Introduction to microorganisms and infection Flashcards
List in order the 6 stages of the chain of infection
Infectious Agent, reservoir, portal of exit, mode of transmission, portal of entry, susceptible host
List 4 major reservoirs of diseases that infect humans
Humans, animals, soil and water
Diseases that are transmitted from animals are called?
Zoonoses
What is a portal of exit?
How an infectious microorganism leaves the reservoir/human body
List three human portals of exit?
Respiratory, digestive system, skin and blood.
What are the main modes of transmission of disease?
Contact
Common Vehicle
Vector
What is contact transmission?
Direct, indirect, and or droplets
What is common vehicle transmission?
Via air, water and food
What is vector transmission?
mechanical, biological
What is direct contact in the mode of transmission?
Close or intimate contact between the infected host and susceptible individual
What is an indirect contact in the mode of transmission?
microbes transferred from one host to another via a non-living object eg door handle
In the category of contract transmission, what is a droplet transmission?
Where droplets falling less than one metre, (sneezing, speaking etc) can spread droplets from the upper respiratory tract.
In a virus what surrounds the DNZ/RNA?
Capsid
Do all viruses have a membrane-like envelop that surrounds the capsid?
NO
What does obligate intracellular parasite mean?
A virus needs a host in order to replicate.
List the 5 steps of viral replication
Attachment Entry Replication Assembly Release
Name two examples of common viral infections
Common cold, Measles, Mumps
What is a fomite?
An inanimate object like a door handle can be a vehicle for the transmission of an infectious agent.
A fomite is (in the chain of transmission)?
An indirect contact transmission
Common vehicle transmissions (airborne) must be able to survive what sort of conditions?
tolerate dry conditions, outside host
Examples of diseases transmitted via airborne common vehicle transmission?
Measles and chickenpox.
Common vehicle transmission - airborne, organisms must be carried in air current for more than….. …..
one metre otherwise is it a droplets contact transmission. (if less than one metre)
Common vehicle transmission via waterborne transmission occurs…….
when there is faecal contamination of the water used for drinking and bathing
Common vehicle transmission via foodborne transmission occurs ……
when organisms are introduced by poor hygiene, lack of sanitation and or poor food handling. Contaminated food and water.
Vector transmission of infection occurs via two different modes…
Mechanical and Biological