Infection Prevention

Question 1

Many infection are transmissible, what are the 3 methods of transmission?

Answer 1

From non-human source to humans

From person to person- directly

From person to person- indirectly

Question 2

Give some examples of infections that can transmitted on (2)

Answer 2

Food poisoning organism

Rabies

Question 3

Give some examples of infections that can be transmitted from person to person (3)

Answer 3

Influenza
Norovirus
Neisseria gonorrhoea

Question 4

Give an example of a person to person indirect infection/disease, name the vector

Answer 4

Malaria

Mosquitos

Question 5

What are the 4 consequences of transmission?

Answer 5

Endemic diseases

Outbreak

Epidemic

Pande

Question 6

What is a endemic disease?

Answer 6

The usual background rate

Question 7

What is an outbreak of disease?

Answer 7

Two or more cases linked in time and place (linked with incubation period)

Question 8

What is an epidemic?

Give an example

Answer 8

A rate of infection greater than usual background rate

Eg Influenza cases increases during the winter

Question 9

What is a pandemic?

Give an example

Answer 9

Very high rate of infection spreading across many region, countries and continents. Caused by an antigen shift- completely new pathogen therefore no immunity.

Swine flu

Question 10

What are the reasons for outbreaks, epidemics and pandemics?

Answer 10

New pathogens
New hosts
New practice

Question 11

How does a new pathogen cause outbreaks/epidemics/pandemic?

Answer 11

There can be a shift/change in the antigens (eg influenza)/virulence factors (clostridium difficile)/ antibacterial resistance

Question 12

How does a new host cause outbreaks/epidemics/pandemics?

Answer 12

New patients may be: Non immune (from HIV/ cancer patients/ those who are immunocompromised/ immunosuppressive do) or there may be healthcare effects

Question 13

How does a new practice cause outbreaks/epidemics/pandemic?

Answer 13

There can be changes in social customs (tattoos/piercings/sexual promiscuity) or changing in healthcare

Question 14

What is the infectious dose?

Answer 14

amount of pathogen (measured in number of microorganisms) required to cause an infection in the host.

Varies between:

• micro-organism
• presentation of micro-organism
• immunity of potential host

Question 15

What effect does infectious dose have on determine transmissibility?

Answer 15

The smaller the infectious dose, the more likely transmission is because people can become ill from minimal contact and transmission.

Question 16

What sort of graphs do epidemic diseases created?

Answer 16

Bell shaped (from susceptible to infection to recovered)

Question 17

What sort of graphs do outbreak diseases produce?

Answer 17

Short Sharp peaks because the disease is coming and going. rarely regular

Eg norovirus comes every winter and levels die down during the summer

Question 18

What are the methods of interventions to deal with infections in terms of pathogens, patients, practice and place?

Answer 18

Pathogen (+vector): reduction or eradication (disinfection body wash- reduce pathogenic organism/decontamination/sterilisation/destroy animals natural habitat and limit vector numbers)

Patient: improved health (nutrition and medical treatment) and immunity (passive eg maternal antibody, intravenous immunoglobulin (antibodies in blood diffusion) and active- vaccinations-herd immunity)

Practice: avoidance of pathogen or its vector (geographical-not going there/protective clothing and equipments) and behavioural (safe sex/safe disposal of sharps/food and drink preparation)

Place: environmental engineering (safe water/safe air/good quality housing/well designed healthcare facilities)

Question 19

Give some examples of organism that are extinct/ close to extinction due to better control (3)

Answer 19

• smallpox
• polio
• dracunculiasis

Question 20

What are the negative consequences of controlling pathogenic outbreaks?

Answer 20

Decreases exposure to pathogen=decreased immune stimulus=decreased antibody=increased susceptibles=outbreak

Later average age of exposure=increased severity

Eg getting infections like polio, hepatitis A, chicken pox, congenital rubella syndrome at an older age are more severe

Question 21

Give an example of pathogens that cause increased severity with age of host (4)

Answer 21

• polio
• hep A
• chicken pox
• congenital rubella syndrome (particularly bad in pregnant-affects baby)