DNA Viruses Flashcards Preview

Foundations of Disease and Therapy > DNA Viruses > Flashcards

Flashcards in DNA Viruses Deck (85):
1

What's the only SS DNA virus?

Parvovirus

2

What is the important Parvovirus?

B19

3

Describe the proteins expressed by DNA viruses and the order they are expressed in

1) Interferons and proteins involved in immune evasion

2) Proteins that induce cell cycle progression (exception: Pox because it's in cytoplasm and Parvo because it's too small)

3) Structural proteins necessary to build new viral particles

4

Primary Herpes Infection

Usually the worst disease attack (if it's symptomatic); instead of a single lesion there will be multiple 

5

Treatment for CMV

Gancyclovir 

6

Name the naked DNA viruses

PAPP Parvovirus Adenovirus Papillomavirus Polyomavirus

7

Tropism for adenovirus

mucosal epithelium (primary), lymphoid, mesenchymal

8

Second Line Antiviral drugs

These drugs do not require phosphorylation; they carry higher toxicity to host however. They include Cidofovir and Foscarnet 

9

Describe the stability of Enveloped vs Naked viruses

Naked viruses are more capable of persisting in the environment and are resistant to chemical inactivation - more likely to lead to epidemic outbreaks

10

How can HSV-1 lead to Corneal Blindness and Encephaly? 

Virus is latent in Trigeminal Ganglia, so if virus goes down V1 it can reach the eye. Alternatively, if the virus goes backwards along the nerve it can reach the Temporal Lobe of brain (usually only occurs in people who get many outbreaks a year) 

11

Describe prevalence of CMV

CMV is widely dispursed throughout the population, and the vast majority of people are infected but remain asymptomatic. Most people get it during perinatal period or during reproductive years

12

Molluscum Bodies

Acidophilic inclusions seen in epidermis due to an accumulation of virons of Pox virus 

13

The worse disease associated with Gamma Herpes viruses is what?

Their latency phase - Cancer 

14

Polyoma Viruses 

  1. SV 40 
  2. JC Virus
  3. BK Virus
  4. Merkel Cell Virus

15

Where do JC and BK viruses remain latent?

Kidney, lymphocytes, and brain

16

How Alpha herpes viruses evade immune system during latency phase

They produce NO PROTEIN during latency phase; only a small intron of RNA is expressed called the LAT Transcript

17

Name the Alpha Herpes Viruses

HSV 1, HSV 2, VZV

18

Diseases associated with HSV-2

  1. Genital infection
  2. Oral infection
  3. Congenital Herpes in Neonate (bad)

19

What DNA Viruses have circular DNA?

Papilloma Polyoma Hepadna

20

Replication Machinery encoded by DNA viruses

1) DNA-Dependent-DNA Polymerase

2) Thymidine Kinase

 

Hepadna encodes Reverse Transcriptase

21

Why do we care about the site of viral replication?

We know that if we see intranuclear inclusions it's likely a DNA virus (exception: Pox), and if we see cytoplasmic inclusions it's likely an RNA virus (exception: Influenza and Retroviruses)

22

Trophism of Varicella Zoster Virus

Immune Cells and Neurons, epithelial cells, T cells

23

Diagnostic important of Syncytia

If multi-nucleated giant cells are present it indicates the virus is enveloped

24

Name the Gamma Herpes viruses

EBV, HHV 8

25

Drugs that target DNA-Dependent-DNA-Polymerase

Foscarnet and Cidofivir

26

What do Alpha and Beta Herpes viruses have in common?

Their active replication stage is associated with disease

27

What DNA virus has a pleomorphic/filamentous shape?

Hepadnavirus

28

Transmission of adenovirus and incubation time

Mainly fecal-oral, also Respiratory

incubation of 5-9 days

29

Complications of congenital CMV

  1. Number one cause of viral birth defects
  2. Microcephaly and Hearing loss are main problems
  3. Periventricular calcifications 
  4. Also Jaundice, retinitis, blueberry muffin rash, CNS damage
  5. Hydrops fetalis 

30

Transmission of Parvovirus

Aerosol or Transplacental

31

Herpes Gladiatorum

Herpes infection that's common on the neck of wrestlers 

32

Describe Monkey B Virus

It's an alpha herpes virus that typically infects monkeys but is asymptomatic in them. When it infects humans due to scratches or bites, it leads to early flu-like symptoms, then progresses to neurological symtoms such as paresthesia, disorentiation, dysphagia, ascending paralysis, encephomyelitis, coma, and DEATH

33

Do antiviral drugs work on latent viruses?

