Term
| What does the epidemiologic triad state? |
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Definition
states that in order for a disease to occur there must be a harmful agent that comes in contact with a susceptible host in the a certain environment.
The occurrence of a disease can be blocked by intersecting the triangle at any of its three sides. |
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Term
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Definition
can be anything from innate or genetic susceptibility to disease to psychosocial factors.
Interventions targeting the host can be
hygienic measures
quarantine
immunization
antimicrobial interventions
carrier elimination |
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Term
| What are environmental barriers? |
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Definition
anything from the availability of vectors, to weather, or seasonality patters, to the existence of reservoir hosts.
environmental interventions - target vectors or reservoirs and their habitat, adequate handling and tx of water and waste, appropriate food handling, control of temp, ventilation |
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Term
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Definition
persistence
survivability
production of toxins
other virulence factors
interventions - steralization, disinfection |
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Term
Noncommunicable infectious diseases
(5) |
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Definition
1. NF is source (perforated bowel)
2. preformed microbial toxins as source (food poisoning)
3. environmental pathogens (tetanus)
4. Zoonoses - human as a receptive but otherwise dead-end host |
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Term
What are the ways communicable diseases are spread?
(9) |
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Definition
1. horiztonal
2. vertical (mother to child, transplacental, birth canal, breastfeeding)
3. zoonoses |
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Term
What are the types of horizontal ways communicable infectious diseases are spread?
(9) |
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Definition
1. respiratory/airborne
2. saliva
3. GI transmission (fecal oral route)
4. skin to skin
5. bloodbourne
6. sexual
7. autoinoculation
8. eye to eye
9. formites |
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Term
| What is the most common for of person to person transmission as well as the most difficult to control? |
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Definition
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Term
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Definition
| the size of respiratory droplets |
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Term
List what each size of droplet nuclei does (does it remain or fall out of air...ect.)
>100um
<10um
>6um
<5um |
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Definition
>100um droplets fall out of air and settle on surfaces
<10um droplets remain in air for almost 20min
>6um droplets are trapped by nasal mucosa due to the vortex action of the turbinates
<5um droplets stay suspended in air for more than 20min and can attach to all levels of upper and lower respiratory tree. particularly important in the transmission of respiratory infections.
drops can also land on hands or objects and then be transferred to the respiratory or ocular mucosa |
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Term
What are the routes of GI transmission?
(4) |
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Definition
1. feces-hand-mouth
2. feces-object-mouth
3. feces-food/water-mouth
4. anilingus |
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Term
What are some examples of skin to skin transmission?
(3) |
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Definition
1. Stap aureus and Strep pyrogenes
2. Dermatophytoses (ringworm, athletes foot)
3. Herpes gladitorium |
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Term
| Describe two ways that bloodborne pathogens may be transmitted. |
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Definition
1. Arthropod borne..replication in insect vector..mosquitos and malaria
2. human to human (HIV, hep B, hep C) |
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Term
| Discuss incidental vs exclusive tranmission of genital/sexual pathogens. |
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Definition
Incidental - kid touching anus and then sucking thumb
Exclusive - only transmitted through sexual contact (sexually transmitted infections, STIs) |
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Term
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Definition
| occurs when a person incidentally transfers pathogens from one anatomical site to another |
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Term
| How are eye to eye infections spread and by what main bacteria? |
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Definition
spread by contaminated fingers, implements, surfaces, formites, or vehicles such as flies
1. Strep, Haemophilus, adenovirus can all cause conjunctivitis
3. Chlamydia trachomatis causes trachoma |
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Term
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Definition
inanimate objects that harbor pathogens and transmit them to a new host.
can include towels, toothbrushes, clothing, tables, doorknob |
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Term
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Definition
infections spread from animals to humans
they tend to be more serious and often fatal in humans then in their natural animal reservoir |
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Term
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Definition
the indirect effect of protection from infection of otherwise susceptible members of a pop and the pop as a whole as a result of the presence of immune individuals.
can be from acquired active or acquired natural immunity.
Relies on immune indiviual in pop to provide a FIREWALL against the spread of a disease. |
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Term
| What are the four things herd immunity is dependent on? |
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Definition
1. attack rates of etiologic agent
2. past infection hx of population
3. acquired active immunity rates
4. population health status (nutrition, comorbidities) |
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Term
What are three examples of herd immunity?
(specific diseases) |
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Definition
1. pertussis (high attack rate, 90-94% immunological protection for herd immunity)
2. measles (high ar, 83-94% needed for herd immunity)
3. mumps (mod ar, 75-80% needed for herd immunity) |
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Term
The incubation period is a the time between exposure to a pathogen and appearance of the first symptoms of disease. What does the range of time between the two reflect?
(5) |
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Definition
1. dose (higher dose = shorter incubation
2. replication rate (fast = short incubation)
3. status of host (healthy vs immunocompromised)
4. site of inoculation and distance to targeted tissue
5. other facts such as genetic susceptibility to disease
note: fast replication also usually = acute disease. slow = chronic disease |
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Term
| Why is the incubation period a critical epidemiological factor for recognizing and diagnosing infectious diseases? |
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Definition
it allows one to rule out or rule in potential sources of infection and identify who has been exposed
essential in understanding time-space clustering and investigating outbreaks.
-some infectious diseases are transmissible during incubation period.
-some diseases have short incubation, short run of disease but person may still be able to pass disease even w/out signs and symptoms.
-prolonged incubation periods allow for intervention w/ chemoprophylaxis or immunoprophyaxis (tetanus and rabies) |
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Term
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Definition
the number of NEW OCCURRENCES of disease, injury or death in the study of a population during THE TIME PERIOD BEING EXAMINED
if incidence increases so does chance of getting disease
can have SEASONALITY = risk of getting disease greater in a certain time of year (flu during winter) |
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Term
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Definition
total number of existing cases with respect to the entire population x 100%
incidence of new cases + old cases |
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Term
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Definition
| total number of deaths in a pop due to disease |
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Term
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Definition
| total number of persons afflicted w/ infectious diseases |
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Term
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Definition
rate at which infection or disease is present
a certain constant rate |
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Term
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Definition
a significant increase (sudden) above the endemic and sporadic rate of a disease
-time period is not defined |
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Term
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Definition
| all individuals are exposed to specific source |
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Term
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Definition
| all individuals are exposed to a specific source at a particluar time |
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Term
| propagative or progressive epidemics |
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Definition
| indicates a tramissible or communicable disease |
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Term
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Definition
global epidemic
-above the normal global endemic rate |
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Term
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Definition
| occasional cases at irregular intervals in random locales |
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Term
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Definition
an attribute, characteristic, agent that is or is suspected to be related to the occurence of a particular disease.
OFTEN AS IMPORTANT OR MORE IMPORTANT THAN THE SIGNS AND SYMPTOMS FOR RULING IN/OUT A DISEASE |
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Term
| 9 examples of risk factors |
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Definition
1. age
2. gender
3. genetics
4. occupational/behavioral
5. geographic
6. socioeconomic, nutritional
7. seasonality
8. environmental
9. factors affecting virulence (dose, rate of growth, toxin/exotoxin, endotoxin/lps) |
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