Herpes Flashcards

1
Q

What is the structure of herpes viruses?

A

ds DNA virus (low mutation rate)

Enveloped (doesn’t survive well in environment)

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2
Q

How is CMV transmitted?

A

person to person/via infected fomites

Intrauterine

Perinatal: present in cervicovag secretions

Postnatal: breast feeding, daycare, saliva, urine

Blood transfusion

Organ transplantation

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3
Q

How does CMV pathogenesis occur?

A

Infects endothelial cells of GU, upper GI, respiratory tract

Then infects leukocytes & spreads to multiple tissues

Can then become symptomatic disease, asymptomatic infection, or latent infection

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4
Q

Where is the latent CMV reservoir?

A

Myelomonocytic stem cells

Monocytes

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5
Q

What determines whether patienst have asymptomatic infection or symptomatic disease by CMV?

A

Usually asmytomatic, except in immunocmopromised patients with impaired T cell immunity

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6
Q

What are the three common manifestations of symptomatic CMV infection?

A

Infectious mononucleosis

Congenital CMV infection

CMV infection in immunocompromised host (solid organ transplantation, bone marrow transplantation, HIV/AIDS)

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7
Q

What are the symptoms of infectious mono caused by CMV?

A

Fever, hepatomegaly, lymphadenopathy, malaise, fatigue, splenomegaly, pharyngitis, rash

Lab findings: atypical lymphocytes, lymphocytosis, mild thrombocytopenia, CMV antibodies, heterophile antibodies

CMV is responsible for about 8% of IM cases; EBV is the other common cause

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8
Q

What are the symptoms of congenital CMV infection?

A

Hepatosplenomegaly, lymphadenopathy, resp distress, blueberry muffin rash, microcephaly, brain damage –> retardation, seizurse, deafness, blindness

Elevated LFT (liver function tests), thrombocytopenia, pneumonitis, CMV in body fluids

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9
Q

What are common manifestations of CMV diseases in immunocompromised host?

A

Fever, hepatitis, retinitis, pneumonitis, immunosuppression, myelosuppression, encephalopathy, colitis, rejection, graft v host disease

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10
Q

What common disease might be associated with CMV infection?

A

Atherosclerosis

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11
Q

How is CMV diagnosed?

A

Serology– IgG and IgM (note that IgM usually indicates a new infection, but in CMV even reactivations lead to an increase in IgM)

Virus isolation, pp65 antigen detection in blood, CMV DNA PCR

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12
Q

What is the treatment for CMV?

Who should get treatment?

A

Ganciclovir

Valganciclovir

Foscarnet

Cidofovir

All are viral DNA polymerase inhibtors

Used to treat immunocompromsed host

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13
Q

How is HSV transmitted?

A

Person to person

Intrauterine = rare

Perinatal

Postnatal: skin/mucous membrane contact/viral shedding in saliva, oro-facial lesions

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14
Q

Which strain is more common in oral cavity? GU tract?

A

HSV-1 in oral cavity

HSV-2 in GU tract

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15
Q

What are the 3 types of infections that HSV can cause?

A

Primary infection: virus replicates in skin & mucous membranes –> enters nerve endings –> retrograde transport to sensory ganglia –> replication here –> anterograde transport back to mucosal and cutanous sites –> can be released from lesions/ continue to replicate here

Latent infection: reversible interruption of the virus replication cycle in sensory neurons

Reactivation of latent infection: probably due to changes in host; leads to recurrent infections

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16
Q

Why are herpes lesions painful?

A

Bc they replicate in sensory neurons– causes pain!

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17
Q

What are common clinical illnesses caused by HSV infection?

Less common?

A

HSV 1:

  • *gingivostomatitis** (fever, oral pain, difficulty swallowing, vesicular lesions throughout oral cavity)
  • *pharyngitis** (fever, looks like strep, EBV)
  • *labialis** (cold sores)

HSV 1 or 2:

  • *herpes genitalis** (painful genital ulcers)
  • *neonatal herpes** (vesiculoulcerative lesions on skin, eyes mouth, encephalitis, or disseminated infection)

Less common: encephalitis, keratitis, retinitis, gladiatorim (wrestler’s herpes), herpes whitlow (finger), eczema, disseminated herpes, erythema multiforme, bells palsy,

Possibly schizophrenia, alzheimer’s

18
Q

How is HSV infection diagnosed?

