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51 Cards in this Set
- Front
- Back
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what kind of virus is cytomegalovirus?
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enveloped
dsDNA Herpes family latency, reactivation, life-long infection human CMV (HCMV)=species specific |
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what can CMV cause clinically?
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congenital infection and infection of immunocompromised
may cause heterophile negative infectious mononucleosis (in immunocompetent adults/adolescents) |
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how is CMV transmitted?
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infected secretions
vertical, horizontal (day care), organ transplant, sex, transfusion, breast milk |
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how common is CMV?
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present in 50% NE blood donors
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where can CMV replicate?
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many organs: salivary glands, kidneys
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what do cells infected w/ CMV look like?
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enlarged ("cytomegalic")
may show large intranuclear inclusions |
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how does CMV interact w/ other pathogens? which ones?
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it reduces lethal doses of opportunistic pathogens
p. carinii, Toxoplasmosis, Pseudomonas |
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what are some pathological effects of CMV?
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transient immune suppression w/ reversal helper/suppressor T cell ratios
transient reduction in delayed hypersensitivity |
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what does CMV do in organ transplant pts?
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causes graft rejection
assoc. w/ graft versus host dz in bone marrow transplant |
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why is CMV able to replicate in infected immunosuppressed pts?
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due to property of latency and reactivation
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What does CMV cause in immunoCOMPETENT children and adults?
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1. asymptomatic infection usually
2. "mononucleosis-like" syndrome |
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what is "mononucleosis-like" syndrome?
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caused by CMV
fever, malaise, pharyngitis, atypical lymphocytosis, occasionally involves organs unlike "infectious-mono" (EBV): Not associated w/ positive heterophile test |
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does mononucleosis-like syndrome have a positive or negative result for a heterophile test?
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negative
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How is congenital CMV infection acquired?
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transplacental spread of virus during a PRIMARY infection of mom; less often due to latent reactivation
can occur any trimester primary infection--assoc. w/ most severe consequences |
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what are the clinical Sx of congenital CMV?
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asymptomatic (90%) to severe ("blueberry muffin" baby)
stillbirth, preme, or multi organ and CNS damage--hepatosplenomegaly, jaundice, thrombocytopenia, microceph, cerebral calcif, chorioretinitis, deaf, etc |
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are infants with congenital CMV infection contagious?
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shed virus in saliva for 6 mo, in urine for 50 months
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what's the most common cause of congenital deafness?
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congenital CMV infection
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can CMV infection occur at birth?
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yes, via cervical secretions
usually asymptomatic, assoc. w/ persistence of virus in throat, urine....congenital deafness |
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what does CMV cause in immunocompromised pts?
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severe, maybe fatal from primary or reactivation of latent infection
include: hepatitis, colitis, myocarditis, pneumonitis, lymphadenopathy, fever, mening, retiniitis |
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what's the single most important advance in transplantation
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control of CMV
CMV assoc. w/ rejection, opportunistic infection and CMV dz |
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how is CMV diagnosed in the lab?
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viral isolation
immunostaining rise in Ab titer (primary infection) PCR and other DNA methods |
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How is CMV transmission prevented?
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screening/filter blood products
condoms prophylax w/ antivirals prophylax w/ CMV immune globulin |
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Is there a vaccine for CMV?
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no
Ab only partly neutralizing current studies w/ synthetic polypeptide |
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what antivirals are used for prophylaxis of CMV?
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ganciclovir, valganciclovir
and/or CMV immune globulin |
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How is CMV dz (retinitis, pneumonia in immunocompromised, etc) treated?
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1. gangciclovir (guanosine analog)
2. foscarnet (acts on DNA pol) 3. cidofovir (acts on DNA pol) |
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What are the properties of EBV?
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dsDNA virus
herpes group latency, reactivation, life-long can immortalize cell lines |
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what are the host cells for EBV?
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B lymphs, nasopharyngeal epithelial cells
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how is EBV transmitted?
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"kissing dz"
salivary secretions organ transplant, blood trans |
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how common is EBV?
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over 95% of adults
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what are some clinical syndromes of EBV?
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Infectious mononucleosis
non-specific febrile illness (kids) Burkitt's lymph and nasopharyngeal carcinoma, Hodgkins, T-cell malig, "hairy leukoplakia" of the tongue, B cell lymph in CNS, sm musc tumors lymphoprolif dz w/ congenital immune deficiency or AIDS |
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how bad of a disease is infectious mononucleosis?
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usually self-limited, mild dz of kids and young adults caused by EBV
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what are the systemic symptoms of infectious mononucleosis?
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fever, malaise, anorexia
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what tissues are involved w/ infectious mono?
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prolif of lymphoid tissue:
lymphadenopathy (post. cervical) splenomegaly (Beware splenic rupture during PE!) oropharyngeal liver, skin (rash), thrombocytopenia, NS (guillan-barre), heart, lungs, etc. |
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how does one get infectious mono?
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close contact (kissing)
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whats the course of infectious mono?
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incubation 6-8 wks
major acute phase: few weeks then gradual convalescence fever for several wks, lassitude for months |
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are secondary infections common with infectious mono?
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rare.
chronic or relapsing "mono" often associated w/ immune deficiency |
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what are the major lab findings of EBV?
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rise in # or proportion of lymphs in blood
atypical lyphs (downey cells) heterophile Ab's anti-EBV Ab's PCR of CSF/periph blood for viral presence and titer |
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what are Downey cells
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activated T lymphs reacting against EBV infected cells
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what are heterophile Ab's?
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Ab's in response to EBV infection (other Dz's too) that react w/ Ag's other than EBV Ag's.
present in 90% pts w/ IM |
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how are EBV-assoc heterophile Ab's distinguished from those due to Serum sickness or in some healthy ppl?
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perform differential agglutination test
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how is a differential agglutination test performed?
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pt serum mixed (pre-absorbed) with GPK cells or bovine RBC's
then add horse RBCs agglutination of the horse RBCs are indicated by + or 0 |
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how would a differential agglutination test read for infectious mono?
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+hRBC=++++
pre-abs w/ GPK, then hRBC=+++ pre-abs w/bRBC, then hRBC=0 bRBC=bovine RBC GPK=guinea pig kidney cell hRBC=horse RBC |
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what is considered a positive result for an agglutination test for mono?
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high titer of "heterophile" Ab's
Ab's agglutinate sheep or horse RBCs and can be absorbed by beef RBCs BUT NOT by GPK cells |
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what would a heterophile negative test indicate?
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can rarely be "mono", but more commonly atypical forms
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what does antibody (IgG) to viral capsid Ag (VCA) of EBV indicate?
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past infection
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what does IgM to VCA indicate?
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recent infection of EBV
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what are some antigens associated with EBV?
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viral capsid antigen (VCA)
early antigen (EA) nuclear antigens (EBNA) fxn not all known, some maybe for immortalization |
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whats the tx for EBV?
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supportive
??steroids for severe dz no truly effective antivirals, sometimes acyclovir used |
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how is EBV prevented
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avoid close personal contact
no vaccine |
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what's the role of EBV in tumors?
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uncontrolled proliferation in immunosuppressed (HIV, organ trans, congenital) causes lymphomas:
CNS, B cell, intestinal |
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what is the association of EBV w/ Burkitt's lymphoma?
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association w/ African but NOt U.S. populations
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