NO - they require ACTIVE viral replication 

34

What is the significance of the extremely high prevalence rate of DNA viruses in terms of diagnosis?

Serology testing is useless; must test for viral proteins

35

Name the Beta Herpes Viruses

CMV, HHV 6, HHV 7

36

Diseases associated with HSV-1

  1. Cold Sores 
  2. Ocular Infections - leading cause of ocular blindness
  3. HSV Temporal Lobe Encephalitis 

37

Main difference between HSV-1 and HSV-2 inections 

HSV-1 infections typically recur about once a year; HSV-2 infections recur multiple times a year 

38

How are HSV-1 and HSV-2 diagnosed?

  1. HSV-1 and HSV-2 are distinguished by ELISA antibody type specific assays against Glycoprotein G (most rapid method, especially for possible encephalitis case) 
  2. Tzank Test is the old method

39

Reactivation Phase of Herpes Virus

  1. Recrudescent Disease - single cold sore (because only one neuron reactivated)
  2. Asymptomatic Shedding - the virus is active but the patient sees no symptoms; this is how most transmission occurs 

40

Disease caused by BK virus

Hemorrhagic Cystitis in organ transplant patients 

41

Where does HHV-2 remain latent

Sacral Ganglia

42

Diseases caused by CMV

  1. Mononucleosis (adolescents)
  2. Severe Congenital Infections (hearing loss, periventricular calcifications, blueberry muffin rash, hydrops fetalis)
  3. Esophagitis with linear ulcerations
  4. CMV Colitis with ulcerated walls
  5. CMV Retinitis (CD4 Count < 50)
  6. CMV Pneumonia/ severe systemic infection (recent organ transplant)

43

Guarnieri Bodies

Basophilic sites of DNA replication within cytoplasm of cells infected with a Pox virus 

44

Diseases caused by HHV-6 and HHV-7

  1. Roseola Infantum (Sixth Disease)
  2. Can cause febrile seizures and encephalitis 
  3.  

45

Tzank Test

Looks for multi-nucleated giant cells (Syncytia) which indicates the virus has an envelope. This can be coupled with intranuclear/cytoplasmic inclusion tests to further narrow down which virus you might be dealing with. Most important for new viruses nowadays since we have more specific tests for current ones

46

Generalized Vaccinia

Because Smallpox vaccine is a live-attenuated virus, 1:5000 may get vaccinia. This is only a problem for neonates and immunocompromised. Right now, only CDC workers and Military are at risk. The CDC has immunoglobins to treat this 

47

Diseases caused by adenovirus

1) Acute Respiratory Disease (ARD) - seen in military recruits

2) Pneumonia 

3) Sporadic follicular Conjunctivitis - benign conjunctivitis and most common eye infection

4) Epidemic keratoconjunctivitis - pink eye; can spread in public pools

5) Gastroenteritis - second most common cause of infantile viral diarrhea; people can shed this virus in stool months after infection

48

Cancerous protein made Polyoma viruses 

Large T (LgT)

49

Define Syncytia

Property of enveloped viruses that allows them to merge neighboring cells together to form multi-nucleated giant cells

50

Herpes Virus pathogenesis 

  1. Primary Lyctic Infection occurs because virus gains access to body through mucosal breaks
  2. During latent infection, virus persists in ganglia (immunoprivileged)
  3. If a stress occurs, the virus reactivates - only ONE neuron gets activated, so you usually only get one cold sore 

51

Describe vaccines availble for VZV

  1. Live-attenuated VZV vaccine given to children to prevent chicken pox
  2. Zostavax - Live-attenuated vaccine with 10x more concentrated dose given to adults over age 60 to invoke a stronger T Cell response in order to prevent shingles/neuralgia

52

Tropism of Parvovirus

Epithelial cells in S Phase of cell cycle, Erythroid progenitor cells, Endothelial cells of Blood vessels

53

Diagnosis of JC virus/PML

Multiple non-ring-enhancing lesions in brain of immunocompromised patient 

54

How are HHV-6 (a and b) and HHV-7 transmitted?

  • HHV-6b is transmitted in saliva
  • HHV-6a is transmitted sexually
  • HHV-7 is transmitted in breast milk

55

Disease caused by JC Virus

Progressive Multifocal Leukoencephalopathy 

56

What DNA virus lacks an icosahedral structure?

