Factors in disease spread Flashcards
What is the name of the model that highlights the links between agent, environment and host in disease causation?
the epidemiological triad
What are the three components of the epidemiological triad?
1) environment
2) agent
3) host
Give four factors that influence an infectious agent’s ability to cause disease:
1) infectivity
2) pathogenicity
3) virulence
4) minimal infectious dose
Define infectivity:
ability of a biological agent to enter and grow in the host
Define pathogenicity:
the ability of an agent to cause disease in a host
Define virulence:
the extent of disease an agent can cause within a host
Define minimal infectious dose:
the amount of a pathogen that is required to establish an infection
Give 6 examples of host factors that increase risk of disease causation:
1) genetics
2) age
3) lifestyle
4) nutritional status
5) psychological health
6) immune status
Give 6 examples of environmental factors that increase risk of disease causation:
1) geography
2) climate
3) agriculture
4) infrastructure
5) social conditions
6) economic conditions
Define communicable disease:
an infectious disease transmissible by direct contact with an affected individual or the individual’s discharge or by indirect means through a vector
Define transmission:
the process by which an infectious agent passes from an infected host to a susceptible host
Define transmissibility:
the ability of an infectious agent to pass from an infected host to a susceptible host
What are the three steps of the ‘chain of infection’?
1) agent leaving its host/ reservoir
2) undergoing mode of transmission
3) entering susceptible host
Define reservoir:
a location where an infectious agent can survive and multiply
What is a convalescent carrier?
those who have recovered from their illness but remain capable of transmitting to others (still host some infectious agent)
