microbiology

Question 1

ectoparasites

Answer 1

head lice, scabies, ticks, fleas; parasite that lives on the exterior of its host

Question 2

head lice (pediculus humanus capitis)

Answer 2

wingless insects, transferred by hair-hair contact, treated by combing or lotions (hedrin)

Question 3

scabies (sarcoptes scabei)

Answer 3

small mites that burrow into skin, contagious and cause allergic reaction like symptoms; itchy pimple-like rash
treatment: permethrin, ivermectin

Question 4

ticks

Answer 4

live on skin and feed off blood
transmit lyme disease, typhus
removed with tweezers

Question 5

fleas

Answer 5

wingless insects that can jump, eggs may stay in carpets for a week
transmit typhus (rickettsia bacteria)

Question 6

mosquitoes transmit

Answer 6

malaria, dengue, yellow fever, chikungunya, elphantiasis

Question 7

sandfly transmits

Answer 7

leishmania which is a protozoal infection

Question 8

tsetse fly

Answer 8

transmits trypanosoma which resides in blood and enters CNS causing neuronal damage and causing sleeping sickness

Question 9

reduvid bug

Answer 9

chagas disease (trypanosoma)

Question 10

simulum fly

Answer 10

onchocerciasis (river blindness)

Question 11

endoparasites

Answer 11

parasites which live inside a host and inhabit the gut, lungs, heart and blood vessels

Question 12

roundworms (nematodes)

Answer 12

intestinal nematodes:
cause diarrhoea, itch and anaemia
required orally or transmitted through faeces
extraintestinal nematodes:
trinchinella - present in infected meat and cysts in muscle

Question 13

tapeworms

Answer 13

cestodes: flat segmented worms with both female and male organs

Question 14

echonococcus granulosus

Answer 14

worms found in the gut of dogs
eggs release larvae in gut causing cysts in liver that can burst

Question 15

pork tapeworm (taenia solium)

Answer 15

pigs are infected from ingesting human faeces - humans ingest uncooked pork
eggs are released in duodenum
larvae are carried in blood to CNS and become encysted (cysticercosis) causing pain and neurological problems - epilepsy

Question 16

flukes (multicellular treatodes)

Answer 16

reside in blood (veins), guts, lungs
eggs become encysted in the liver, bladder, lungs, CNS
causing schistosomiasis

Question 17

liver fluke (fasciola hepatica)

Answer 17

penetrates through colon wall and goes to liver via hepatic portal vein
causes cirrhosis/liver damage which induces jaundice

Question 18

protozoal infections

Answer 18

single celled (eukaryotic) parasites which asexually reproduce inside human host
can be extracellular or intracellular
can be ingested or transmitted by blood transfusion, open wounds in aqueous environments, injected by ectoparasites in a blood meal

Question 19

waterborne protozoal infections

Answer 19

giardia lamblia: causes GI upset and diarrhoea
Entamoeba histolytica: causes severe bloody diarrhoea and abscesses in brain
trichomonas: sexually transmitted disease, infects urinogenital tract causing vaginitis

Question 20

insect-borne protozoal infections

Answer 20

Trypanosoma: transmitted by tsetse fly, extracellular and resides in blood
leishmania: transmitted by sandfly resides in macrophages causing skin sores and lysis of WBC
toxoplasmosis: from cat faeces, may cause foetal damage and schizophrenia

Question 21

malaria

Answer 21

mosquito borne protozoal infection
plasmodium infection, untreated it results in cyclic fever/chills and destruction of RBC

Question 22

life cycle of malaria

Answer 22

sporozoite is injected into human by mosquito and moves to liver forming a cyst which bursts open from hepatocytes releasing merozoites which infect RBC
they hoover up nutrients then burst cell - causing anaemia
releasing secretory granules/process haemoglobin - causing fever

Question 23

viruses

Answer 23

parasites, non-living, hijack cellular process and produce virally encoded proteins and replicate genetic material
cannot reproduce asexually require host

