effect of route of inoculation on experimental respiratory viral disease in volunteers and evidence for airborne transmission." Bacteriological Reviews. 30 (1966): 3.
Bacillus anthracis
Experiments
exponential
k = 1.65E-05

4.2E+04 guinea pig Vollum inhalation 4 spores death June, R. C., W. W. Ferguson, and M. T. Worfel. "Experiments in feeding adult volunteers with Escherichia coli 55, B5, a coliform organism associated with infant diarrhea." American journal of hygiene. 57 (1953): 2.
Burkholderia mallei
Experiments
beta-Poisson a = 3.28E-01

N50 = 5.43E+03
5.43E+03 C57BL/6 mice and diabetic rat KHW,316c 10 CFU death Brett, Paul J., and Donald E. Woods. "Structural and immunological characterization of Burkholderia pseudomallei O-polysaccharide-flagellin protein conjugates." Infection and immunity. 64 (1996): 2824-2828.
Coxiella burnetii
Experiments
beta-Poisson a = 3.57E-01

N50 = 4.93E+08
4.93E+08 C57BL/1OScN mice phase I Ohio intraperitoneal 10 PFU death Williams, J. C., and J. L. Cantrell. "Biological and immunological properties of Coxiella burnetii vaccines in C57BL/10ScN endotoxin-nonresponder mice." Infection and Immunity. 35 (1982): 3.
Cryptosporidium hominis
Experiments
exponential
k = 5.72E-02

1.21E+01 human TAMU isolate oral 4 oocysts infection Messner, M. J., C. L. Chappell, and P. C. Okhuysen. "Risk Assessment for Cryptosporidium: A Hierarchical {B}ayesian Analysis of Human Dose Response Data." Water Research. 35 (2001): 16.
Cryptosporidium parvum
Experiments
beta-Poisson a = 1.01E-01

N50 = 3.41E+02
3.41E+02 human From an infected human oral 5 Cysts infection Rendtorff, R. C.. "The experimental transmission of human intestinal protozoan parasites. I. Endamoeba coli cysts given in capsules." American journal of hygiene. 59 (1954): 2.
Echovirus
Experiments
beta-Poisson a = 1.06E+00

N50 = 9.22E+02
9.22E+02 human strain 12 oral 4 PFU infection Schiff, G. M., et al. "Studies of echovirus-12 in volunteers: determination of minimal infectious dose and the effect of previous infection on infectious dose." The Journal of infectious diseases. 150 (1984): 6.
Enterovirus
Experiments
exponential
k = 3.74E-03

1.85E+02 pig porcine, PE7-05i oral 3 PFU infection CLIVER, DEAN O.. "Experimental infection by waterborne enteroviruses." Journal of Food Protection. 44 (1981): 861-865.
Escherichia coli
Experiments
beta-Poisson a = 1.55E-01

N50 = 2.11E+06
2.11E+06 human EIEC 1624 oral (in milk) 3 CFU positive stool isolation DuPont, H. L., et al. "Pathogenesis of Escherichia coli diarrhea." The New England journal of medicine. 285 (1971): 1.
Francisella tularensis
Experiments
exponential
k = 4.73E-02

1.46E+01 monkey SCHU S-4 inhalation 4 CFU death Quan, S. F., A. G. McManus, and H. von Fintel. "Infectivity of Tularemia Applied to Intact Skin and Ingested in Drinking Water." Science. 123 (1956): 942-943.
Giardia duodenalis
Experiments
exponential
k = 1.99E-02

3.48E+01 human From an infected human oral 8 Cysts infection Rendtorff, R. C.. "The experimental transmission of human intestinal protozoan parasites. II. Giardia lamblia cysts given in capsules." American journal of hygiene. 59 (1954): 2.
Influenza
Experiments
beta-Poisson a = 5.81E-01

N50 = 9.45E+05
9.45E+05 human H1N1,A/California/10/78 attenuated strain,H3N2,A/Washington/897/80 attenuated strain intranasal 9 TCID50 infection Murphy, B. R., et al. "Dose Response of Cold-Adapted, Reassortant Influenza A/California/10/78 Virus (H1N1) in Adult Volunteers." Journal of Infectious Diseases. 149 (1984): 5.
Lassa virus
Experiments
exponential
k = 2.95E+00

