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57 Cards in this Set
- Front
- Back
What is the one less common herpes virus that affects <5% of general population?
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KSHV
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Structural characteristics of herpes viruses
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LARGE dsDNA genomes within enveloped icosohedral capsid
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What is the MOST important characteristic of herpes viruses
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Ability to establish latency
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3 subfamilies of herpes
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alpha, beta, gamma
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Characteristics of alpha herpes viruses
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Neurotropic; Broad host range; Rapid reproductive cycle, latent infection of sensory ganglia
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Characteristics of beta herpes viruses
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Restricted host range (only humans); Slow reproductive cycle, cytomegalic, latent infection of secretory glands, lymphoreticular cells, kidneys, lymphoid tissue
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Characteristics of gamma herpes viruses
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Restricted host range, lyphotrophic, latent infection of B-lymphocytes, oncogenic
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What are the alpha herpes viruses?
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HSV1, HSV2, VZV
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During latency, how is the EBV genome maintained?
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Genome maintained as a large circular plasmid (episome) by host replication machinery (EBV)
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What are the beta herpes viruses?
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Cytomegalovirus (CMV); Human herpes virus 6 and 7 (HHV6 and HHV7)
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What are the gamma herpes viruses?
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Epstein-Barr virus (EBV), Kaposi's sarcoma-associated herpes virus (KSHV, aka HHV8)
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To what cells is CMV trophic?
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Myeloid lineage
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To what cells is HHV6 and HHV7 trophic?
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T cells
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Primary infections of CMV may result in ___________
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cold like symptoms, or mononucleosis (only 15% of mononucleosis)
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What kind of reactivations occur in CMV?When?
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Probably a few times a year but there aren't any symptoms
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How to detect a prior/current CMV infection?
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anti-CMV IgG
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Seroprevalence of CMV in US
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50% but approaches 100% in elderly
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How is CMV transmitted?
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Shed in saliva, breast milk, urine, cervical secretions, semen
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How does CMV affect developing fetus?
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Only human herpesvirus that is efficiently transmitted transplacentally to developing fetus.
If seronegative mother gets infected, there can be serious birth defects. |
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What special risks of CMV do transplant patients experience?
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Since they're transiently immune compromised, the latent, endogenous CMV can be reactivated. Or Can acquire CMB from donor organ/tissue.
Can develop CMV pneumonitis or CMV infection of transplanted organ. Associated with organ rejection. |
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What are transplant patients treated with to prevent CMV complications?
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Prophylactially: ganciclovir or CMV Ig
Or preemptively monitored for evidence of CMV virema, antigenemia, or DNAemia and treated with antivirals at first sign of active viral infection. |
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What special risks of CMV do AIDS patients experience?
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Most AIDS patients are CMV seropositive and will reactivate latent CMV as their immune system fails
CMV correlates with CD4+ T cell count < 50-100 cells/cc predictive of CMV Retinitis progressing to blindness Oral and GI tract ulceration Dementia Multi-organ system infection |
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How are AIDS-related reactivations/infections with CMV treated?
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Usually resolves with effective antiretroviral treatment (immune reconstitution). Antivirals can be given.
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_ is the major infectious cause of birth defects
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CMV
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7 diseases caused by CMV
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1) Cytomegalovirus-inclusion disease of newborn (transmitted in utero)
2) GI tract ulcerations 3) mononucleosis 4) Hepatitis (immunosuppressed) 5) Pneumonitis (immunosuppressed) 6) Retinitis (AIDS) 7) Multi-organ system infection (immunosuppressed) |
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Closely related ubiquitious herpes viruses infecting T cells
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HHV6 and HHV7
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Causative agent of roseola, relatively benign syndrome characterized by higher fever and severe rash
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HHV6
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elatively benign syndrome characterized by higher fever and severe rash in infants, caused by HHV6
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Roseola infantum
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Which herpesvirus subfamily is associated with oncogenesis?
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Gamma (EBV, KSHV)
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Which cells do EPV and KSHV infect?
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B cells.
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Immortal B cells lines infected with _____ can be cultured from the blood
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EBV
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Primary EBV infection results in _______
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mononucleosis
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Mononucleosis can be caused by ___ and ____
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EBV(70%) and CMV (15%)
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Clinical signs and sx of mononucleosis
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fever, sore throat, swollen tonsils and cervical lymph nodes, enlarged spleen, mild hepatitis.
Peripheral blood smear reveals atypical lymphocytes |
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Dx of EBV-induced mononucleosis
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“atypical” mononuclear lymphocytes
Heterophile antibody positive IgM cross-reactive to Paul Bunnell antigen on SRBCs (Monospot assay) |
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What is heterophile antibody?
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IgM that recognizes the Paul-Bunnell antigen on sheep and bovine erythrocytes, serving as a marker for EBV mononucleosis and can generally be detected by end of first week of illness
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T/F Presence of IgG reactive with EBV antigens is indicative of current EBV infection
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F, only a prior infection. Use heterophile antibody with confirmatory IgM reactivity test
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How is EBV genome maintained in infected cells?
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As circular episome in the nucleus. NOT integrated into host DNA.
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T/F During latent period no infectious virus is produced.
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T
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Replication of the episome requires what?
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1) One viral protein : EBV nuclear antigen 1 (EBNA-1)
2) Host replication factors |
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T/F latently infected B cells with EBV are immortal
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T
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What malignancies are associated with EBV? (non immunocompromised)
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1) African Burkitt's lymphoma
2) Asian nasopharyngeal carcinoma 3) Hodgkins lymphoma |
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What malignancies or neoplasias are associated with EBV? (immunocompromised)
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Lymphoproliferative disorders/lymphomas
uncontrolled growth of EBV+ B cells Oral hairy leukoplakia white “hairy” patches on the lateral tongue |
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Oral hairy leukoplakia is associated with what infection?
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EBV
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What virus is commonly associated with B cell lymphoproliferative disorders in AIDS patients?
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EBV
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How is Kaposi's sarcoma different from the other herpes viruses?
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Its prevalence in the population is very low (2%)
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KSHV: Where does it replicate initially? Where does it latently infect?
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replicates initially in the oral epithelium
latently infects & immortalizes B cells |
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Who gets KS primarily?
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AIDS & transplant patients, older men from Mediterranean regions
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What isthe primarily disease caused by KSHV?
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Primary effusion lymphoma
B cell lymphomas in AIDS patients latent KSHV |
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Multicentric Castelman’s disease : associated with what?
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benign growth of lymphoid tissues, expanded germinal centers
may be associated with lytic KSHV replication |
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KSHV aka
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HHV8
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T/F Multinucleated giant cells and intranuclear inclusion are common in herpes viruses
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T
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How does CMV infection differ in
A) AIDS patients B) Patients who've had bone marrow transplant |
A) CMV retinitis and colitis
B) CMV pneumonitis (severe pneumonia) |
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T/F CMV antigen is only present when virus is actively replicating in blood
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T
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What is the nucleic acid like in ALL herpes viruses?
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ds linear DNA
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T/F All herpes viruses are enveloped
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T
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Monospot test is used for
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Detecting heterophile antibody, antibody against EBV that cross reacts with and agglutinates sheep RBCs.
Rapid screening test for mono. |