Term
|
Definition
| -ability of an infectious dz to spread within a susceptible population by direct or indirect contact |
|
|
Term
| True or False: The term "contagious" excludes vector transmission. |
|
Definition
|
|
Term
|
Definition
| -disease can be induced by transmission or inoculation of agent/organism |
|
|
Term
|
Definition
| -ability to cause infection in a susceptibile host, measured by the min number of infectious particles required to establish infection |
|
|
Term
| Definition: Pathogenicity |
|
Definition
-ability of agent to induce disease
-reflected by the Attack Rate: proportin of individuals clinially affected after being exposed |
|
|
Term
|
Definition
| -abilkity to induce severe disease or death |
|
|
Term
| Definition: Immunogenicity |
|
Definition
| -ability to induce immune response in host that can be protective in case of future exposure |
|
|
Term
| In what ways does an infectious agent evolve to maintain their existence? |
|
Definition
| -prolific shedding, mile to moderate virulence, minimize antigenicity/antigenic variation, survivie in environment, etc |
|
|
Term
| Give three examples of vertical transmission. |
|
Definition
-trans-ovarial
-in utero
-colostral |
|
|
Term
|
Definition
| -presence of agent that shouldn't be there at all or oan agent in an incorrect place |
|
|
Term
|
Definition
|
|
Term
|
Definition
| -signs not apparent without special test/axamination |
|
|
Term
|
Definition
| -derangement of fucntion is apparent to a reasonably astutue observer |
|
|
Term
|
Definition
| -presence of agent anywhere in the body |
|
|
Term
| Describe the "Iceberg Concept" of Disease. |
|
Definition
| -the economic cost of subclinical disease usually exceeds that of the clinical disease b/c subclinical cases are more numerous than clinical cases |
|
|
Term
| What are the 4 primary misconceptions due to not understanding the iceberg concept? |
|
Definition
1) consider only clinically ill animas: as warranting attention and as shedding agent
2) interpreting absence of clinical cases as absence of disease/agent
3) interpreting presence of infection as indicating agents is the cause of the disease
4) interpreting decline of clinical cases over time as evidence that veterinary or managment interventions were effective |
|
|
Term
| Disease results from interactions b/n what factors? |
|
Definition
-agent: toxic or infectious
-host
-environment |
|
|
Term
| What is the Epidemiologic Triad? |
|
Definition
| -The relationship b/n agent factors, environmental factors, and host factors (intrinsic and extrinsic) |
|
|
Term
| What are some examples of agent factors? |
|
Definition
-sode
-environmental hardiness
-virulence
-infectivity
-toxicity |
|
|
Term
| What are some examples of host factors? |
|
Definition
-immune factors: innate vs acquired (passive inneonates, previous exposure, vx status and response)
-Non-immune factors: age, gender, behavior, pdn status, repro status
-Intrinsic: age, genetics
-Extrinsic: vx status, intact or neutered |
|
|
Term
| What are some examples of environmental factors? |
|
Definition
-animal stocking density
-animal movement b/n groups
-housing
-environmental conditions
-nutrition |
|
|
Term
|
Definition
| -the first case identified oor the original introducer of the disease to the population |
|
|
Term
| Definition Secondary cases |
|
Definition
| -"new" infections directly attributable to contact or interaction with a known infected individual |
|
|
Term
| Definition: Basic reproduction number (R0) |
|
Definition
| -mean number of secondary cases a typical case will cause in population WITH NO IMMUNITY IN ABSENCE OF INTERVENTIONS to control infection |
|
|
Term
What is R0? What is the significance of the following values:
a) R0 < 1
b) R0 = 1
c) R0 > 1 |
|
Definition
-the basic repro number
a) disease dies out
b) disease is endemic
c) disease spreads |
|
|
Term
| R0 is determine by a combination of what? |
|
Definition
-infectivity of agent
-likelihood os suceptbile house encountering agent: number of susceptible animals, proximity of susceptbile animals to sources of infection (stocking density), amount and duration of shedding, stability of agent in environment |
|
|
Term
|
Definition
| -the proportion of population not susceptible |
|
|
Term
| Transmission requires what type of host? Typically what percentage of the population? |
|
Definition
-susceptible
-typically at elast 10-20% of population |
|
|
Term
| OUtbreaks of rabies in dogs will not propogate if >___% of dogs are immunized. |
|
Definition
|
|
Term
| True or False: Vaccination and immunization are synonymous. |
|
Definition
|
|