2.35E-01 guinea pig Josiah strain subcutaneous 6 PFU death Jahrling, P. B., et al. "Pathogenesis of Lassa virus infection in guinea pigs." Infection and Immunity. 37 (1982): 2.
Legionella pneumophila
Experiments
exponential
k = 5.99E-02

1.16E+01 guinea pig Philadelphia 1 inhalation 4 CFU infection Fitzgeorge, R. B., et al. "Aerosol infection of animals with strains of Legionella pneumophila of different virulence: comparison with intraperitoneal and intranasal routes of infection." Epidemiology & Infection. 90 (1983).
Mycobacterium avium
Experiments
exponential
k = 6.93E-04

1000 deer sub sp. Paratuberculosis Bovine oral 3 CFU infection Nisbet, D. I., N. J. Gilmour, and J. G. Brotherston. "Quantitative studies of Mycobacterium johnei in tissues of sheep. III. Intestinal histopathology." Journal of comparative pathology. 72 (1962): 80.
Naegleria fowleri
Experiments
exponential
k = 3.42E-07

2.03E+06 mice LEE strain intravenous 7 no of trophozoites death Adams, AC, DT John, and SG Bradley. "Modification of resistance of mice to Naegleria fowleri infections." Infection and immunity. 13 (1976): 1387-1391.
Poliovirus
Experiments
exponential
k = 4.91E-01

1.41E+00 human type 1,attenuated oral (capsule) 3 PD50 (mouse paralytic doses) alimentary infection Koprowski, H.. "Immunization against Poliomyelitis with Living Attenuated Virus." The American Journal of Tropical Medicine and Hygiene. 5 (1956): 3.
Prion
Experiments
beta-Poisson a = 1.76E+00

N50 = 1.04E+05
1.04E+05 hamsters scrapie strain 263k oral 5 LD50 i.c. death Jacquemot, C., et al. "High Incidence of Scrapie Induced by Repeated Injections of Subinfectious Prion Doses." Journal of Virology. 79 (2005): 14.
Pseudomonas aeruginosa
Experiments
beta-Poisson a = 1.9E-01

N50 = 1.85E+04
1.85E+04 white rabbit contact lens 10 CFU corneal ulceration Lawin-Brüssel, C. A., et al. "Effect of Pseudomonas aeruginosa concentration in experimental contact lens-related microbial keratitis." Cornea. 12 (1993): 1.
Pseudomonas aeruginosa
Experiments
exponential
k = 1.05E-04

6.61E+03 Swiss webster mice (5day old) ATCC 19660 injected in eyelids 12 CFU death Hazlett, L. D., D. D. Rosen, and R. S. Berk. "Age-Related Susceptibility to Pseudomonas aeruginosa Ocular Infections in Mice." Infection and Immunity. 20 (1978): 1.
Pseudomonas aeruginosa
Experiments
beta-Poisson a = 1.9E-01

N50 = 1.85E+04
1.85E+04 white rabbit contact lens 10 CFU corneal ulceration Lawin-Brüssel, C. A., et al. "Effect of Pseudomonas aeruginosa concentration in experimental contact lens-related microbial keratitis." Cornea. 12 (1993): 1.
Pseudomonas aeruginosa
Experiments
exponential
k = 1.05E-04

6.61E+03 Swiss webster mice (5day old) ATCC 19660 injected in eyelids 12 CFU death Hazlett, L. D., D. D. Rosen, and R. S. Berk. "Age-Related Susceptibility to Pseudomonas aeruginosa Ocular Infections in Mice." Infection and Immunity. 20 (1978): 1.
Rhinovirus
Experiments
beta-Poisson a = 2.21E-01

N50 = 1.81E+00
1.81E+00 human type 39 intranasal 6 TCID50 infection Hendley, J. O., W. P. Edmondson, and J. M. Gwaltney. "Relation between Naturally Acquired Immunity and Infectivity of Two Rhinoviruses in Volunteers." Journal of Infectious Diseases. 125 (1972): 3.
Rickettsia rickettsi
Experiments
beta-Poisson a = 7.77E-01

