Glossary

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More terms (with definitions concise enough to fit in tooltips auto-generated by the Lingo extension throughout QMRAwiki) are to be added below, in alphabetical order. As the glossary gets longer we may break it up into sections by first letter. Generally, each entry should be singular and start with a lower case letter (except for acronyms). Start each definition with a capital letter, and end with a period. If you need a particular variant of a word to have a tooltip somewhere in QMRAwiki (e.g, capitalized, or plural, or alternate spelling), add the variant to the appropriate definition.

advanced dose response model
A more detailed dose response model than the exponential model or beta-Poisson model. It might incorporate age, incubation period, multiple dosing, or other aspects.
agent
agents
An organism that can infect host organisms and reproduce within them, possibly causing disease.
alpha
α
A parameter used in the beta-Poisson dose response model.
bacteriophage
bacteriophages
phage
phages
A virus that infects bacteria. In research, often used as surrogates for more dangerous viruses.
beta
β
A parameter used in an alternative formulation of the beta-Poisson dose response model, instead of N₅₀.
beta-Poisson
beta-Poisson model
beta-Poisson dose response model
A dose response model with 2 parameters (α and N₅₀; alternatively, α and β). If α is very large, this model reduces to the exponential model.
bootstrap
bootstrapping
A technique for assessing likely variability in a dataset by repeatedly resampling with replacement from that dataset.
CAMRA
Center for Advancing Microbial Risk Assessment (the organization that originated QMRAwiki).
CFR
case fatality ratio
Case Fatality Ratio
The case fatality ratio is the proportion of infections (or illnesses) that end in death. It can easily be biased upward if many infections are mild or asymptomatic (and therefore unreported).
CDC
United States Centers for Disease Control and Prevention (cdc.gov).
CFU
Colony-forming units, a common unit for quantifying bacteria (since a colony on a petri dish is assumed to arise from ~1 bacterium).
cutaneous
Pertaining to the skin.
dose response
The relationship describing the probability of a response (e.g., infection, disease, death) given a dose of an agent.
dose response model
An equation describing the probability of a response given a dose of an agent. Two main types are the exponential and beta-Poisson models.
EHEC
Enterohemorrhagic Escherichia coli.
EITS
Environmental Infection Transmission System model.
EPA
USEPA
United States Environmental Protection Agency (epa.gov).
endemic
endemicity
Pertains to a relatively stable level of disease in a population.
epidemic
epidemics
An unusually large occurrence of an infection or a disease within a population.
experiment ID
Experiment ID
experiment identifier
experiment serial number
Experiment serial number
An arbitrarily assigned number designating a unique dose response experiment ('feeding study').
exponential model
exponential dose response model
A dose response model with a single parameter (k). It is a special case of the beta-Poisson model.
feeding study
feeding studies
Feeding studies
feeding experiment
In a 'feeding study', hosts are given differing doses of an agent, and responses from the hosts are measured. Feeding studies supply the data for fitting dose response models. Doses might not be technically 'fed' to the host; they could be injected, inhaled, etc.
hazard
A particular infectious agent and its adverse consequences.
hazard ID
Hazard ID
hazard identification
Hazard identification is the first step in a QMRA. It comprises general information about the agent and its adverse consequences.
host
hosts
An organism that is parasitized by infectious agents.
ID
The infectious dose. Commonly used as ID₅₀, the dose required to infect 50% of the hosts.
incubation period
The time between exposure to an agent and development of disease.
k
The single parameter for the exponential dose response model (corresponding to the probability of a single agent surviving to cause infection).
latent period
The time between exposure to an agent and development of infectiousness.
LD
The lethal dose. Commonly used as LD₅₀, the dose required to kill 50% of the hosts.
morbidity ratio
The probability of symptoms or disease, given infection by a particular pathogen in a particular population of hosts.
N
N₅₀ is the dose that gives a defined response in 50% of the hosts (see ID₅₀ or LD₅₀). It is a parameter in the beta-Poisson dose response model.
outbreak
outbreaks
A small epidemic.
PCR
polymerase chain reaction
The polymerase chain reaction is a rapid and sensitive method to amplify and detect DNA (from living or inactivated microorganisms).
PFU
Plaque-forming units, a common metric to quantify agents (usually viruses) by empty spots formed on a lawn of cells.
prion
prions
An infectious agent that consists only of protein; it has no nucleic acid component.
PSDS
Pathogen Safety Data Sheet, inspired by the Materials Safety Data Sheet (MSDS) for hazardous chemicals.
QMRA
Quantitative Microbial Risk Assessment.
qPCR
Quantitative polymerase chain reaction. A relatively new technique for quantifying the number of copies of a DNA sequence (possibly related to number of organisms) present in a sample. PCR methods do not distinguish between living and inactivated organisms.
risk communication
The process of explaining and promulgating risk information, usually to inform the general public.
response
responses
A binary outcome measured in a dose response experiment, for example: died/survived, infected/not, diseased/not, etc.
spore
spores
An extremely durable dormant stage of an organism (usually a bacterium).
TCID
tissue culture infectious dose
The minimum dose necessary to infect cells in culture. Sometimes used to measure virus infectivity.
zoonosis
zoonotic
A disease that primarily affects nonhuman animals but can sometimes infect humans.