Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
40 Cards in this Set
- Front
- Back
Herpes virus morphology/classification
What are its layers? |
enveloped, double stranded DNA virus
Envelope - glycoproteins Tegument - polymerase Nucleocapsid |
|
What are the 3 major subfamilies of herpes virus that infects humans?
Where do they establish latency? |
1. alpha (HSV1,2, VZV, herpes type B)
-latency in neurons 2. Beta (CMV, HHV6, 7) -Latency in monocytes and lymphocytes 3. Gamma (EBV, HHV8) -latency in B cells |
|
How is EBV transmitted?
|
saliva
|
|
What are the EBV receptors and where are they located?
Co-receptor? |
CD21 or CR2 (C3d complement receptor) on B cells and oral epithelial cells
Co-receptor is MHC class II molecules on B cells |
|
In EBV viremia, approx. what percentage of B cells are infected?
|
20% of B cells
|
|
What happens in EBV infection
a. initially b. mid to late |
a. Lytic infection of B cells, viremia
b. EBV establishes latency --> replicates as an episome Immortalizes B cells --> polyclonal activation of B cells --> secretion of non-EBV antibodies, activates Cyt T cells --> kills B cells --> symptoms |
|
Why are antiviral drugs ineffective against EBV infection?
|
Antivirals are only effective against actively replicating virus
Symptoms of EBV occur after lytic cycle has been completed, and T cell response to latent infection kills B cells |
|
What are 2 early antigens of EBV?
When are they expressed, and why is this important? |
polymerase and thymidine kinase
Expressed in lytic infection, site of antiviral activity |
|
What are the viral capsid antigens (VCAs) of EBV?
When are they expressed and what are they required or? Test for these? |
late structural genes
Expressed in lytic infection, used for production of mature virions Serology ordered - IgG and IgM antibodies to these antigens |
|
What are the EBNA (nuclear antigens) required for?
When are they expressed? |
antigens required for maintenance of latent infection
Expressed after resolution of acute infection |
|
What are the latent membrane proteins (LMPs)?
Test for these? |
membrane proteins of EBV that have a role in malignancy
LMP1 - stimulates B cells through CD40 LMP2 - bridges B-cell receptor with Ig --> stimulates proliferation No serological test |
|
What is the monospot test?
For whom is the test diagnostic? |
Diagnosis of EBV mononucleosis
Looks for heterophile antibodies produced by EBV-infected B cells (doesn't actually find EBV) by presenting antigens on RBCs --> look for agglutination Diagnostic for EBV in people over 5 years old |
|
What is the serologic time course of...
a. IgG-VCA b. IgM-VCA (<4yrs) c. IgM-VCA (>4yrs) d. Early antigen e. Nuclear antigen |
a. peaks at 2 weeks, persists for years
b. peaks at 2 weeks, out by 4 weeks c. peaks at 2 weeks (higher), out by 3 months d. Peaks in 2 months e. Low level, increases over months-years, lifelong |
|
What is the time course for VCA IgG in acute infection
a. before b. acute c. convalescence |
a. none
b. + c. + |
|
What is the time course for VCA IgM in acute infection
a. before b. acute c. convalescence |
a. none
b. + c. none |
|
What is the time course for Early Antigen in acute infection
a. before b. acute c. convalescence |
a. none
b. + c. some |
|
What is the time course for EBNA in acute infection
a. before b. acute c. convalescence |
a. none
b. none c. + |
|
What is the peak infectious mononucleosis age?
|
20
|
|
How long can shedding of EBV last after acute infection?
|
months
shedding rate 50-100% |
|
What is the incubation time for EBV mono?
|
15-45 days
|
|
What are symptoms of EBV mono?
|
1. Acute sore throat with exudative tonsillitis
2. Fever 3. malaise 4. myalgia 5. headache 6. lympadenopathy 7. hepatosplenomegaly |
|
What are 7 types of lymphoma that are complications of EBV lymphoproliferative syndrome?
