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Flashcards in Herpesviruses Deck (104)
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1
Q

What are herpesviruses?

A

Large enveloped dsDNA viruses

2
Q

How long do herpesvirus infections last?

A

Lifelong

3
Q

What is the pattern of a herpesvirus infection?

A

Latency following the acute primary episodes and relapses occuring later in life when the individual becomes immunosuppressed

4
Q

How many types of herpesvirus are there?

A

8

5
Q

What are the classes of herpesviruses?

A
  • α-herpesviruses
  • ß-herpesviruses
  • γ-herpesviruses
6
Q

What are the features of class α-herpesviruses?

A

Fast growing cytolytic viruses that establish latent infection in sensory ganglia

7
Q

What are the α-herpesviruses?

A
  • HSV1
  • HSV2
  • VZV
8
Q

What are the features of class ß-herpesviruses?

A

Slow growing viruses that lie latent in secretary glands and in the kidneys, and have long replication cyles

9
Q

What are the ß-herpesviruses?

A
  • CMV
  • HHV6
  • HHV7
10
Q

What are the features of class γ-herpesviruses?

A

Latency occurs in lymphoid tissues

11
Q

What are the γ-herpesviruses?

A
  • EBV
  • Karposi’s Sarcoma Virus
12
Q

What type of envelope do herpes viruses possess?

A

Lipid

13
Q

What surface do herpes viruses prefer?

A

Moist mucosal surfaces

14
Q

Where are herpes viruses commonly secreted?

A

By oral and genital secretions

15
Q

What is oral transmission of the herpes virus associated with?

A

Primary infection at an early age

16
Q

When does genital tranmission of the herpes virus cause infection?

A

At a later period in life

17
Q

Does oral or genital transmission of the herpes virus have a higher seroprevelance?

A

Oral

18
Q

What are herpes viruses able to do with their genetic information?

A

Integrate it into host cells

19
Q

What happens once herpes viruses’ have integrated their genetic information into host cells?

A

They remain as latent infections, and can occassionally reactivate their genetic material

20
Q

What happens once herpes viruses’ have reactivated the genetic material they had previously integrated into host cells?

A
  • Causes clinical illness
  • Spreads to other susceptible individuals
21
Q

What can some herpes viruses exhibit?

A

Oncogenic potential

22
Q

How severe are primary infections of herpes?

A

Usually mild or subclinical

23
Q

How severe are subsequent presentations of herpes?

A

Can have the potential to cause serious life-threatening illness

24
Q

Who is especially at risk of subsequent life threatening presentations of herpes?

A

Immunosuppressed individuals

25
Q

What is HHV 1 known as?

A

HSV1

26
Q

What is HHV 2 known as?

A

HSV2

27
Q

How are HSV1 and HSV2 spread?

A

By direct, person-to-person contact

28
Q

Is HSV1 or HSV2 more common from oral transmission?

A

HSV1

29
Q

Who is HSV1 common in?

A

Young children

30
Q

What will HSV1 infection result in?

A

Asymptomatic response

31
Q

What can HSV1 cause on reactivation?

A
  • ‘Cold sores’
  • Dendritic ulcers
  • Herpetic whitlow in traumatised skin
  • Fatal encephalitis
32
Q

When does HSV1 reactivate as ‘cold sores’?

A

In times of stress

33
Q

What are the symptoms of fatal encephalitis?

A

Personality changes and confusion

34
Q

What can maternal transmission of HSV1 during childbirth result in?

A

Neonatal herpes

35
Q

Is HSV1 or HSV2 more common from genital transmission?

A

Genital

36
Q

What does HSV1 cause?

A

Genital ulceration

37
Q

How does the recurrent infection of HSV2 differ from HSV1?

A

Milder and shorter lived

38
Q

Why are the genital ulcers caused by HSV2 important?

A

Important in the transmission of the HIV infection

39
Q

What class of herpesvirus are HSV1 and HSV2?

A

α

40
Q

Where do HSV1 and HSV2 affect on initial epithelial cell infection?

A

The ganglion

41
Q

Where do HSV1 and HSV2 viruses stay latent?

A

In the sensory neurone ganglion

42
Q

What is HSV3 known as?

A

Varicella Zoster Virus (VSV)

43
Q

How many serotypes does VSV have?

A

1

44
Q

By what route is VZV spread?

A

Aerosol

45
Q

How is VZV spread via the aerosol route?

A

The vesicles rupture to release the virus, and the VSV then spreads by aerosol spread

46
Q

Where does VZV remain latent?

A

In the sensory ganglion

47
Q

How does the primary infection of VZV appear?

A

Chicken pox

48
Q

What is the infection rate of chickenpox?

A

90%

49
Q

What happens in chickenpox?

A

Lesions and vesicular eruptions will form, which will subsequently rupture to release the VZV into the atmosphere and will heal spontaneously

50
Q

What is the outcome of chickenpox?

A

Complete resolution is normal, unless lesions become infected as a result

51
Q

What can VZV cause if its primary presentation is in adults?

