Public Health Biology and Human Disease Risk Flashcards
Models of Disease Transmission
Transmission modeling is often to understand the factors that are responsible for the persistence of transmission, the dynamics of the infection process and how best to control transmission.
What are the main components of the epidemiologic triad?
Agent/pathogen, Host, and Environment
Causative Agent
Any microorganism that can cause infection
Reservoir or Source
The environment where the agent resides; water sources, feces, bodily secretions, etc.
Portal of Exit
How the agent leaves the reservoir or the host
Mode of Transmission
How the agent travels to another host; transmission can be direct or may include an intermediate or indirect contact
Portal of Entry
Where the infectious agent enters a susceptible host.
Susceptible Host
Individual or animal that is susceptible to infection.
What are important characteristics to consider about a host?
- age
- prior exposure
- susceptibility
- co-infection
- immune response
What are important characteristics to consider about an agent/pathogen?
- toxicity
- virulence
- infectivity
- susceptibility to antibiotics
- ability to survive outside the body
What are important characteristics to consider about an environment?
- climate
- physical structures
- population density
- social structure
What are examples of public health interventions that have diminished infectious disease burden?
- clean water
- sanitation
- vaccination
Disability Adjusted Life Years (DALYs)
Metric used to take the morbidity as well as mortality into account when one is calculating the overall burden of disease.
*Often used to determine cost-effectiveness of various disease interventions
Vectorial Capacity
A key metric that determines if a given insect can serve as an efficient biological vector.
Basic Reproductive Number (R)
Key parameter that determines if a pathogen will cause an epidemic or not.
R0
This is the basic reproductive number at time zero and is an estimate of the average number of new cases that the initial infection is capable of spawning.
What does it mean when R = 1?
When R=1, every case of infection will result in an average of one new case and the infection will be in equilibrium.
What does it mean when R > 1?
When R>1, the incidence of the infection will increase and an epidemic will result.
What does it mean when R < 1?
When R<1, the infection will disappear from the population.
What is the SEIR model?
SEIR = susceptible, exposed, infectious, and recovered.
A type of epidemiologic model.
Adaptive Immunity
This type of immunity can be active or passive and can be naturally or artificially acquired.
According to the WHO chronic diseases accounted for ____ of all deaths worldwide in 2012.
The majority of these deaths (____) are attributable to CVD, cancers, chronic respiratory diseases, and diabetes.
68%
82%
Gene defects
point mutations
Cytogenetic defects
results of chromosomal abnormalities
Epidemiologic Transition
The shift toward an increasing global burden of noncommunicable disease.
What are the 3 stages of epidemiologic transition?
- The age of perstilence and famine
- The age of receding pandemics
- The age of degenerative and man-made diseases
What is a challenge to addressing noncommunicable diseases?
There is a relative lack of understanding of the etiology of non-communicable diseases.
Ecobiologic Factors
Ex: air pollution
Factors specific to the host as well as the environment.