|
1. Endemic Burkitt's lymphoma
-malignant tumor of jaw and viscera -endemic to malaria-prevalent regions 2. Non-endemic Burkitt's lymphoma -only 20% EBV positive, less strong of a link 3. Nasopharyngeal carcinoma (China) 4. Hodgkin's - 50% 5. non-Hodgkins in HIV 6. CNS lymphoma in AIDS 7. Post-transplant lymphoproliferative disorders -hairy leukoplakia in profound immunosuppression |
|
What are 5 differential diagnoses of EBV mono?
|
1. falso monospot test (in kids < 5yo)
2. CMV mono 3. Acute retroviral syndrome 4. Adenoviral pharyngitis 5. Streptococcal pharyngitis |
|
How is CMV transmitted?
|
Saliva
Respiratory droplets (large) Semen Blood Transplacental Post-op |
|
What types of infections does CMV cause and to which types of cells
|
1. Productive, lytic, acute infection
-fibroblasts, epithelial cells, macrophages, lymphocytes 2. Latent infection (for life) -T cells, macrophages |
|
What are 4 ways in which the pathogenesis of CMV is different from EBV?
Similar? |
1. CMV does not immortalize cells
2. Symptoms less severe than EBV 3. Monospot negative 4. EBV IgM negative, CMV IgM pos. |
|
What is signficant about the histology of CMV
|
'owl eye' inclusions
|
|
Clinically, how does CMV infection look?
|
Most commonly asymptomatic
Infectious mononucleosis type syndrome -20% of cases -similar to EBV clinical, but less specific |
|
What happens in CMV-causing congeital infection?
What are the sequelae? |
Transmission of CMV in utero to fetus (among the TORCH organisms) --> congenital abnormalities
-small, microcephalic, deaf, mental retarded, jaundice, thrombocytopenia..death |
|
What are 4 CMV therapeutics?
|
Ganciclovir - chain terminator but poor bioavail.
Valganciclovir Foscarnet Cidofovir - chain terminator |
|
What 5 syndromes can CMV cause?
|
1. GI - colitis, esphagitis, pan-enteritis
2. Eye-chorioetinitis 3. Lungs - pneumonitis 4. Nervous - encephalitis, menengitis, myelitis 5. Graft failure in transplant patients |
|
Mumps -
a. virus? b. nucleic acid? c. morphology |
a. paramyxovirus
b. neg. ss RNA, unsegmented c. helicial nucleocapsid, enveloped hemagglutinin-neuraminidase, fusion protein |
|
Mumps virus
a. transmission b. replication c. type of infection d. spreads to where? |
a. respiratory, saliva
b. epithelial cells of nasopharynx c. lytic infection. d. Parotid gland |
|
Symptoms of mumps
|
Headache, malaise, low fever
parotitis (30-40%) |
|
What are complications of mumps? (3)
|
CNS - meningitis, encephalitis, deafness
orchitis --> sterility pancreatitis |
|
How do you diagnose mumps?
|
clinical - parotitis and fever
viral culture --> syncitia PCR --> detect virus Serologic --> IgM (acute), IgG |
|
How do you prevent mumps?
|
vaccine
|
|
What shows up on a CBC in EBV mononucleosis?
|
1. Increase in lymphocytes (>50%)
2. Increase in atypical lymphocytes (>10%) 3. Development of heterophile antibodies - IgM, positive after 1 week 4. Development of anti-EBV antibodies |
|
What are some acute complications of EBV mono?
|
1. Upper airway obstruction
2. Splenic rupture (esp. wit minor trauma) --> internal bleeding 3. CNS involvement - encephalitis, meningitis, myelitis 4. EKG abnormalities, myocarditis 5. Hemolytic anemia 6. Granulocytopenia 7. X-linked lymphoproliferative syndrome |
|
What happens in duncan's syndrome (x-linked lymphoproliferative disorder)?
|
Defect in SLAM (T cell gene signaling lymphocyte activation)
In 1/3 - excessive T cell suppression leads to hypogammaglobulinemia In 2/3 - Burkitt's lymphoma |