Infection Control - Disease Transmission

Question 1

What are some environments where microbes can exist?

Answer 1

People, animals, n on-living substances such as soil, water, food.

Question 2

For infectious disease to spread, infectious agents must be able to enter and exit hosts. What are portals of entry?

Answer 2

Mucous membranes:

• Respiratory tract/inhalation of moisture or dust particles/pneumonia, flu
• Gastrointestinal tract/food, water, any object into mouth/salmonella, cholera
• Genitourinary tract/STDs/Gonorrhea, HIV
• Conjuctiva/eyes/conjunctivitis

Skin:
- Anything that disrupts skin integrity/cuts, wounds, burns, IV

Question 3

What are some portals of exit?

Answer 3

Upper respiratory tract - talking, coughing, sneezing

Gastrointestinal tract - faeces, saliva

Skin - via contact or skin dust

Urogenital tract - urine, semen, vaginal secretions

Blood - needles, wounds, insects, blood exchange, medical procedures

Question 4

What are some direct contact modes of transmission?

Answer 4

Direct contact - involves close contact with an infected person e.g. colds, STDs

Droplet transmission - Aerosols produced, but only travel a short distance and still need to be in close proximity to infected person e.g. coughing, sneezing, talking

Question 5

What are some indirect modes of transmission?

Answer 5

Indirect contact - Transmission has not occurred due to close contact with an infected individual

Fomite transmission - An inanimate non-living object is contaminated

Vehicle transmission - transmission via a medium e.g. contaminated food, water, air (aerosol), IV fluid

Common vehicle transmission - multiple peopl,e infected from the one source e.g. all ate the same dish

Aerosol - Aerosols produced but this time travel long distances e.g. infectious particles spread through AC ducts

Question 6

What is vector transmission?

Answer 6

Transmission via a non-human living organism, usually an insect

Mechanical vector transmission - animal/insect is not infected , but is contaminated e.g. fly crawls through rubbish

Biological vector transmission - Insect is infected with the microbe itself and is part of the life-cycle of microbe e.g. ross river fever, malaria