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Infectious Disease: Unit 1 > Herpesviral Diseases > Flashcards

Flashcards in Herpesviral Diseases Deck (33)
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1
Q

HSV-1 (α): Shedding

A
  • In oral/genital secretions
  • Shedding in both latent and active phases
2
Q

HSV-1 (α): lytic features

A
  • Gingivostomatitis
  • Genital herpes
  • Herpetic keratitis
  • Neonatal herpes
  • Herpetic whitlow
  • Encephalitis
  • Dissemination
  • Reactivation
3
Q

HSV-1 (α): latent feature

A
  • Trigeminal ganglion
4
Q

HSV-1 (α): disease of immunocompromised

A
  • Reactivation common
  • Severe in people with defective T-cell immunity
  • Prophylactic antivirals used during chemo, etc.
  • Neonatal HSV (severe/fatal)
  • Important role for antiviral therapy
5
Q

HSV-2 (α): shedding

A
  • In genital/oral secretions
  • Shedding in both latent and active phases
6
Q

HSV-2 (α): lytic feature

A
  • Same as HSV-1:
    • Gingivostomatitis
    • Genital herpes
    • Herpetic keratitis
    • Neonatal herpes
    • Herpetic whitlow
    • Encephalitis
    • Dissemination
    • Reactivation
7
Q

HSV-2 (α): latent feature

A
  • Sacral ganglion
8
Q

HSV-2 (α): disease of immunocompromised

A
  • Reactivation common
  • Severe in people with defective T-cell immunity
  • Prophylactic antivirals used during chemo
  • Neonatal HSV (severe/fatal)
  • Important role for antiviral therapy
9
Q

VZV (α): shedding

A
  • Varicella: shed before rash erupts via respiratory drops
  • Zoster: by fomites
10
Q

VZV (α): lytic feature

A
  • Varicella: chicken pox
    • Fever, malaise, headache, dew drop on rose petal rash
  • Zoster: shingles
    • Prodrome, dermatomal vesicles, unilateral, post-herpetic neuralgia
11
Q

VZV (α): latent feature

A
  • Any ganglion
  • Usually dorsal root (spinal) ganglion
12
Q

VZV (α): diseases in immunocompromised

A
  • Bacterial superinfection
  • Severe infection in immunocompromised children and adults
  • T-cell mediated immunity decrease provides opportunity for VZV to progress to shingles
13
Q

CMV (β): shedding

A
  • Pharynx shedding
  • Infection can occur at any age
    • In utero through placenta
    • Shedding during delivery or in neonatal period
    • From childhood playmates
    • From sexual partners
    • From blood products and transplanted tissue
14
Q

CMV (β): lytic feature

A
  • Mono-like syndrome in adults
  • Congenital disease has multi-system disease with:
    • Hepatitis
    • Thrombocytopenia
    • Small brain
    • Seizure
    • Chance of hearing loss
15
Q

CMV (β): latent feature

A
  • Latency in myeloid precursors, endothelial cells, possibly others
16
Q

CMV (β): disease in immunocompromised

A
  • T-cell mediated immunity decrease (with age) provides opportunity for CMV
  • Disease in newborn:
    • Maternal Ab leads to asymptomatic infection
  • Primary infection in mom during pregnancy –> severe disease (3-5% of the time)
17
Q

HHV 6 + 7 (β): shedding

A
  • Saliva shedding
  • Sometimes nearly constant
18
Q

HHV 6 + 7 (β): lytic feature

A
  • Exanthema subitum
    • aka roseola infantum
  • Presents as:
    • Lethargy, irritability, fever
    • Injection of pharynx, tonsils, tympanic membranes
  • Possible diarrhea, vomiting, adenopathy
  • Diffuse maculopapular rash as fever subsides
  • Mononucleosis syndrome possible
19
Q

HHV 6 + 7 (β): latent feature

A
  • Viruses infect tissues, probably epithelial cells, in back of throat
  • Circulating B and T cells then become infected –> spread virus throughout rest of body to cause characteristic illness
20
Q