A

IgG, IgM

Virus isolation

Antigen detection

DNA PCR

Clinical diagnoses= unreliable

19
Q

How do you treat HSV?

A

Oral acyclovir, valacycolvir (its prodrug), or famciclovir (penciclovir prodrug)

Topical acyclovir/penciclovir

IV Acyclovir

** these drugs are very safe. all are viral DNA pol inhibitors

20
Q

How can you prevent herpes infection- neonatal? Genital?

A

Neonatal: C-section

Genital: condoms, valacyclovir by infected partner

21
Q

What are the 3 categories of herpes infections? Features? Examples?

A

Alpha: short replication cycle, variable host range, latent in sensory neurones
HSV1, 2, VZV

Beta: long reproductive cycle, narrow host range, latent in lymphoid cells & others
CMV, HSV6, HSV7

Gamma: narrow host range, latent in lymphoid cells, associated with tumors
EBV, HSV8= KSH

22
Q

What diseases does VSV cause?

A

Varicella= chicken pox

Zoster = shingles

23
Q

What type of rash is VSV?

A

Vesicular

Highly infectious

24
Q

How does VSV spread in cells?

A

Cell to cell OR from free enveloped particle

This is important bc it can remain intracellular and still spread – antibodies can’t reach it, making cellular immunity critical for host defense against these viruses

25
What is the structure of herpes viruses?
Enveloped Icosahedral capsid DNA genome- ds
26
Where does VSV get its final envelope in the cell?
The transgolgi network
27
What is varicella?
Chicken pox- vesicular rash, sheds contagious virus particles which can infect another person via airbourne route
28
What is zoster?
Shingles - reactivation of VSV after its been latent post- varicella infection Presents as vesicular rash, dermatomal distribution, doesn't cross the midline. Rash is infectious Happens in the elderly or immunocompromised
29
When can VSV be dangerous i.e. which people?
Congenital infection-- when mom gets it during pregnancy; affects many organ systems, baby often dies In immunocompromised: more severe illness, can be fatal
30
What happens to make VSV latent?
Stays in the dorsal root ganglia Expresses only a few genes Not "lytic"
31
How can you diagnose VSV?
immunofluorescence on a smear of the vesicular fluid PCR of vesicular fluid Culture
32
How can you prevent VSV?
Vaccine: live attenuated vaccine It's the only herpes virus for which there is a vaccine
33
How can you treat VSV? Who should get treatment?
Acyclovir-- requires higher does than for HSV; not that it works best for HSV-1\>HSV-2\>VSV SE include Gi symptoms, neuro symptoms, bone marrow suppression
34
What cancer is associated with EBV?
Burkitt's lymphoma Think: E**_B_**V infects **_B_** cells and causes **_B_**urkitt's
35
What disease is caused by EBV? Symptoms? Treatment?
**Infects B cells** and causes **infectious mononucleosis**, nasopharyngeal carcinoma, lymphoma (including Burkitt's), oral hairy leukoplakia, post-transplant lympho-proliferative disease Latency develops in memory B cells after mono
36
What are the symptoms of infectious mono?
Fever, lymphadenopathy, hepatosplenomegaly, exudative pharyngitis, fatigue, rash after treatment with ampicillin
37
How do you diagnose infectious mono?
Serology
38
What is roseola?
Acute illness in infants - rash, fever, seizures; latent in CNS
39
What is herpes virus 8?
Closely related to EBV - gamma virus Causes Kaposi's sarcoma in the elderly/HIV infected
40
Which herpes infections cause congenital illness? Neonatal?
Congenital = **CMV**, VSV Neonatal = **HSV**, VSV \*\* VSV can do both