4 Infection Transmission

Question 1

What steps make up the chain of infection?

Answer 1

Infectious agent - reservoir- portal of exit- mode of transmission- portal of entry- susceptible host

Question 2

List some factors affecting the transmission of an infection.

Answer 2

Host agent interaction, pathogenicity and virulence, mode of spread, mechanism of disease production, infectious dose, antigenicity

Question 3

State 6 methods of disease transmission (think direct, indirect, vector).

Answer 3

Direct: person to person, droplet
Indirect: fecal-oral, airborne
Vector: fomites, insect bites
(Fomites= inanimate object that serves as vehicle to pass on infectious disease)

Question 4

Examples of diseases spread by direct or indirect contact include MRSA and C.difficile. What isolation would a patient with these diseases require?

Answer 4

Isolation in singe room, door closed

Contamination within 3 feet of bed BUT infectious agents do not stay suspended in air for long

Question 5

Examples of diseases spread by droplet include SARS and adenovirus. What isolation would a patient with these diseases require?

Answer 5

Isolation in room with door closed

Contamination within 6-10 feet of patient

Question 6

Examples of diseases spread as airborne particles include: TB, chickenpox, aspergillus. What isolation would a patient with these conditions require?

Answer 6

Negative pressure isolation room - particles stay suspended in air for long time after