A

VZV pneumonia

52
Q

Who is especially at risk of VZV pneumonia?

A

Immunocompromised individuals

53
Q

What is the prognosis of VZV pneumonia?

A

High mortality

54
Q

What does the reactivation of VZV from the sensory root ganglion cause?

A

Shingles

55
Q

What happens in shingles?

A

The virus travels down the axon of the sensory route ganglion to produce lesions in that dermatome

56
Q

What is shingles commonly triggered by?

A
  • Stress
  • Immunocompromisation
57
Q

What can shingles cause in the elderly?

A
  • Ocular damage
  • Post hepatic neuralgia
58
Q

When does primary infection of VZV commonly occur?

A

Between 4-10 years

59
Q

What does primary infection of VZV provide?

A

Lifelong immunity

60
Q

What is HHV 4 known as?

A

The Epstein Barr virus (EBV)

61
Q

What does EBV cause?

A

Infectious mononucleosis

62
Q

What class of herpesvirus is EBV?

A

γ

63
Q

How does EBV spread?

A

Via saliva

64
Q

What % of the population is EBV found in?

A

90-95%

65
Q

How does EBV gain entry?

A

Via the pharynx

66
Q

What does EBV infect once it has gained entry?

A

B lymphocytes

67
Q

What happens once EBV has infected the lymphocytes?

A

It remains latent

68
Q

How can EBV evade immune responses?

A

By inhibiting class I MHC presentation, reducing the load of class I MHC molecules by viral peptides

69
Q

What are the symptoms of EBV infection?

A
  • Malaise
  • Fever
  • Sore throat
  • Lymphadenopathy
70
Q

What properties does EBV have?

A

Oncogenic

71
Q

What cancers can be caused by EBV?

A
  • Burkitt’s lymphoma
  • Nasopharyngeal carcinoma
  • Lymphoma
72
Q

Where does EBV cause Burkitt’s lymphoma?

A

Sub-saharan Africa

73
Q

What is EBV caused Burkitt’s lymphoma in association with?

A

Malaria

74
Q

Where does EBV cause nasopharyngeal carcinoma?

A

China

75
Q

In whom does EBV cause lymphoma?

A

Immunosuppressed individuals

76
Q

How long do symptoms of EBV last?

A

Around 2 weeks

77
Q

What is treatment of EBV infection based on?

A

Mainly symptoms based

78
Q

What is HHV 5 known as?

A

Cytomegalovirus (CMV)

79
Q

How is CMV transmitted?

A
  • Vertical
  • Saliva
  • Blood
  • Sexual transmission
80
Q

What is the prevalance of CMV?

A

Around 50% of the population by 35 years

81
Q

Where des CMV remain latent?

A

In monocytes and lymphocytes

82
Q

What class of herpesvirus is CMV?

A

ß

83
Q

What is the clinical presentation of CMV?

A

Often asymptomatic or subclinical in initial infection, yet can produce mononucleosis-like symptoms in some

84
Q

When can CMV spread to neonates?

A

To the foetus before birth, or after birth

85
Q

What can CMV cause in neonates?

A
  • Serious infections
  • Later developmental defects
86
Q

What can reactivation of CMV in immunocompromised individuals cause?

A
  • Severe pneumoitis
  • Colitis
  • Retinitis
87
Q

What can retinitis develop to?

A
  • Retinal detachment
  • Blindness
88
Q

What does CMV cause on histology?

A

A ‘giant owl’ inclusion body

89
Q

By when is HHV 6 and HHV 7 found in most individuals?

A

The second year of life

90
Q

What is often the effect of HHV 6 and HHV 7 infection?

A

It is often subclinical

91
Q

How can HHV 6 and HHV 7 sometimes arise in some individuals?

A

As Rosala infantatum

92
Q

What are the symptoms of Rosala infantatum?

A

Produces rash and fever

93
Q

What class of herpesvirus are HHV 6 and HHV 7?

A

ß

94
Q

What is HHV 8 also known as?

A

Kaposi’s sarcoma virus

95
Q

How is HHV 8 transmitted?

A

Vertically, or via mucosal transmission

96
Q

How does HHV 8 initially present?

A

With mononucleosis-like symptoms

97
Q

In whom can HHV 8 reactivate?

A

Immunocompromised individuals

98
Q

How does HHV 8 present on reactivation in immunocompromised individuals?

A

As a vascularised tumour

99
Q

What causes the vascularised tumour in HHV 8 infection?

A

Excessive angiogenesis, inflammation, and proliferation

100
Q

How can the tumour in HHV 8 infection be treated?

A

Radiotherapy

101
Q

What is a HHV 8 tumour associated with?

A

HIV

102
Q

How is diagnosis of the herpesvirus made?

A

Though NAAT using specimens ffrom rashes, blood, or urine, or through serological testing

103
Q

What does treatment of herpesviruses involve?

A

Mainly supportive care, yet in severe cases anti-virals can be used

104
Q

What antivirals are used in the treatment of herpesvirsuesa?

A

Mainly ganciclovir or aciclovir