L5 Viral pathogenesis 1

Question 1

how can humans transmit to other humans

Answer 1

direct contact e.g.sexual

environmental e.g. faecal oral, aerosols

Question 2

what is a chronic carrier

Answer 2

shed virus for long period, can be for life – persistent, virus actively replicating

Question 3

what is an acutely infected individual

Answer 3

over short period spread virus

Question 4

how do animals spread viruses to humans

Answer 4

direct bite
insect transmission
environmental
zoonosis – transmission across species barrier, e.g. SIV=HIV

Question 5

what is the respiratory route of infection

Answer 5

sneezing, coughing
inhale the aerosol droplets
contaminated surface - touch mouth/nose/eyes (rhinovirus esp)

Question 6

what protects against airborne viruses

Answer 6

cilia and mucus provide important physical protection

Question 7

what is the best environment for virus survival

Answer 7

dry and cool e.g.steel

Question 8

how is the GI tract infected

Answer 8

faecal oral route

food and water contamination

Question 9

what virsues are faecal oral infectors of GI tract

Answer 9

Enteroviruses (Coxsackie, Polio etc.), Small Round Structured Viruses, norovirus

Question 10

what must the virus be like to survive in the GI tract

Answer 10

acid stable

non-enveloped (bile salts)

Question 11

why cant GI tract viruses be enveloped

Answer 11

duodenum – bile salts released here, they’re emulsifiers (kill envelope viruses)

Question 12

how is rotavirus activated in the body

Answer 12

rotavirus isn’t infective until it gets activated by acid – pH changes, protein changes

Question 13

how do viruses infect via the transcutaneous route

Answer 13

insect/animal bite

IDVA, needle stick injury, transfusion

Question 14

how is the transcutaneous route protected

Answer 14

skin

Question 15

how does the bite location affect infection

Answer 15

If bitten in the neck isn’t as far to travel to head but leg is longer for infection – replicates in brain and changes the behaviour of the animal

Question 16

how does HIV risk change with genitial tract infection

Answer 16

more at risk as already compromised
up-regulation of virus receptors
infiltration of permissive cells

Question 17

genital tract or rectal mucosa infections

Answer 17

HSV2 (and HSV1)
CMV
HBV
HPV
HIV

Question 18

what is an acute infection

Answer 18

short lived

Question 19

what is a persistent/chronic infection

Answer 19

virus always replicating and releasing

Question 20

what is a latent infection

Answer 20

infected and virus becomes dormant, expresses latency genes – eventually immune response isn’t sufficient to keep virus under control - remerges

Question 21

why are you susceptible to re-infection by some acute viral infections

Answer 21

short-lived immunity

immune escape due to mutations, genetic drift, genetic shift

Question 22

examples of genetic drift

Answer 22

RSV and influenza

Question 23

examples of genetic shift

Answer 23

influenza A

Question 24

what is genetic shift

Answer 24

two viruses e.g. human and a chicken virus infect e.g. pig = genes moved between and lead to new viruses – new pieces of material

Question 25

what is genetic drift

Answer 25

mutated via point mutations that the immunity doesn’t recognise it anymore

Question 26

what does hep B virus cause

Answer 26

chronic liver disease and occasionally hepatocellular carcinoma

Question 27

how many can clear the hep B virus

Answer 27

90%

Question 28

how many will die from hep B

Answer 28

<1%

Question 29

how many will be chronic hep B carriers

Answer 29

10%

Question 30

what virus is hep B

Answer 30

RT DNA virus

Question 31

what virus is hep C

Answer 31

+ strand RNA virus

Question 32

how many have chronic hep C infection

Answer 32

~80% cases

Question 33

what can 10-30 years chronic hep C infection cause

Answer 33

cirrhosis and HCC

Question 34

what is hep C associated with

Answer 34

``` non-hepatic disease mixed cryoglobulinaemia (don’t make same number of antibodies as normal) ```

Question 35

what is the chronic infection of HIV

Answer 35

100%

Question 36

what does HIV cause

Answer 36

AIDS

Question 37

what are the progression rates of HIV

Answer 37

1-15 years

Question 38

what is the primary infection of herpesvirus

Answer 38

varicella- chickenpox

Question 39

examples of latent infection

Answer 39

varicella zoster virus | epstein barr virus

Question 40

what is the latent site for varicella zoster virus

Answer 40

neurones

Question 41

what is the latent site for epstein barr virus

Answer 41

B lymphocytes

Question 42

what causes secondary or reactivation of latent viruses

Answer 42

host/environmental factors, usually associated with suppression of immune system

Question 43

what viruses are associated with cancer

Answer 43

papillomaviruses - cervical human herpesvirus 8 chronic hepatitis - hepatocellular carcinoma

Question 44

what does human herpes virus 8 cause

Answer 44

EBV immortalisation of B cells

Question 45

what does chronic hepatitis cause

Answer 45

inhibition of apoptosis

Question 46

what is CPE

Answer 46

cytopathic effect | viruses grow some cells morphologically change

Question 47

examples of virus cells that can undergo CPE

Answer 47

primary cell cultures | continuous (cancer) cell lines

Question 48

what are diagnostics of CPE

Answer 48

syncytia or multinucleated cells cell lysis inclusion bodies

Question 49

what do influenza viruses cause

Answer 49

epithelial cell death

Question 50

what is the effect of epithelial death in influenza

Answer 50

give rise to opportunistic secondary bacterial infections (pneumonia)

Question 51

what are the types of acute infection

Answer 51

symptomatic | asymptomatic

Question 52

what is a factor of infection risk

Answer 52

age dependent

Question 53

what are the early acute symptoms

Answer 53

fever aches shivers

Question 54

what are the symptoms of HSV, VZV, hand foot and mouth

Answer 54

vesicles

Question 55

what are the symptoms of MMR

Answer 55

rash

Question 56

what are the clinical symptoms of human papilomavirus

Answer 56

warts | genital warts - associated to cancer

Question 57

how is human papillomavirus transmitted

Answer 57

direct contact | contaminated surfaces/fomites

Question 58

what is the effect of congenital rubella

Answer 58

severe life threatening disease infected infant has abnormalities infect fetus in the placenta TORCH syndrome