Term
| percentage of worldwide deaths due to ID's |
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Definition
| 1/3 (including 63% of deaths in Africa) |
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Term
| Factors influencing emergence |
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Definition
1. Population Growth/Zoonotic interface
2. Change in underlying health of community (concomitant
infection, starvation, etc.)
3. Speed of travel
4. Geographic alterations (homes, dams, forests, etc.)
5. Climate changes
6. War and social disruption
7. Changing living patterns
8. Medical advances |
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Term
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Definition
| average number of secondary cases produced in a n infectious host when exposed to susceptible population |
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Term
| What reproductive number guarentees spread |
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Definition
- R0 greater than R
- R = average number of secondary cases in a mixed community
- R0 is always greater than 1
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Term
| What can influence secondary attack rate |
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Definition
- level of susceptibility of population
- level of social interaction amongst susceptibles
- interaction of those ill and those susceptible
- result- widely varying R levels for same disease process
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Term
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Definition
| interval from infection to onset of clinical illness |
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Term
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Definition
| interval from infection to time of maximal infectivity for others |
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Term
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Definition
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Term
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Definition
| ability of agent to produce clinically apparent disease in host |
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Term
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Definition
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Term
| What determines whether a person will experience an infectious disease |
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Definition
l1) Exposure to the infectious agent
l2) Susceptibility to infection (underlying health status)
l3) Specific Immunity to particular infectious agent |
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Term
| factors determining exposure to infectious agent |
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Definition
lWHO YOU ARE -
–Gender/Ethnicity
–Cultural Factors
lWHAT YOU DO –
–Occupation
–Behavioral Patterns
–Hospitalization/Institutionalization
–Sexual activity
–Travel
–Hygienic Patterns |
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Term
| factors affecting occurence and severity of disease |
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Definition
lWHAT’S YOUR HEALTH -
–Immunity
–Immune Status
–Nutritional Status
–Co-existing infection
lHOW ARE YOU EXPOSED–
–Portal of Entry
–Infectious Dose |
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Term
| properties of infectious agent that affect host response |
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Definition
–Morphology of the Infectious Agent
–Growth Requirements…………
–Toxin Production………….
–Antibiotic Resistance………..
–Pathogenic Mechanism………. |
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Term
| Factors in classifying infectious agent |
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Definition
lBy Microbiologic properties
lBy Mode of transmission
lBy Pathogenic mechanism
lBy Reservoir of organism |
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Term
| classifications of modes of transmission |
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Definition
lBy generation: “Horizontal” or “Vertical” (perinatal)
lBy contact: “Direct” or “Indirect”
lBy vehicle: “Vector-borne”, “Food/water-borne”, “airborne”, “Device-borne”
lBy source: “Point source”, “Continuing source”, “Person-to-person” |
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Term
| Why classify infectious agents by mode of transmission |
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Definition
lHelps in understanding etiology of clinical syndrome
lAllows public health intervention before identification |
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Term
| Essential elements of epidemic to develop |
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Definition
lAppropriate” infectious agent
Example: Salmonella
l“Sufficient” number of susceptibles
Example: Measles
l“Mechanism” that allows for rapid spread
Example: Legionellosis |
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Term
| circumstances that increase likelihood of epidemic |
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Definition
lChange in dose of agent
lChange in virulence of agent
lChange in mode of transmission
lChange in susceptibility of host
lChange in cultural/behavioral aspect of host |
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Term
| factors making person to person transmission likely |
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Definition
-
Individual: Prior exposure to agent (immunity); immune status; general health status
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Social: “Closed” community; behavioral issues; cultural patterns
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Environment: Climate change; use of intermediate vehicle for transmission (water, food, etc.)
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Term
| features of the infectious agent that make person to person transmission more likely |
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Definition
lHigh infectivity of organism
Example: Measles
l“Short” generation time (as compared to incubation period)
Example: Varicella
lAbility of organism to exist in “carrier” state
Example: Hepatitis B |
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Term
| types of carrier states for infectious agents |
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Definition
Inapparent - Polio, meningococcus
Incubatory - Measles, chicken pox
Convalescent - Salmonella, diphtheria
Chronic - Typhoid, HIV, Hepatitis B |
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Term
| equation for vaccine efficacy |
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Definition
ARunvaccinated - ARvaccinated
ARunvaccinated
AR = attack rate |
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Term
| equation for vaccine coverage |
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Definition
Nvaccinated
Nvaccinated + Nunvaccinted |
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Term
| Limit spread of infectious agents |
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Definition
Environment: Sanitation, water purification
Social: Behavioral change, barrier protection
Host: Prophylactic medications, immunization |
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Term
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Definition
| Ability of agent to produce immune response in a host |
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Term
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Definition
| Ability of agent to invade and multiply in host |
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Term
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Definition
- Ability of agent to produce severe disease in a host
- LD50- number of organisms needed to cause death in 50% of infected host
- ID50- number of organisms needed to cause infection in 50% of hosts
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