Chain of Infection [Batch 2027] Flashcards
● First link in the chain of transmission
INFECTIOUS AGENT
Infectious microorganism or pathogen
○ Bacteria
○ Fungi
○ Virus
○ Parasite
● Habitat in which a pathogen lives, flourishes and mutiplies
Resorvoir
● The reservoir may or may not be the source from which an agent is transferred to a host
Resorvoir
○_________ and _____-reservoirs can and cannot manifest symptoms but either way, will still be capable of transmitting pathogens
Human
Animal
● The pathogen leaves its host
PORTAL OF EXIT
PORTAL OF EXIT
● It can be through:
○ Coughing
○ Sneezing
○ Crossing the placenta
○ Through wounds
○ Blood sucking arthropods (malaria)
● The agent may be transmitted from it’s reservoir to a susceptible host
MODES OF TRANSMISSION
● Occurs when there is physical contact between an infected person and a susceptible person
DIRECT TRANSMISSION
○ Skin-to-skin contact
○ Kissing
○ Sexual Intercourse
○ Contact with soil or vegetation harboring infectious organisms
● Direct contact
○ Relatively large, short-range aerosols produced by sneezing, coughing, or talking
○ Can spread up to 2 meters
Droplet Spread
● Occurs when there is no direct human-to-human contact
INDIRECT TRANSMISSION
○ Carried by dust or droplet nuclei suspended in the air
○ Less than 5 microns in size
● Airborne
○ Passively carrying a pathogen
■ Provide an environment in which the agent can grow
Vehicles
■ Blood meal
○ Biological vectors
■ Flies can pick up infectious agents on the outside of their bodies and transmit them through physical contact
○ Mechanical vectors
● Manner in which a pathogen enters a susceptible host
PORTAL OF ENTRY
● Final link in the chain of infection
● Susceptibility of an individual depends on their body’s ability to resist the infection or limit pathogenicity
SUSCEPTIBLE HOST
● Characteristics that may increase the risk of human disease
○ Age
○ Sex
○ Occupation
○ Genetics
○ Immune status
○ Race
○ Religion
● A person or animal that harbors a specific infectious agent without discernible clinical disease and serves as a potential source of infection
CARRIER
● Healthy carrier
● Do not manifest the apparent signs or symptoms that indicate that one is infected
ASYMPTOMATIC CARRIER
● Incubatory carrier
● With clinically recognizable disease
CONVALESCENT CARRIER
○ Food safety
○ Environmental cleaning and disinfection
○ Respiratory etiquette
● Controlling or eliminating agent at source of transmission
○ Performing hand hygiene
○ Wearing complete PPE when necessary
○ Handle needles and other sharps objets safely
○ Avoid sharing of items
● Protecting portals of entry
