Med Micro - Review Questions 2

Question 1

Give some major classes of virulence factors

Answer 1

Adhesins (capsule, fimbrae), enzymes (invasins, extracellular (nutrients)), motility (flagella), immune system avoidance (biofilm, intracellular, evade phagocytosis), siderophores (get iron)

Question 2

Antiphagocytic factors

Answer 2

stop phagocyte killing. Inhibit pH drop in phagosome, destruction of phagosome before pH drop, phagocyte killing (kill before internalized), capsule (slip, cloaking).

Question 3

Bacterial surface function

Answer 3

Covers surface; Protect against antibodies; Escape parts of innate immunity; in Gram -, LPS outside of S layer

Question 4

Stages of infectious disease

Answer 4

Incubation; Prodromal: mild symptoms - not always present!; Illness: signs and symptoms at peak; Decline; Convalescence: repair.

Question 5

What is happening during each stage of infectious disease

Answer 5

Incubation: phagocytosis, adaptive immunity starting up (takes 2-3 weeks); Decline: immune system is winning, or drugs are helping

Question 6

How long does convalescence last?

Answer 6

Depends on how much energy is needed to repair damage from the disease

Question 7

During which stages are we infectious?

Answer 7

During all of them!

Question 8

What is incubation period dependent on?

Answer 8

Infectious dose, site of infection, general health of host, nature of pathogen (some are fast, some slow), virulence factors

Question 9

What are the major pathways for exit of pathogens from the host?

Answer 9

Most of them are the same as the entry. Has to do with microenvironment, need similar binding

Question 10

What is the most common route of exit?

Answer 10

Respiratory tract and GI tract (fecal-oral route)

Question 11

Do all pathogens exit?

Answer 11

No; pathogens that lack a mode of entry that enter via parenteral route would not have a mode exit

Question 12

What is a dead end host?

Answer 12

Does not pass it on to someone else

Question 13

What are reservoirs of infection and why are they important?

Answer 13

Where pathogens hang out waiting to infect (water towers, humans); door handles are not a reservoir, cannot survive for long

Question 14

What are the major reservoirs of infection?

Answer 14

Soil and water; animals; humans.

Question 15

What is the main method of disease transmission? (double check this with Steve*)

Answer 15

Contact: direct (kissing, cough < 1m) and indirect (cough > 1m)*; vector; vehicle: dust, water, cough on a table then someone else touches it

Question 16

How do we classify infection disease?

Answer 16

Body system affected; taxonomy (bacteria, virus, fungus); longevity and severity (chronic or acute); spread to host; effects of populations

Question 17

Define epidemiology

Answer 17

Study of where and when diseases occur and how they are transmitted within populations. Important when Koch’s postulates aren’t possible and to consider traveling etc.

Question 18

What is incidence and prevalence and why is the incidence of infections disease important (what info can it give us)?

Answer 18

Incidence = number of new cases in an area; prevalence is total number of cases.

Question 19

Endemic; sporadic; epidemic; pandemic

Answer 19

General to an area; spike in one area; spike then spread at national level; international

Question 20

How does healthmap work?

Answer 20

Healthmap: Collect reports every hour to track diseases around the globe, publish reports and warnings, share info to promote awareness

Question 21

How does biodiaspora depend on healthmap?

Answer 21

Takes data from healthmap, then adds in other factors to provide thorough analysis of an outbreak

Question 22

What is the goal of biodiaspora?

Answer 22

To prevent the spread of disease, provide awareness, evaluate potential for spread

Question 23

Three approaches to epidimiology

Answer 23

Descriptive: tabulation of data; analytical: probable cause, transmission, prevention; experimental: test hypothesis

Question 24

How do the approaches to epidemiology address Koch’s postulates?

Answer 24

Very important when you cannot use them

Question 25

Nosocomial disease

Answer 25

Infections disease caught from a health care environment

Question 26

3 types of nosocomial disease?

Answer 26

Iatrogenic: from a surgery; endogenous: you have the pathogen but something in environment causes it to cause disease; exogenous: disease caught in hospital

Question 27

What factors are involved in a health care environment that lead to an increase in infectious disease?

Answer 27

Immunocompromised; pathogens that we aren’t exposed to normally; proper hygiene of the staff

Question 28

How does biodiaspora work ?

Answer 28

Integrate infectious disease threats and evaluate risks of spread; data from healthmap; understand the local environment/context of disease: temp, alt, transport; healthcare situation and spending; track number of travellers from regions