Term
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Definition
| the study of how disease is distributed in populations and the factors that influence or determine the distribution |
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Definition
protecting the non-infected
Ex:vaccination, biosecurity, closed herd |
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Definition
detecting pre-clinical dsease
Ex:reducing severity, complications, preventing spread |
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Definition
reducing the impact of clinical disease
Ex: treatment, therapy, rehab |
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Definition
retrospective study on outbreak of Cholera in London
lesson is that a disease outbreak can be stopped by understanding disease patterns, witho specific knowledge of the causative agent(s) |
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Definition
| the usual (habitual) occurrence of a disease within a given area |
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Definition
| separate or scattered disease incidents occurring at a low frequency |
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Definition
| more disease than expected for a given time and place |
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Definition
| epidemic affecting several continents |
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Definition
pre-clinical harborer of disease
many organism being shed |
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Term
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Definition
| an animal which continue to harbor and shed organisms for a variable period of time following recovery |
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Term
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Definition
| subclinical but may shed organisms for variable periods |
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Term
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Definition
| these animals shed organisms for long periods of time continuously or intermittently |
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Term
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Definition
| any animal (including humans), arthropod, plant, soil, or inanimate matter in which an infectious agent normally lives and multiplies or on which it depends primarily for survival and reproduces in such a way that it can be transmitted to a susceptible host |
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Term
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Definition
| a localized reservoir that persists over a very long time period |
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Term
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Definition
| an object, substance, or non-receptive living being serving as an intermediary in transmitting a pathogen from the organism hosting it to a receptive host |
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Term
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Definition
| a living creature which, because of its ecological relationship to others, acquires a pathogen from one living host and transmits it to another |
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Term
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Definition
| an object or material that is not in itself harmful, but on which pathogens may be conveyed |
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Term
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Definition
| the time between exposure to the pathogen and the onset of clinical signs |
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Definition
| an in-apparent infection that has the potential to develop signs of disease. The triggering mechanism may be an altered host response |
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Term
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Definition
| the animal, person, or object from which an infectious agent passes immediately to the host (not necessarily synonymous with reservoir). |
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Term
| Intrinsic Host Factors (6) |
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Definition
Species
Age
Breed
Gender
Physiological State
Disease history |
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Term
| Extrinsic Host Factors (2) |
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Definition
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Term
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Definition
Infectivitiy
Infectiousness
Pathogenicity
Virulence
Host Range
Viability |
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Term
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Definition
Temperature, barometric pressure, radiation, oxygen concentration, precipitation, humdity, wind, etc.
Macrometeorology
Micrometeorology
Presence of reservoirs, vectors, herd immunity |
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Term
| Direct Aerosol Transmission |
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Definition
| Expiratory droplets: produced by cough, sneeze, or snort (>10 microns, short airborne life, 3 ft. projection, 40,000 per sneeze or cough, most evaporate before hitting the ground. Deposited into respiratory tree according to size. |
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Term
| Indirect Aerosol Transmission |
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Definition
| Droplet nuclei: truly airborne. Evaporated remains of expiratory droplets and other fluids. Smaller than 5 microns. Settle very slowly (permanently suspended). Inhaled into alveoli. Ten times more infectious than expiratory droplets. |
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Term
| Recipe for Disease Spread |
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Definition
A causative agent capable of infecting the host
A reservoir or source of the agent
A mode of escape from the reservoir or immediate source
A mode of transmission to the new potential host
A mode of entry into the new host
A susceptible host |
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Term
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Definition
| An abnormality of structure and/or function that interferes with the well-being of the individual animal. Also any condition resulting in suboptimal production, growth or efficiency |
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Term
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Definition
Outward manifestation of disease (signs or symptoms)
requires tertiary prevention |
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Term
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Definition
Not yet clinically apparent, but destined to be
requires secondary prevention |
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Term
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Definition
Not clinical and not destined to be
requires primary prevention |
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Term
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Definition
Susceptible animals are a relatively well protected in a herd by reducing the probability that they will come in contact with a “shedding” animal.
If there is continuous introduction of susceptible animals adequate herd immunity will never be achieved.
The frequency of contact among susceptibles is the most critical factor. |
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Term
| Outbreak Investigation Steps |
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Definition
1.Establish that an epidemic exists
2.Verify the diagnosis
3.Survey known cases
4.Formulate tentative hypotheses
5.Plan and conduct detailed epi investigation
6.Assemble and analyze data
7.Test hypotheses
8.Formulate conclusions
9.Implement controls
10.Prepare report |
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Term
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Definition
| the first recognized case of a disease in an outbreak |
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Definition
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Term
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Definition
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Definition
| Common Source with Intermittent Exposure |
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Term
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Definition
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Term
| Minimum incubation period |
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Definition
| the time between exposure and the first set of cases |
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Term
| Average incubation period |
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Definition
| the time between exposure and the first peak of cases |
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Term
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Definition
| – Determine exposures among each individual in the entire population at risk. Then determine whether or not disease occurred in each individual |
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Term
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Definition
| – Identify a group of individuals from the population at risk with the disease and find out about their exposures. Then find a similar group of individuals from the same population at risk without the disease and find out about their exposures |
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Term
| Retrospective Cohort necessities |
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Definition
Members of the cohort are easily identifiable
Members of the cohort are easily accessible
Exposure is rare
There may be multiple diseases involved |
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Term
| Case-Control Study necessities |
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Definition
Used when identifying the entire cohort would be too costly or time consuming
The illness is rare |
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Term
| Attack Rate in the Exposed |
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Definition
Attack rate in the exposed = A / (A + B)
= number who are BOTH exposed and diseased divided by the total number exposed |
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Term
| Attack Rate in the Unexposed |
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Definition
Attack rate in the unexposed = C / (C + D)
= number who are diseased and NOT exposed divided by the total number NOT exposed |
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Term
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Definition
| the ease with which the agent is transmitted from one host to another |
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Term
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Definition
| the degree of pathogenicity |
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Term
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Definition
| the ability to produce disease |
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Term
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Definition
| resistance of an at risk population to an attack by a disease to which a large proportion of the members of the group are immune |
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