IMM - Microbial

Question 1

5 main infectious agents

Answer 1

Viruses
Bacteria
Fungi
Protozoa
Helminths

Question 2

Viruses are

Answer 2

Obligate parasites

Question 3

Obligate parasites

Answer 3

Need a host to replicate

Question 4

How do viruses divide

Answer 4

Budding or cytolysis (transmitted out of cell) - they also show host specificity and replicate using host cell nuclear synthetic machinery - contain RNA or dna

Question 5

Routes of infection

Answer 5

Faecal-oral, airborne, insect vectors, blood borne (his/hep)

Question 6

Reverse transcriptase

Answer 6

Enzyme in retroviruses that convert the RNA genome into double stranded DNA - so that it can integrate itself with host cell machinery

Question 7

Smallpox

Answer 7

Oblligate pathogen (human) - caused by a variola virus

Question 8

Special about smallpox

Answer 8

Characteristic diagnostically

Question 9

Polio

Answer 9

Virus - faecal oral route mainly

Question 10

Bacteria

Answer 10

Prokaryotes - no membrane bound organelles
Haploid - if mutation always dominant
Dicide via binary fission
Cytoskeleton is poorly defined

Question 11

Bacterial capsule

Answer 11

Interferes with phagocytosis

Question 12

Shigella

Answer 12

Bacterial ; faecal-oral route ; destroys epithelium of GI so very bloody and binds to actin in order to move from cell to cell

Question 13

Neisseria meningitides

Answer 13

Gram negative - often causes meningitis or septicaemia - rapid progression - necrotic (amputation)
COLONISATION moves through human populations

Question 14

nosocomial

Answer 14

Originating in the hospital

Question 15

2 types of nosocomial infections

Answer 15

C.difficile ; MRSA

Question 16

Mycobacterium TB

Answer 16

Better vaccines needed + tools for early diagnosis (using fluorescent 18F in thoracic cavity) - greater metabolic activity

Question 17

Helicobacter pylori

Answer 17

Leads to peptic ulcer and gastric cancer ; multiple flagella so very motile

Question 18

Mutation rates?

Answer 18

Point mutation rates are very very low 10^-8 for humans and bacteria BUT generation time for bacteria is a lot lower hence greater chances of mutations being prevalent (also HAPLOID)

Question 19

Fungi

Answer 19

Eukaryotic - systemic/mucosal/cutaneous mycoses

Question 20

What does fungi occur as?

Answer 20

Yeasts or filaments or both

Question 21

Cutaneous meaning

Answer 21

Relating to the skin

Question 22

Filaments

Answer 22

Hyphae

Question 23

Protozoa

Answer 23

Unicellular eukaryotic (intestinal/blood.tissue parasites)

Question 24

How do protozoa divide?

Answer 24

binary fission (double the size) or by formation of trophozoites inside a cell

Question 25

trophozoites?

Answer 25

Active/feeding stage - begin to encyst
Infected cells ready to release into the bloodstream

Question 26

Malaria

Answer 26

Entirely dependent on vector - latitude and altitude

Question 27

Leishmania

Answer 27

Sandfly vector ; blood and tissue parasite and formation of trophzoites inside the cell

Question 28

Visceral

Answer 28

Internal organs of the body

Question 29

Helminths

Answer 29

Metazoa - eukaryotic - life cycles outside human host - main is faecal-oral transmission (hatch in gut and larvae travel different organs)

Question 30

Worms

Answer 30

Roundworms
Flatworms
Tapeworms

Question 31

Schistosomiasis

Answer 31

Very inflammatory ; bury into exposed skin - snail is the intermediate host