Poxvirus; it is a multi-enveloped Ovoid Block (complex)

57

Trophism of Herpes Simplex Virus

Neurons and epithelial cells 

58

Where do EBV and HHV-8 (Kaposi's Sarcoma) remain latent?

B cells 

59

Hemorrhagic Cystitis

Caused by BK virus; diffuse inflammation of the bladder leading to dysuria, hematuria, and hemorrhage. Associated with bone marrow transplant patients 

60

Molluscum Contagiosum

Only Pox virus we have to worry about; usually only occurs in immunocompromised 

61

Transmissibility of VZV

Aerosol transmission so highly contageous 

62

What enzyme activates nucleoside derivatives in Alpha Herpes Viruses? CMV?

  • Alpha Herpes Viruses: Thymadine Kinase
  • CMV: Phosphotransferase 

63

Where do HHV-6 and HHV-7 remain latent? 

T cells 

64

Trophism of Cytomealovirus

Monocytes 

65

What is a potential problem with immune-modulating monoclonal antibodies?

They can lead to a reactivation of JC virus which results in Progressive Multifocal Leukoencephalopathy 

66

Does B19 have a vaccine?

No, but most people have had it and have antibodies for it

67

Cancerous proteins made by papilloma viruses

E6 and E7 transforming proteins 

68

What is unique about HHV-6?

It can be integrated chromosomally and inherited genetically 

69

Envelope of Pox viruses

Pox viruses have two envelopes associated with one virus. Both forms are infectious. The body has to neutralize both versions of envelopes, and vaccines must target both forms

70

Pathogenicity of Parvovirus and special requirements

Direct cell damage by viremia as well as humoral immune response.

Must invade actively dividing cells since it does not encode proteins that encourage cell division; Alternatively it can co-infect with another DNA virus that has this machinery

71

What are the only Herpes viruses that do not infect a majority of the population

Kaposi's Sarcoma (HHV 8) and HSV-2

72

Other diseases/co-infections associated with Herpes infections

  1. HSV-2 is associated with HIV infection
  2. HSV-1 is associated with Alzheimer's 

73

Complication of Shingles

Post Herpetic Neuralgia - extremely painful due to death of neurons. Unlike HSV, when VZV reactivates many neurons are affected and you can get a lot of neuronal death

74

Diagnosis of BK Nephropathy 

Characteristic viral inclusions in biopsy materials; nuclear enlargement with "smudgy" or "ground glass" appearance 

75

Where does VZV remain latent

Dorsal Root Ganglia

76

How to nucleoside antivirals work?

They must be phosphorylated in the cell, and this only happens in actively dividing cells. Then they have very high affinity for Viral Polymerase 

77

Diagnosis of CMV

  1. Cytomegaly on histology with "owl-eyes" appearance
  2. Monospot test if patient presents with mono; if test is negative the virus causing mono is CMV
  3. IgM antibodies indicate primary acute infection

78

Pathogenicity of adenovirus

Very stable in the environment and resistant to chemical/physical agents (including chlorinated pools) as well as adverse pH. Causes direct cell damage via replication with strong cellular immune response

79

Periventricular Calcifications on neonate indicate what?

Congenital CMV infection 

80

Where does HHV-1 remain latent

Trigeminal Ganglia

81

Where does CMV remain latent

hematopoietic progenitor cells/monocytes

82

Main mechanisms of viral drug resistance 

  1. Alteration in Thymidine Kinase/Phosphotransferase (valacyclovir and famciclovir)
  2. Alteration in DNA Polymerase (valacyclovir, famiciclovir, acyclovir, adn foscarnet) 

83

What do Beta and Gamma herpes viruses have in common?

Their latencey stage is in leukocytic immune cells 

84

Herpes Whitlow

Usually occurs on doctors and dentists from treating patients' mouths who have an active Herpes infection without wearing gloves; they get a Herpes infection on their thumb 

85

Diseases caused by B19

Mneumonic: PARvo

Pregnancy-associated hydrops fetalis

Aplastic anemia and Arthritis

Rash (erythema infectiosum)

 

1) Fifth disease (Erythema infectiosum) - "slapped cheek rash"

2) Hydrops fetalis - causes severe hypoxia in fetus due to anemia

3) Persistent infection in Immunocompromised

4) Aplastic Crisis and Relapsing Chronic Anemia in those with RBC disorders like Sickle Cell