T1 - L5 VIRAL AND PRION PATHOGENS

Question 1

viruses consist of what 4 components?

Answer 1

• genome (RNA/DNA)
• capsid (protein coat)
• envelope (lipid bilayer)
• their own enzymes

Question 2

what are the 8 steps of the virus life cycle?

Answer 2

1. attachment
2. entry
3. uncoating
4. synthesis
5. assembly
6. release

Question 3

what are the 2 things that classify viruses?

Answer 3

1. genetic material
   - DNA vs RNA
   - single vs double stranded
   - positive vs negative sense
2. presence or absence of an envelope

Question 4

what type of viruses are the herpes viruses?

Answer 4

Double-stranded enveloped DNA viruses

Question 5

what are the two characteristics of herpes viruses?

Answer 5

ability to establish latency and reactivate

Question 6

which virus causes cold sores?

Answer 6

HSV-1

Question 7

which virus causes genital herpes?

Answer 7

HSV-2

Question 8

encephalitis is often associated with which virus?

Answer 8

HSV-1

Question 9

meningitis is often associated with which virus?

Answer 9

HSV-2

Question 10

what is viraemia?

Answer 10

the presence of viruses in the blood.

Question 11

how does neonatal herpes occur?

Answer 11

usually as a consequence of

vertical transmission from mother’s genital tract at delivery.

Question 12

which virus causes chicken pox?

Answer 12

primary infection of varicella zoster virus (herpes zoster)

Question 13

which virus causes shingles?

Answer 13

reactivation of varicella zoster virus (herpes zoster)

Question 14

what is the mode of transmission of varicella zoster virus?

Answer 14

• respiratory droplet
• vesicle fluid
• latency established in dorsal root ganglion

Question 15

what virus causes glandular fever/infectious mononucleosis?

Answer 15

Epstein Barr virus

Question 16

what is the mode of transmission of Epstein Barr virus?

Answer 16

Virus is shed in saliva and genital secretions – ‘kissing disease’ (glandular fever)

Question 17

what is the mode of transmission of Cytomegalovirus

?

Answer 17

• Saliva or genital secretions
• Donated blood, stem cells or organs
• Latency in monocytes / dendritic cells / myeloid progenitors [i.e. immune system]

Question 18

infants born to mothers who have Infectious mononucleosis at delivery - may suffer from what?

Answer 18

Retinitis,
deafness,
microcephaly,
hepatosplenomegaly

Question 19

what is the most common virus to cause the common cold?

Answer 19

rhinoviruses (30-50%)

Question 20

what is the transmission of rhinovirus?

Answer 20

Aerosolised respiratory secretions [cough; sneeze] and droplets from nose and eyes

Question 21

what subtype of influenza A causes swine flu?

Answer 21

H1N1

Question 22

respiratory syncytial virus

is most common in which group of people?

Answer 22

young children

Question 23

mode of transmission of respiratory syncytial virus?

Answer 23

Aerosolisation of respiratory secretions

Question 24

Bronchiolitis is caused by which virus?

Answer 24

respiratory syncytial virus

Question 25

what is the mode of transmission of HIV?

Answer 25

vertically (from mother to child) sexually needlestick

Question 26

HIV targets which cells?

Answer 26

helper T lymphocytes (CD4)

Question 27

which hepatotropic viruses are face-oral spread?

Answer 27

hep A | hep E

Question 28

which hepatotropic viruses are blood borne?

Answer 28

hep B hep C hep D

Question 29

which type of hepatotropic virus is associated with pigs, undercooked meat (especially pork)?

Answer 29

Hep E genotypes 3 and 4

Question 30

which type of hepatotropic virus is associated with contaminated water?

Answer 30

Hep E genotypes 1 and 2

Question 31

which type of hepatotropic virus is asymptomatic in children but symptomatic in 50% of adults?

Answer 31

Hep A

Question 32

which type of hepatotropic virus is associated with lower socio-economic groups, returning tourists and men who have sex with men (MSM)?

Answer 32

Hep A

Question 33

what is acute clinical hepatitis?

Answer 33

The term acute viral hepatitis often refers to infection of the liver by one of the hepatitis viruses - nausea - myalgia - arthralgia - fevers - jaundice - right upper quadrant pain

Question 34

what is Fulminant hepatitis?

Answer 34

a rare syndrome of massive necrosis of liver parenchyma and a decrease in liver size (acute yellow atrophy) that usually occurs after infection with certain hepatitis viruses

Question 35

what is the association between risk of hepatitis B chronicity and age?

Answer 35

Risk of chronicity is inversely related to age at infection | may be due to mode of transmission is parenteral/having children/being sexually active

Question 36

how would hepatitis lead to cancer?

