Lecture 22 viral infection

Question 1

2 types of viral infection in bacterial/archaeal hosts

Answer 1

lytic virulent

lysogenic temperate
prophage copied

Question 2

lysogenic conversion

Answer 2

phage change lysogen phenotype

Question 3

diphtheria

Answer 3

C. diphtheriae
β ptophage
encode diphtheria toxin

Question 4

lysogenic conversion superinfection example

Answer 4

epsilon phage
removes surface receptor
superinfection immune

Question 5

reasoning behind lysogeny

Answer 5

phage > host numbers

nutrient deprived, dormant

Question 6

viral induction

Answer 6

growth conditions, UV irradiation change temperance to virulence

Question 7

acute infection

Answer 7

high progeny

short incubation (12-48hr)
lytic
clinical symptoms

Question 8

latent infection

Answer 8

no progeny
genome + few proteins
no symptom

Question 9

chronic infection

Answer 9

progeny produced
passed to offspring
symptoms present

Question 10

latent infection activation

Answer 10

stress, hormonal change

to acute

Question 11

transformative infection

Answer 11

oncovirus
oncogene products:
inactivate tumour suppressor
hyperactivate protooncogenes

ie HPV cervical cancer

Question 12

inter-host viral transmission

Answer 12

aerosol/airborne (respiratory, secretion)

food/water borne

body fluid/direct contact: blood, semen

zoonotic (infected animals)

vectors/arthropod borne (moz, flies, nematode)

Question 13

intra-host transmission

Answer 13

replicate and disseminate
viremia, spread tissue
2ndary viremia spread
ie neurotropic virus

Question 14

flu

Answer 14

airborne acute
fever, cough, myalgia, headache, anorexia

seasonal epidemic
intermittent pandemics

immunocompromised, pre-existing conditions

pneumonia (2ndary bacterial infection)

Question 15

poliomyelitis

Answer 15

poliovirus (food/water borne) acute,, or CNS chronic paralysis

Question 16

AIDS

Answer 16

direct contact disease
acute/chronic
acute phase (2-8 wk) CD4 infection, fever, headache, rash, weight loss

asymptomatic phase (up to 10yr, disseminate, replicate in lymphoid)

chronic phase: CD4 decrease, abdominal pain, diarrhea

Question 17

zika

Answer 17

acute, mosquito mainly

fever, conjunctivitis, microcephaly

Question 18

avian flu H5N1

Answer 18

pneumonia, ARDS, 50% mortality
lower respiratory vs upper (seasonal human flu)

undercooked poultry