General Overview
Echoviruses, a member of the enterovirus genus, is a type of RNA virus that were shown to be a frequent cause of simple febrile illnesses and aseptic meningitis. Most infected persons experience no symptoms or have selflimited disease. Deaths and other adverse consequences are rare and limited to patients with severe echovirus encephalitis or to persons with B celldeficiency syndromes who develop persistent infection (Modlin 1986[1]).
Human echoviral infection occurs via fecaloral transmission. Infants are particularly susceptible to echovirus infection. Both vertical transmission from an infected mother and nosocomial transmission via hospital personnel appear to be important sources of infection for the neonate. Severe disease and death may follow the infection that occurs with the first 1014 days of life (Modlin 1986[1]).
Summary Data
Schiff et al. (1984) challenged human volunteers lacking detectable serum antibody with echovirus12 in chilled drinking water. The virus used in the study was originally recovered from a child with a clinical diagnosis of erythema infectiousum (fifth disease). The infection with echovirus12 among volunteers was determined by intestinal shedding of virus and seroconversion.
Summary
The limited numbers of subjects under dose 33000 and 330000 might have contributed to their deviations from other dose groups and the unsuccessful fitting. By excluding these two outliner groups, significantly better fit was achieved (The reduction of deviance is substantially greater than the chisquare value at the degree of freedom of 2)
References
 Perinatal Echovirus Infection: Insights from a Literature Review of 61 Cases of SeriousInfection and 16 Outbreaks in Nurseries, , Reviews of Infectious Diseases, Volume 8, p.918926, (1986)
ID  # of Doses  Agent Strain  Dose Units  Host type  Μodel  Optimized parameters  Response type  Reference 

112  6  strain 12  PFU  human  betaPoisson 
a = 3.74E01 LD_{50}/ID_{50} = 1.01E+03 N_{50} = 1.01E+03 
infection  Pathogenesis of experimental Coxsackie virus infection." Archive of Virology. 7 (1963): 6166.  "
256 (excluding the outliers of exp 112)  4  strain 12  PFU  human  betaPoisson 
a = 1.06E+00 LD_{50}/ID_{50} = 9.22E+02 N_{50} = 9.22E+02 
infection  Studies of echovirus12 in volunteers: determination of minimal infectious dose and the effect of previous infection on infectious dose." The Journal of infectious diseases. 150 (1984): 6.  "
LD_{50}/ID_{50} = 1.01E+03
N_{50} = 1.01E+03



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
 Studies of echovirus12 in volunteers: determination of minimal infectious dose and the effect of previous infection on infectious dose, , The Journal of infectious diseases, Volume 150, p.6, (1984)
LD_{50}/ID_{50} = 9.22E+02
N_{50} = 9.22E+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
 Studies of echovirus12 in volunteers: determination of minimal infectious dose and the effect of previous infection on infectious dose, , The Journal of infectious diseases, Volume 150, p.6, (1984)