Answer 36

chronic hepatitis → cirrhosis → hepatocellular carcinoma

Question 37

what is the mode of transmission for hepatitis C?

Answer 37

IVDU, needlestick injuries, transfusion of contaminated products (Vertical & sexual transmission is less common)

Question 38

what type of virus is norovirus?

Answer 38

ssRNA

Question 39

what type of virus is rotavirus?

Answer 39

dsRNA virus

Question 40

what is the mode of transmission of norovirus?

Answer 40

ingestion/inhalation of aerosolised vomit particles

Question 41

what is the mode of transmission of rotavirus?

Answer 41

faeco-oral via contaminated food/water and aerosolised faeces/vomit.

Question 42

which virus is a major cause of infant mortality in the developing world?

Answer 42

rotavirus

Question 43

which virus is associated with point-source outbreaks? (e.g hospitals, cruise ships, military)

Answer 43

norovirus

Question 44

what is the classic presentation of norovirus?

Answer 44

vomiting

Question 45

what is the classic presentation of rotavirus?

Answer 45

fever, vomiting and watery diarrhoea

Question 46

what time of year do enteroviruses peak?

Answer 46

summer/autumn in UK

Question 47

what type of virus are enteroviruses?

Answer 47

positive sense ssRNA

Question 48

what is the mode of transmission of enteroviruses?

Answer 48

contaminated food/water.

Question 49

where to enteroviruses replicate?

Answer 49

Replicate in gut, but do NOT cause GI symptoms [Gets into blood and causes symptoms]

Question 50

list some serotypes of enteroviruses

Answer 50

poliovirus Coxsackie A and B enterovirus echoviruses

Question 51

herpangina is associated with which enterovirus?

Answer 51

Coxsackie A [oral ulceration in top pic]

Question 52

pericarditis is associated with which enterovirus?

Answer 52

Coxsackie B [inflammation of pericardium]

Question 53

what time of year does Mumps peak?

Answer 53

winter

Question 54

what is the mode of transmission of mumps?

Answer 54

- Virus is shed in saliva and respiratory secretions | - Droplet transmission from respiratory route

Question 55

what 3 clinical syndromes can mumps lead to?

Answer 55

Acute parotitis [inflammation of parotid gland] orchitis meningitis (which can lead to meningoencephalitis and sensorineural deafness)

Question 56

what is the mode of transmission of the measles?

Answer 56

Droplet transmission from respiratory route NB: Highly infectious – environment still infectious after 2 hours

Question 57

how does primary measles present?

Answer 57

Fever, coryza, cough, conjunctivitis, Koplik’s spots on inside of cheek THEN maculopapular rash

Question 58

what is the mode of transmission of rubella? (German measles)

Answer 58

Droplet transmission from respiratory route

Question 59

what is the triad of classical presentation of congenital rubella?

Answer 59

Bilateral cataracts sensorineural deafness microcephaly

Question 60

how does primary postnatal rubella present?

Answer 60

- Mild illness, fever and maculopapular rash | - Arthralgia [achy joints] / arthritis occurs in 30% adults

Question 61

which virus is referred to as "slapped cheek syndrome" or "fifth disease"?

Answer 61

Parvovirus B19

Question 62

what time of year does Parvovirus B19 | peak?

Answer 62

late winter/early summer

Question 63

what is the mode of transmission of Parvovirus B19?

Answer 63

Droplet transmission from respiratory route

Question 64

which virus Infects and destroys erythrocyte progenitor cells – causing transient anaemia?

Answer 64

Parvovirus B19

Question 65

list 3 clinical syndromes that can happen as a consequence of Parvovirus B19?

Answer 65

- Erythema infectiosum (fever, coryza, fiery red rash to cheeks) - Transient aplastic crisi (Dyspnoea, confusion, cardiac failure) - infection in pregnancy (fatal loss/hydrops fetalis)

Question 66

what is a prion?

Answer 66

Small infectious pathogen containing protein, no nucleic acid - Prion proteins exist naturally in cells - Gene mutation leads to changes in folding pattern - As a result, prion becomes resistant to protease enzyme - Prion therefore accumulates in cell and becomes pathogenic

Question 67

how are abnormal prions transmitted?

Answer 67

- inherited (genetic defects) | - Transmitted via consumption of infected meat or exposure to infected material.

Question 68

Human prion diseases share which properties?

Answer 68

- pathologic manifestations confined largely to CNS - produce spongiform change in brain tissue - long incubation times (up to 30 yrs) - progressive and fatal

Question 69

what are symptoms of Creutzfeld-Jakob disease?

Answer 69

Progressive ataxia [unsteady gait], depression, dementia then death.

Question 70

New variant CJD is associated with the consumption of what?

Answer 70

infected beef nvCJD directly linked to BSE (bovine spongiform encephalopathy) [prion disease in cows]