HHV 6 + 7 (β): disease in immunocompromised

A
  • Defective T-cell mediated immunity: multiorgan disease
    • Pneumonia, colitis, hepatitis, bone marrow suppression, colitis, encephalitis
  • Disease in infant
    • 20% of all fever in this age
    • Including febrile seizure
21
Q

HHV 4 (ɣ) aka EBV: shedding

A
  • Salivary shedding
    • > 95% of adults have antibody
  • Shedding is common and often
22
Q

HHV 4 (ɣ) aka EBV: lytic feature

A
  • Mononucleosis:
    • Fever, chills, sweats, headache, pharyngitis with exudates, lymphadenopathy, splenomegaly, hepatitis, eyelid edema
23
Q

HHV 4 (ɣ) aka EBV: latent feature

A
  • Becomes latent in memory B-cells (1/105 to 1/106)
    • Source of salivary infection (and shedding) and cause of some complications
24
Q

HHV 8 (ɣ) aka KSHV: shedding

A
  • Periodically shed asymptomatically in saliva - explains ease of spread within families
25
Q

HHV 8 (ɣ) aka KSHV: lytic feature

A
  • Kaposi Sarcoma
    • Angioproliferative inflammatory lesion
    • Facilitated by suppressed immune function, also probably by HIV proteins, cytokines, growth factors coded for or induced by HHV-8
26
Q

HHV 8 (ɣ) aka KSHV: latent features

A
  • Latency in B cells
27
Q

HHV 8 (ɣ) aka KSHV: disease in immunocompromised patients

A
  • Kaposi’s sarcoma
  • Primary effusion lymphoma (PEL)
    • B-cell malignancy of serosal surfaces (HIV+)
  • Multicentric Castlemen’s Disease (MCD)
    • Lymphoid tumor (both HIV+ and HIV- people)
28
Q

Mononucleosis: incubation period, virus infection

A
  • 2-4 week incubation period
  • Followed by fever, malaise, adenopathy
  • Mild hepatitis occurs, as well as sore throat
  • Most tissue damage due to cell-mediated response, not the virus
29
Q

EBV vs. CMV mononucleosis

A
  • CMV mononucleosis does not have heterophile antibodies
    • Common diagnostic test for EBV mononucleosis
  • Have similar symptoms
30
Q

Infectious mononucleosis (IM)

A
  • Most often caused by EBV
  • The older a patient is when first infected with EBV, the more likely (>25%) they are to have classic IM syndrome
    • But young children can also develop IM
  • EBV infected B cells in tissues –> you can predict IM signs and symptoms
  • After 4-6 week incubation period during which specific T-cell mediated immunity develops, EBV infected B cells destroyed by cytotoxic T cells
31
Q

Infectious mononucleosis s/s

A
  • Prolonged fever and profound malaise
    • from release of numerous cytokines
  • Exudative pharyngitis
    • EBV is 1 of 4 causes of severe exudative pharyngitis (streptococcus, adenovirus, HSV in adolescents)
  • Lymphadenopathy
  • Splenomegaly
  • Hepatomegaly and/or hepatitis
  • Rash common in patients treated with abx
    • Atypical reaction to drugs, does not imply true allergic reaction
  • Soft palate petechiae, eyelid edema - occasional findings
32
Q

IM without positive Monospot test

A
  • “Monospot-negative” IM
  • May have several causes:
    • Most likely - false-negative test demonstrated by specific serology
    • CMV
    • Other viral infections - rubella, Hepatitis A, HHV 6/7, toxoplasmosis
33
Q

Replicative and latent infection of ɣ-herpesviruses

A
  • EBV from secretions from shedder infects epithelial cells in pharynx of contact
  • Cells are unique in close association with lymphoid tissue (peritonsillar and other tissues in pharynx)
  • At this location, B cells infected –> resulting viremia seeds multiple tissues, especially lymphoid and reticuloendothelial strutures
  • During incubation period EBV-specific T-cell mediated immunity develops
  • Eventually detects and destroys EBV-infected cells, but in doing so causes inflammation and tissue damage (signs and symptoms of EBV infection)
  • Also becomes latent in memory B-cells - sources of salivary infection and shedding, cause of some complications