12. viruses & disease

Question 1

properties of viruses 4

Answer 1

intracellular parasites
cause wide variety of diseases
few licensed antiviral drugs
vaccination where possible

Question 2

morphology of viruses 2

Answer 2

helical or icosahedral

naked or membrane bound

Question 3

inhalation

Answer 3

virus transmission by respiratory tract

Question 4

ingestion

Answer 4

virus transmission by GI tract (mostly naked viruses)

Question 5

inoculation

Answer 5

transmission through skin or mucous membrane

Question 6

Iatrogenic

Answer 6

virus transmission unintentionally caused by a doctor, eg thorugh blood transfusion or transplant eg rabies

Question 7

congenital

Answer 7

virus transmission from mother to foetus eg rubella

Question 8

laboratory aetiological diagnosis (cause of disease) can be established by demonstration of

Answer 8

whole virus EM
viral antigen immunological tests
viral nucleic acid PCR
specific antibody response IgM/IgG in blood

Question 9

picornaviruses

Answer 9

family picornaviridae

ssRNA isocohedral naked small RNA virus

Question 10

four genuses of picronaviruses are

Answer 10

enterovirus eg CNS, polio
Hepatovirus eg Hepatitis A
rhinovirus common colds
Aphthovirus Foot and mouth diease in cattle

Question 11

polio virus (enterovirus)

Answer 11

is part of family picornaviridae
spread by faecal oral route
symptoms caysed by spreading along axons
95% individuals aymptomatic
5% flaccid paralysis
vaccination could potentially lead to global eradication

Question 12

rhinoviruses (family picornavirus)

Answer 12

rhinos = nose 
ssRNA non enveloped 
cause of common cold 
100 serotypes as virus mutates easily 
spready by respiratory droplets 
infectious from 1 day after infection -> end of symptoms

Question 13

influenza diseases

Answer 13

family orthomyxovirus 
ssRNA enveloped 
Type A causes the most world epidemics
secondary bacterial pneumonis can kill old and young 
4000 deaths annually

Question 14

influenza viruses (4)`

Answer 14

defined by haemma glutenin (H x 16) antigens
neuraminidase (N x 9) antigens
reservoir for all H&N antigens is in aquatic birds
ssRNA high mutation rates -> annual vaccines

Question 15

Tamiflu and relenza

Answer 15

drugs which block the exit of the viruses

Question 16

herpesviridae (DNA)

Answer 16

3 sub families
alphaherpesviridae
betaherpesviridae
gammaherpesviridae

Question 17

alphaherpesviruses

Answer 17

familie herpesviridae
icosahedral and envelope (dsDNA)
all establish latency in host after primary infection
herpes simplex virus NSV travels up sensory nerves to dorsal root ganglion (latency) until activated
very common, in 40 to 80% of the population

Question 18

heroes simplex virus type 1 HSV1

Answer 18

upper body infections
can be subclinical in most cases
40 to 80% of population have ABs to HSV1

Question 19

acyclovir ACV

Answer 19

blocks DNA synthesis, used to treat cold sores caused by HSV

Question 20

varicella zoster virus VZV

Answer 20

family herpesviridae 
icosahedral + envelop ds DNA 
chicken pox 
latent in dorsal root ganglions
shingles 
reactivation of dormant VZV from chickenpox

Question 21

measles

Answer 21

family paramyxoviruses
enveloped ssRNA helical symmetry
rash

Question 22

mumps

Answer 22

family paramyxoviruses
parotitis- inflammation of the salivary glands that brings about painful swelling
males- post pubery 20 - 30% develop orchitis
in the MMR vaccine

Question 23

rubella

Answer 23

family togaviridae
ssrna enveloped
congenital rubella - hearing loss blindness
in mmr vaccine

Question 24

papilloma virus

Answer 24

family papovaviridae 
ds dna icosahedral 
warts 
some oncogenic and cause cervical cancer 
can get vaccine for girls 14+

Question 25

new virus dieases

Answer 25

HIV Ebola (filovirus) Zika bird flupassed barrier from animals and bird (zoonoses)