Chapter 15: Epidemiology Flashcards
Epidemiology
Study factors involved in the spread of disease, looks at relationships among the host, microbe and environment
Etiology
the cause of disease
Epidemiologists
Have a dangerous job because they need to figure out where organisms are found (they sometimes have to go to dangerous places, such as war zones)
Incidence
The first time there is an infection notices, reported on weekly basis, strictly the number of NEW cases within a set population
Prevalence
How many people are infected with organism within a population at a given time, it is the TOTAL number of people
Morbidity rate
The number of individuals affected by disease
Mortality rate
The number of deaths due to disease
Endemic
Disease agent always present (CE)
Epidemic
Higher incidence number than normal that is spreading through a community (WEE)
Pandemic
Worldwide epidemic, spreading through the world rather than community
Sporadic Disease
Occurs in random and unpredictable manner involving several isolated cases that pose no great threat to the population as a whole (EEE)
Sources of infection: common source outbreak
Food poisoning, similar group of people that have something in common and they all get sick
Sources of infection: propagated epidemic
Common cold, spreads continuously, direct person to person contact “horizontal transmission”
Descriptive study
Epidemiology studies concerned with physical aspects of existing disease and disease spread
Index case
The first case of the disease to be identified
Analytical study
Cause and effect relationship with epidemiology study, can be retrospective or prospective
Retrospective study
takes into consideration things that happened before that happened before the incident
Prospective
considers factors that occur as an epidemic spreads, Ex: what children got sick, what age, their gender and living conditions
Experimental
Checking to see if certain experiments work or not against different diseases, trying to prove something
Placebo used in Experimental study
Non-medical substance that has no effect on the recipient but the recipient believes in the treatment
Reservoirs
Sites in which organisms can persist and maintain their ability to infect are essential for human infections to occur
Carriers:
carriers of infection with no apparent infection symptoms
Subclinical or inapparent infections
Has signs that are too milk to be recognized by special tests
Animal carriers
Zoonoses, hard to eliminate this reservoir because how do you get rid of it in an animal
Non living reservoirs
Soil, Water, Food
Communicable disease
If they can be transmitted during the incubation period and during recovery of the disease
Chronic carrier
Is a reservoir of infection for a long time after he or she has recovered from a disease
Intermittent carriers
periodically release infectious organisms
Vertical transmission
pathogens are passed from parent to offspring in egg across placenta
Portals of entry
Disease organisms can enter us through any openings in the body
Portals of exit
Diseases exit our body through any bodily fluids (including mothers milk, skin cells, fecal material)
Direct contact
Person comes in contact with the human carrying disease (Ex: herpes, rabies, Staph, warts, syphilis)
Indirect contact
Occurs through fomites (Ex: tetanus; nail is just a tool that breaks skin so that organisms in the soil can enter body) (Common cold, enterovirus, ringworm)
Contact through Droplets
Common cold, influenza, measles, Q fever
Droplet nuclei
Consists of dries mucus which protects microorganisms embedded in it
Vector
(1) there is something like an insect that is the source of infectious agent, transmits disease to human (2) Mechanical or Biological
Mechanical vector
An insect picks up disease microorganism on its body, flies on to something such as a sandwich and then the microorganisms spread to your sandwich and you get sick
Biological vector
An insect is harboring the microorganism inside its body throughout the organisms life cycle and transmits it into hosts through bites or injections
Vehicle
(1) Non living entity that is the source of infection (2) Can be airborne [dust particles, chicken pox, TB, influenza, measles], food borne , waterborne [cholera, shigellosis, leptospirosis, campylobacter infections]
Aerosol
a cloud of tiny water droplets of fine solid particles suspended in the air
Her immunity
Vaccinate 90-95% of population then that remaining 5-10% unvaccinated gets protected by luck
Diphtheria problem with vaccines talked about in class
Cases are increasing because many people got vaccinates before and since no one was getting sick, they stopped vaccinating and then the disease reoccured (the disease is always present but vaccine helps prevent it from outbreaking]
Isolation
Take sick person with communicable disease and isolate them
Quarantine
Healthy person supposedly infected is isolated to prevent possible spread of disease
Immunization
Get vaccine
Vector control
Monitoring insects, treating the habitats in which rodents and insect live in, with insecticides to prevent infection
CDC
Caries out epidemiological studies published in MMWR which provides readers with disease statistics, gives advice on how to stay healthy and avoid infection and/or disease
WHO
international agency that coordinates and sets up programs to improve health, gives tips on how to stay healthy and not get infections/diseases
Cyclic Diseases
Unpredictable
Ways to Prevent Death
Childhood vaccinations, Bed nets, DOTS [directly observed treatment], IMCI [Integrated management of childhood illness], Antibodies, HIV prevention strategies
Nosocomial infections
Caused by candida albicans, Staph, E.coli, Strep, Pseudomonas
Endogenous infection
Cause by own flora (opportunists) when organism leaves one part of your body and goes into another
Exogenous infection
All tools used in hospital that should be sterilized between patients can spread infectious organisms
Universal precautions
(1) Wear gloves, gowns, masks (2) Discard contaminated needles (3) Clean up bodily fluids properly
Bioterrorism
Weaponizing bombs to hold deadly organisms to kill/infect a large population
