immunology

Question 1

clinical infection

Answer 1

infections with signs and symptoms

Question 2

sub-clinical infection

Answer 2

infection with pathogen but no symptoms

Question 3

latrogenic infection

Answer 3

from a medical practitioner/ intervention (hospital)

Question 4

How are respiratory infections transmitted?

Answer 4

droplets (cough-sneeze), saliva, soil dust, water aerosols

sneezing propels mucus droplets from the respiratory mucosa, transmitting flu or cold virus to a new host

Question 5

Zoonoses is a term used for what kind of disease?

Answer 5

direct animal-to-human, animal-vector-human, human-vector-human

Question 6

endemic

Answer 6

Disease present in a community (region) all the time, usually only clinical in a few

Question 7

epidemic

Answer 7

Wide spread disease within a community (region), affecting many people but only occasionally present

Question 8

pandemic

Answer 8

Wide spread epidemic, not confined to a single community or region (more than one continent)

Question 9

Sporadic

Answer 9

Widely scattered disease, occurring singly, irregularly, infrequently

Question 10

What is “Epidemiology”?

Answer 10

The study of the spread, frequency, distribution of disease

Question 11

Explain the difference between Morbidity and Mortality

Answer 11

Morbidity
- Number made ill by infective agent
Mortality
- Number of deaths caused by infective agent

Question 12

7. Explain the difference between Incidence and Prevalence

Answer 12

Incidence
- Number of new cases over specific period
Prevalence
- Number of cases (infected or diseased) at a given time (old and new cases)

Question 13

In epidemiological terms how would you classify the disease “AIDS”.

Answer 13

pandemic

Question 14

What factors influence the spread of disease in a community?

Answer 14

1. Virulence of the pathogen
2. Pathogen transmission mode
3. Population susceptibility – Immunity

Question 15

List four ways of preventing the spread of disease in a community.

Answer 15

• Prevent contamination of water supplies
• Immunization
• Educate the public
• isolate diseased persons

Question 16

Which disease of the following disease type would most likely spread quickly through the Perth community and why? A) Gastroenteritis, B) A sexually transmitted disease, C) a Respiratory disease

Answer 16

C) a respiratory disease as Perth’s population tend to have higher hygiene standards and good public education, making gastroenteritis and STI less likely to spread quickly. A respiratory disease may be spread via droplets, and so when people cough or sneeze without covering, infectious pathogens can be transmitted.

Question 17

List the stages of infectious disease

Answer 17

incubation 
prodromal 
invasive 
decline
convalescence

Question 18

What are the two branches of the immune system?

Answer 18

innate and adaptive

Question 19

How does skin protect against bacteria?

Answer 19

innate: first line of defence; mechanical barrier

it is difficult for microbes to penetrate the skins dry, dead out cells. In addition, the sebaceous glands produce oils which also help to kill microbes

contains normal flora to provide competition for pathogenic microbes that want to grow on the skil

Question 20

what types of WBCs are phagocytic

Answer 20

Neutrophils, monocytes, eosinophils

Question 21

What type of white blood cell (WBC) is mainly involved in the adaptive immune system?

Answer 21

Lymphocyte- T and B cells

Question 22

What antibody types are involved in the primary and secondary immune response?

Answer 22

Primary response - Immunoglobulin M (IgM)

Secondary response - Immunoglobulin G (IgG)

Question 23

What type of lymphocyte is involved in cell mediated immunity?

Answer 23

Cytotoxic T Cells and natural killer cells

Question 24

List the ways antibodies fight infection.

Answer 24

Activate complement

trigger phagocytosis

neutralise viruses and toxins

agglutination

Question 25

9. List the antibody isotypes .

Answer 25

IgG
- Monomer, most abundant in serum – largest amount, long term immunity, can cross placenta

IgA
- Monomer in serum, dimer in saliva and secretions, most abundant total – saliva and mucosal surfaces, tear, nasal fluids, milk

IgM
- Pentamer, primary response – first Ab to appear during an infection

IgE
- Monomer, stem binds mast cells, basophils and eosinophils causing release if granules – anti-parasite, allergy

IgD
- Monomer, attached to B cells, antigen receptor for activation – largest Ab - Ag receptor on B cells

Question 26

What are the 4 cardinal signs of inflammation and how do they come about?

Answer 26

redness (increased blood flow)
heat (increased blood flow)
swelling (lymphatic fluid)
pain (inflammatory substances released cause pain)

Question 27

Describe the difference between humoral and cell mediated immune responses.

Answer 27

humoral immunity - antibody mediated, action against extracellular invaders, produced by B lymphocyte, uses antibodies as main form of immune response

cell mediated immunity - lymphocyte directly/ indirectly kill infected cells, act against intracellular invaders, cytotoxic T cells (Tc), uses cytotoxic T cells and natural killer cells as main form of immune response

Question 28

List and describe the types of T cells

Answer 28

cytotoxic T cell - destroys host cells that harbor anything foreign, directly responsible for cell mediated immunity

T helper Th - modulate activities of other immune cell - stimulate

T regulator Treg - turn off an immune response - inhibit

Question 29

What is the MHC and what is its purpose?

Answer 29

MHC refers to the Major Histocompatabilty Complex. The function of MHC is to bind peptide fragments derived from pathogens and display them on the cell surface for recognition by the appropriate T-cells. The consequences are almost always deleterious to the pathogen; viruses infected cells are killed, macrophages are activated to kill bacteria living in their intracellular vesicles, and B-cells are activated to produce antibodies that eliminate or neutralise extracellular pathogens

Question 30

Describe the difference between passive and active immunity.

Answer 30

• Passive immunity relies on the administration of
  antibodies (already directed against an antigen),
  whereas active immunity involves the administration
  of the antigen.
• Passive immunisations are generally administered
  post infection/toxin, wheres active immunisations are
  prophylaxis, to prevent future infection.
• In passive immunity, the recipient does not produce
  an immune response of their own, unlike in active
  immunity where they produce their own antibodies
  and memory cells.
• Passive immunity is short lived, whereas active
  immunity is long term.

Question 31

How do autoimmune diseases occur?

Answer 31

Autoimmune diseases occur when, instead of attacking foreign bacteria, viruses, or other sources of infection, the immune system attacks healthy organs and tissues. It’s not known why this happens, although conditions most often affect people with a genetic predisposition. Type 1 diabetes is an example.