Question 24

viruses and their route of transmission

Answer 24

• polio/hepatitis A: faecal/oral route
• rabies: bite of infected animal
• herpes/HPV/HepB/HIV: sexually transmitted
• ebola: all body fluids/tissues
• ifluenza/colds/MMR: respiratory
• yellow fever/dengue fever/chikungunya: insect vectors

Question 25

prion disease

Answer 25

prion protein disease - rare, fatal neurodegenerative disease protein misfolding disease clinically characterised by dementia and ataxia(staggering gait) pathology characterised by neuronal loss, gliosis and spongiform change in brain

Question 26

PrPc (cellular prion protein)

Answer 26

- normal cellular isoform - monomeric and soluble - protease sensitive neuroprotective against oxidative stress

Question 27

PrPsc (disease-specific protein)

Answer 27

- disease associated isoform - aggregated and insoluble - partially protease resistant - infectious and toxic: act as template to fold normal proteins into abnormal shape making them toxic

Question 28

eukaryotes

Answer 28

- large cells - organelle present - multiple linear chromosomes - some have cell walls (fungi)

Question 29

prokaryotes

Answer 29

- small cells - organelles absent - 1 circular chromosome + plasmid - cells walls (bacteria)

Question 30

types growth media

Answer 30

- peptone (proteins) - lactose (carbohydrates) - bile salts + crystal violet (inhibit gram + bacteria) - neutral red (pH indicator)

Question 31

bacteria that use lactose

Answer 31

E. coli, Klebsiella turn lactose into lactic acid lowering pH red colonies formed with surrounding precipitated bile salts causing haziness

Question 32

bacteria that do not use lactose

Answer 32

Salmonella, Pseudomonas aeruginosa use peptone which forms ammonia causes higher pH yellow medium agar and colourless colonies

Question 33

gram + bacteria structure

Answer 33

- peptidoglycan layers - cytoplasmic membrane

Question 34

gram - bacteria structure

Answer 34

- lipopolysaccharides - cytoplasmic membrane (outer) - peptidoglycan layers - cytoplasmic membrane (inner)

Question 35

porins

Answer 35

found in gram negative bacteria outer membrane and let small hydrophilic molecules go through

Question 36

gram - cocci

Answer 36

- staphylococcus aureus - streptococcus pyogenes - enterococcus faecalis

Question 37

gram - cocci

Answer 37

- Neisseria gonorrhoeae - Neisseria meningitidis

Question 38

gram + rods

Answer 38

- clostridium difficile - clostridium botulinum - clostridium perfringens - clostridium tetani

Question 39

gram - rods

Answer 39

- Escherichia coli - pseudomonas aeruginosa - Klebsiella pneumoniae

Question 40

mycobacteria

Answer 40

mycobacterium tuberculosis - TB mycobacterium avium complex - TB like pulmonary infection in immunocompromised patients mycobacterium Leprae - leprosy

Question 41

symptoms of TB

Answer 41

- appetite loss - fatigue - chest pain - coughing up blood - productive prolonged cough - night sweats - pallor

Question 42

pathogens with capsules

Answer 42

gram - bacteria: - E.coli - Klebsiella pneumonia - haemophilus influenzae (rod) - neisseria meningitidis gram + bacteria: - streptococcus pyogenes - streptococcus pneumoniae fungi: Cryptococcus neoformans

Question 43

bacteria with endospores

Answer 43

- all clostridium species - bacillus anthracis (anthrax) - bacillus cereus (food poisoning)

Question 44

Clostridium difficile

Answer 44

gram + rod pseudomembranous colitis - diarrhoea, abdominal pain usually following antibiotic treatment and changes in normal gut flora

Question 45

fungi

Answer 45

yeasts (unicellular) moulds (multicellular) structure: proteins, beta-glucans, chitin, cytoplasmic membrane (ergosterol)

Question 46

yeasts

Answer 46

candida albicans - oral/genital infections Cryptococcus neoformans - meningitis

Question 47

moulds

Answer 47

aspergillus - aspergillosis aflatoxin - liver cancer