Intro To Infection

Question 1

What are the important things to consider when patient presenting with possible infection?

Answer 1

Clinical syndrome 
Pathogen causing syndrome 
Source 
Exposure 
Microbial and host factors I.e. why some might be asymptomatic 
Infection control 
Investigations 
Treatment 
Complications 
Prognosis

Question 2

What might be a sign that someone has an abscess?

Answer 2

Chest infection symptoms not improving with antibiotics

Question 3

What is a reservoir?

Answer 3

Person, animal or plant or substant which an infection agent normally lives in and multiplies and can act as a source for infection

Question 4

What is a zoonosis?

Answer 4

Disease transmitted from animal to human

Question 5

What is human-restricted pathogen?

Answer 5

Pathogen with humans as only reservoir i.e. no animal or environmental reservoir
Eg. Small pox and measles and rubella

Question 6

What is latency?

Answer 6

Ability of pathogen to lie dormant within body with no symptoms and signs

Question 7

What is nosocomial?

Answer 7

Hospital inquired infections

Question 8

What are the different forms of exposure?

Answer 8

Person-to-person

Aerosol

Oral

Fomites (inorganic objects or materials)

Vectors (living organism which can transmit the infection)

Question 9

What is an incubation period and why is it important?

Answer 9

Time taken from exposure to development of disease

- can help to differentiate between which diseases are more likely to be causing the infection

Question 10

What are virulence factors?

Answer 10

Factors which increase degree of pathogenicity

Adhesins (fimbriae, pili, flagella)
-help with adherence

Aggressins (capsule, enzymes, plasmids)
-help invade and evade host

Toxins:
-damages host

Question 11

What are examples of pathogens releasing toxins?

Answer 11

Necrotising faciitis

Toxic shock syndrome

Tetanus toxin= bacterial toxins associated with back muscle contraction and “grinning death” due to damaging CNS

Vibrio toxin= associated with cholera

Question 12

What are the important host factors to consider?

Answer 12

Human microbiome

Immunity

Age and co-morbidity

Pregnancy

Question 13

What is R0? How is this different from R value?

Answer 13

Basic reproduction number based on expected number of secondary cases occurring from a single infection in completely susceptible population

R0 is specific to population which is completely susceptible
R is in population where resistance/immunity/vaccination has occured

Question 14

What are the 2 types of molecular diagnostic tests used with infections? What is the different between a direct and an indirect test?

Answer 14

PCR used to directly look for pathogen= DIRECT

Serology looking at the antibodies produced following infection= INDIRECT

Question 15

How can infections be treated?

Answer 15

Fluids

Oxygen

Anti-microbials