Lecture 3 Herpes viruses only Flashcards Preview

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Flashcards in Lecture 3 Herpes viruses only Deck (21):
1

What is lecture 3 about?

Herpes and hepatitis in oral health

2

How many different herpesviruses discussed in lecture what are they? 

  1. Herpes simplex V. type 1 (HSV-1)
  2. HSV-2 
  3. Varicella zoster virus (VZV)
  4. Epstein Barr Virus (EBV)
  5. Cytomegalovirus (CMV)
  6. Human Herpesvirus 6 (HHV6)
  7. HHV7
  8. HHv8/ KSHV

3

Is herpes species-specific or can be transmitted between species? 

Herpes is specific to each species, for example, humans have their own herpes virus,

  • Equine Herpesvirus is a problem for horses 
  • Salmonid are problems for fish farms 

4

Which ones are the neurotropic herpesviruses? 

  • HSV-1
  • HSV-2
  • VZV

 

5

How do HSV-1 and 2 infect? what do they infect? 

 

HSV1 and 2 only infect proliferating epithelial cells. That's why having a cut can increase the chances of contracting it since the virus can access the deep proliferating layer of the epidermis. 

  • It's neurotropic because it uses an intra axonal transport method to reach an area where it goes through its latency cycle
    • Reactivation can occur afterwards due to immunological impairments and that leads to reemergence of the disease 

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6

What are the manifestations of HSV-1?

 

  • The majority don't reactivate, usually goes to a ganglion near oral cavity and stay there and even reemergence is not bad. 
    • The majority might not even attract attention as they could seem asymptomatic
  • The biggest issue with HSV 1 is that it could get to the cornea and leads to Keratitis and that is 2nd only to trauma as a cause of corneal blindness. 
  • HSV1 can also manifest into hepatic whitlow and that manifests in the thumb
    • Used to be a big issue for hygienists and dentists before utilization of gloves.

 

7

What is the primary problem with HSV-2? 

HSV-2 is a genital infection that has symptoms of growing clusters or sores full of virus practicals that can transfer from one person to another 

  • One of the biggest manifestations is if the mother is infected and she is having a flare of herpes during birth it can be contracted to the baby and that leads to a systemic neonatal herpes simplex type 2 where the whole body is infested with these sores and virus particles 
  • The HSV virus would disseminate to different organs and leads:
    • Death
    • Mental Retardation or neurological disability 
    • 80% mortality if the antiviral is not used. 

 

8

What are the rare but fatal manifestation of HSV1 and HSV2? 

 

  • HSV 1
    • Manifests into herpes simplex encephalitis in adults and young children
      • Very rare but very dangerous 
  • HSV-2 
    • Manifests into herpes simplex meningitis (Not serious) but usually due to HSV-2 from those with genital infections 

9

What are the common herpes Antivirals? How effective are they? 

  • Acyclovir
  • Valacyclovir 
  • They're very effective and they work by halting the DNA replication of the virus of the herpes lytic cycle 

10

Why is acyclovir very effective in stopping the manifestation of the herpes virus? 

  • Acyclovir is very similar in shape as the nucleoside Deoxyguanosine and it infiltrates the chain they the polymerase is reading it results in the termination of the replication and inhibits the polymerase 
  • This is so specific that it doesn't activate with any cell replication but the herpes polymerase which makes it extremely efficient and low risk 
  • Acyclovir only works with HSV1, 2 and VSV

 

11

What is VZV and what are the manifestations? what is the difference between Primary infection and secondary infection? 

  • ITs the varicella-zoster virus causes chicken pox and shingles. 
    • Primary infection leads to primary viremia and then the virus replicates in the liver and other organs and leads to secondary viremia
    • secondary viremia leads to skin appearance change and vesicular rash. 
  • The chicken pox has the pox marks on the skin and they're full of the virus particles so they can transfer via contact and if they dry they can evaporate and contract via inhalation.
  • If you get it once you cant get it a second time 

 

12

What is the problem with VZV latency and reactivation?

  • Usually, the Primary infection of chicken pox is very mild and doesn't cause severe problems
  • The reactivation, however, can lead to shingles and that is very problematic because the virus will transit down the peripheral nerve and lead to infecting the dermal areas where it was initiated this leads to Dermatomes 

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13

What are the VZV intervention strategies we have now? 

  • Antivirals 
    • Acyclovir and Valacyclovir
  • Effective vaccines which is an attenuated vaccine 
    • Varivax is given to children 
      • Zostavax is given to 60> adults to stop reemergence
        •  

14

What are the lymphotropic herpesviruses? 

  • They're viruses that infect cells of the lymphatic system: T cells and B cells, monocytes, macrophages and dendritic cells
  • EBV
  • CMV
  • HHV6
  • HHV7
  • HHv8

 

15

  • What are some cancer manifestation of EBV?

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16

Since most people already have EBV, how can it be dangerous? 

  • its dangerous with immunocompromised individuals
    • AIDS can lead to oral hairy leukoplakia 
    • Post transport lymph-proliferative disease can also is due to EBV

 

17

  • What is CMV?
  • Whats the population at risk?
  • Its a major cause of what?
  • Whats the drug of choice?
  • Is there a vaccine?

 

  • Cytomegalovirus
  • Embryos, neonates and immunocompromised individuals are at risk
  • A major cause of deafness, hearing loss in children 
  • Ganciclovir is the current drug of choice 
  • No vaccine but some candidates are being tested 

 

18

  • What does HHV6 Cause? What does it infect?
  • What does HHV7 cause?
  • What do both of them may be associated with? 

 

  • HHV6 causes roseola and exanthem subitum in children.
    • A neurotropic and lymphoproliferative disease can be a result 
    • Can infect both T and B lymphocytes 
  • HHV7 
    • Causes roseola and infection of T cells only
  • Both may be associated with Transplant diseases 

 

19

  • What is HHV8 leads to? 
    • Whats the population that is most at risk?
    • What disease is associated with the virus? 

 

  • Its a newly identified herpes virus 
  • Its an infectious agent responsible for Kaposi sarcoma 
    • Kaposi sarcoma is the most common neoplasm in homosexual and bisexual men. 
  • HHV8 is associated with Castleman's disease 
    • Primary effusion lymphoma 
    • Body cavity lymphoma

 

20

  • What is the summary of herpes virus
  • Are they ubiquitous? 
  • The majority are carriers of which ones?
    • Most infections are acquired at what stage? 

  • Herpes are ubiquitous 
  • most people carry all of them except for HSV2 and HHV8 
  • Most infections reacquired in childhood except for HSV2 and HH V8 

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