VIRAL AND PRION PATHOGENS

Question 1

Herpes Virus

Answer 1

double stranded enveloped DNA virus: 9 types infect humans

Question 2

Herpes simplex 1

Answer 2

HSV-1 –> cold sores

80% uk experience this

Question 3

Herpes simplex 2

Answer 3

HSV-2 –> Genital herpes
10-20% uk had this
direct skin transmission/ vesicle fluid
can lead to meningitis and neonatal herpes –> severe disseminated viremia after verticle transmission

Question 4

Varicella zoster virus (herpes)

Answer 4

1) Chichen pox. 90% uk had chicken pox by 20
-widespred vesicular rash. more common complications in adults / pregnant
2) shingles/ herpes zoster
reactivation in dorsal root ganglion –> dermatomal rash and pain. occurs in run-down / immunosupressed

respiratory droplet transmission

Question 5

Epstein barr (herpes) 
'glandular fever' or 'infectious mononucleosis'

Answer 5

90% in uk affected by 25- 50% of this before 5yrs
virus shed in saliva and genital secretions
- infectious mononucleosis (is its own clinical syndrome) but this is the cause majority of the time (the rest is cytomegalyvirus).
-soar throat, fever, lymphadenopathy

Question 6

Cytomegalovirus (herpes)

Answer 6

• % prevalence by age eg 20% by 20 had it
• transmitted by saliva or genital secretions
• can cause infectious mononucleosis
• mothers with this during pregnancy may deliver babies with deafness/microcephaly etc
• can be transmitted by affected transplant organ or patients with AIDS get it

Question 7

Rhinovirus (respiratory virus)

Answer 7

‘common cold’ worldwide

transmitted by aerosolisation of resp. secretions and nose droplets

Question 8

Influenza (respiratory virus)

Answer 8

Influenza A, B, C
A regularly mutates where as B and C more stable
transmitted by aerosolisation of resp. secretions
fever, malaise, cough
- post influenza = bacterial lung infection

Question 9

respiratory syncytial virus (respiratory virus)

Answer 9

commonest in young children 70% affected

can cause bronchiolitis in children under 2

Question 10

HIV human immundeficiency virus

Answer 10

-70% in subsaharan africa
-virus in blood- genital secretions, breast milk
transmitted vertically, sexually, needlestick
low CD4 T cell count
–> AIDS

Question 11

Hepatitis

Answer 11

5 primary hepatotropic viruss identified ABCDE

Question 12

Hepatitis A

Answer 12

In low socioeconomic countries where its endemic- 90% of children under 5 have been affected

• faceo-oral transmission
• causes nausea, myalgia, arthralgia, and then jaundice
• asymptomatic children, symptomatic adults

Question 13

Hepatitis E

Answer 13

• endemic in asia and africa: contaminated water
• peak incidene is 15-35 yrs
• faceo-oral transmission
• high mortality in affected pregnant women
• most asymptomatic
• PIGS and undercooked meat

Question 14

Hepatits B

Answer 14

• vertical, sexual and parenteral
• younger you are, greater risk of it becoming chronic
• -> chronic hepatits –> hepatocellular carcinoma

Question 15

Hepatitis C

Answer 15

• In uk 50% IVDU have hep C
• transmission is ivdu, needlestick injury, vertical and sometimes sexual
• 85% develop chronic infection –> carcinoma

Question 16

Norovirus

Answer 16

• ssRNA virus (vomiting dominant feature)
• 90% adults been affected at some point
• 1 year immunity
• point source outbreaks
• ingested/ inhailation of vomit particles

Question 17

Rotavirus

Answer 17

dsRNA virus
most children affected before 3, 1st infection most severe
- faeco-oral transmission via contaminated food /water
- fever, vomit, watery diarrhoea

Question 18

Enterovirus

Answer 18

• 75% in under 15’s
• enteric transmission as replicates in gut –> lymph nodes –> viraemia
• fever rash syndromes in children or viral meningitis

Question 19

Parovirus

Answer 19

“slapped cheek syndrome”

• droplet transmission
• infects erythrocyte proginator cells –> transient anaemia
• infection in pregnancy = 10% fetal loss in first 20 weeks

Question 20

nvCJD

new variant creutzfeld-Jakob disease

Answer 20

prion pathogen

- directly linked to bovine spongiform encephalopathy from consumption of infected beef.