N50 = 2.13E+01
2.13E+01 pooled R1 and Sheila Smith 27 CFU morbidity Saslaw, S., and H. N. Carlisle. "Aerosol infection of monkeys with Rickettsia rickettsii." Bacteriological Reviews. 30 (1966): 3.
Rotavirus
Experiments
beta-Poisson a = 2.53E-0.2

N50 = 6.17E+00
6.17E+00 human oral 8 FFU Ward, R. L., et al. "Human Rotavirus Studies in Volunteers: Determination of Infectious Dose and Serological Response to Infection." Journal of Infectious Diseases. 154 (1986): 5.
Salmonella anatum
Experiments
beta-Poisson a = 3.18E-01

N50 = 3.71E+04
3.71E+04 human strain I oral (with eggnog) 16 CFU positive stool culture McCullough, Norman B., and Wesley C Elsele. "Experimental human salmonellosis: I. Pathogenicity of strains of Salmonella meleagridis and Salmonella anatum obtained from spray-dried whole egg." The Journal of infectious diseases (1951): 278-289.
Salmonella meleagridis
Experiments
beta-Poisson a = 3.89E-01

N50 = 1.68E+04
1.68E+04 human strain I oral (with eggnog) 11 CFU infection McCullough, N. B., and C. W. Elsele. "Experimental Human Salmonellosis: I." Pathogenicity of Strains of Salmonella meleagridis and Salmonella anatum Obtained from Spray-Dried Whole Egg. 88 (1951): 3.
Salmonella newport
Experiments
exponential
k = 3.97E-06

1.74E+05 human *Salmonella newport* oral 3 CFU infection McCullough, N. B., and C. W. Elsele. "Experimental Human Salmonellosis: I." Pathogenicity of Strains of Salmonella meleagridis and Salmonella anatum Obtained from Spray-Dried Whole Egg. 88 (1951): 3.
Salmonella nontyphoid
Experiments
beta-Poisson a = 2.1E-01

N50 = 4.98E+01
4.98E+01 mice strain 216 and 219 intraperitoneal 10 CFU death Meynell, G. G., and E. W. Meynell. "The growth of micro-organisms in vivo with particular reference to the relation between dose and latent period." Epidemiology & Infection. 56 (1958).
Salmonella typhi
Experiments
beta-Poisson a = 1.75E-01

N50 = 1.11E+06
1.11E+06 human Quailes oral (in milk) 8 CFU disease Hornick, R. B. al.. "Study of induced typhoid fever in man. I. Evaluation of vaccine effectiveness." Transactions of the Association of American Physicians. 79 (1966): 361-367.
SARS
Experiments
exponential
k = 2.46E-03

2.82E+02 mice hACE-2 and A/J rSARS-CoV intranasal 0 PFU death
Shigella flexneri
Experiments
beta-Poisson a = 2.65E-01

N50 = 1.48E+03
1.48E+03 human 2a (strain 2457T) oral (in milk) 4 CFU positive stool isolation Altboum, Z., et al. "Postexposure Prophylaxis against Anthrax: Evaluation of Various Treatment Regimens in Intranasally Infected Guinea Pigs." Infection and Immunity. 70 (2002): 11.
Staphylococcus aureus
Experiments
exponential
k = 7.64E-08

9.08E+06 human subcutaneous 6 CFU/cm2 infection Lawin-Brüssel, C. A., et al. "Effect of Pseudomonas aeruginosa concentration in experimental contact lens-related microbial keratitis." Cornea. 12 (1993): 1.
Vibrio cholerae
Experiments
beta-Poisson a = 2.50E-01

N50 = 2.43E+02
2.43E+02 human Inaba 569B oral (with NaHCO3) 6 CFU infection Diringer, H., J. Roehmel, and M. Beekes. "Effect of repeated oral infection of hamsters with scrapie." Journal of General Virology. 79 (1998): 3.
Yersinia pestis
Experiments
exponential
k = 1.63E-03

4.26E+02 mice CO92 intranasal 4 CFU death Lathem, W. W., et al. "Progression of primary pneumonic plague: A mouse model of infection, pathology, and bacterial transcriptional activity." Proceedings of the National Academy of Sciences of the United States of America. 102 (2005): 17786-17791.