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60 Cards in this Set
- Front
- Back
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What Herpes Viruses are in the Alpha group and and what is their site of Latency?
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HHV-1, HHV-2 and HHV-3 (VZV; chicken pox & shingles)
Sensory Ganglia; Neurons |
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What Herpes Viruses are in the Beta Group and what is their site of Latency?
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HHV-5 (CMV), HHV-6 (Human Herpes 6), HHV-7 (Human Herpes 7)
CMV= Lymphocytes & Macs HHV-6 & 7= T-Cells & Monocytes |
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What Herpes Viruses are in the Gamma Group and what is their site of Latency?
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HHV-8 (Karposis), HHV-4 (Epstein Barr)
B-Cells |
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What is the first site of attachement for Herpes viruses?
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Proteoglycans (heparin sulfate)
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Where does the uncoating occur and what happens?
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Occurs at the nuclear membrane and the genome is released into the nucleus
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What remains in the cytoplasm after penetration?
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Some tegument proteins and mRNA remain in the cytoplasm
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What do the immediate (alpha) genes do?
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Encode alpha proteins
DNA-binding proteins that regulate/turn on transcription of viral mRNA's |
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What to the Early (beta) genes do?
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Encode beta genes
Inhibit expression of Alpha genes Initiate viral DNA replication Shut down HOST cell replication/trans/protein syn. Initiate expression of late genes MINOR Structural proteins |
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What do late (gamma) genes do?
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Encode gamma proteins
MAJOR Structural proteins |
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How does Assembly and release occur?
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Genome is replicated in the nucleus
Structural protein are brought in where assemble occurs Virus bud from the Nuc. Mem. BUT loses its Primary envelope Released from cell via exocytosis |
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What is Acyclovir and what is effective agasint and what is not and why?
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Guanosin Analogue used for treatment of the Herpes virus
Effective against HSV and VZV but more active against HSV NOT active against CMV b/c does not encode a TK enzyme |
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What phorphorylates Acyclovir?
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1st phosphorylation is added by a VIRUS enzyme TK (kinase)
2nd and 3rd Phosphorylation is from cellular enzymes |
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How does Acyclovir work?
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After being phosphorylated it competively inhibits dGTP for insertion into the Viral Genome
Which then causes DNA chain termination b/c of lack of 3' OH group |
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What point of activity during infection does Acyclovir work?
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Only has activity against Productive infection NOT latent infection
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How does resistance occur for Acyclovir via TK?
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Loss of gene encoding TK; not much of problem clinically though b/c these viruses are less virulent
Mutation of VK that reduces its affintiy for Acyc. |
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How does resistance occur for Acyclovir another way?
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Mutation of DNA Pol. that reduces its ability to bind ACYC. Triphosphate
They still retain there virulence and often occurs in pts. who are immunocoprimised who are on prolonged treatment |
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What does Ganciclovir do and what is its MOA?
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Guanosine Analogue; Active treament for CMV
MOA is very similar to Acyclovir but can just be phosphorylated by an Enzyme of CMV (UL97) |
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How does resistance occur for Ganciclovir occur?
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Point mutations in gene UL97, which causes the inability to phosphorylate the drug
Mutation in the CMV DNA Pol. which causes less affinty for the Drug |
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What is Cidofovir used for and how?
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Cytidine Analogue, used for treatment of CMV but competes for dCTP incorporation into DNA
BUT also has activity IN VITRO against other viruses |
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How does HSV-1 infect?
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Via contact with contaminated saliva
Remains localized in the oral Enters neurons at site of infection & travels to Trigeminal Ganglion where it establishes latent infection |
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How does HSV-2 infect?
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Sexually transmitted
Remains localized at the genital mucosa Enters neurons at site of infection & travels to Sacral Ganglion where it establishes latent infection |
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How does VZV infect?
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Transmitted via respiratory
Initial replication occurs in the LUNGS Disseminated by Blood & lymph to RES (liver, spleen, nodes) Secondary viremia Laten infection in Sensory Neurons |
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What is Herpes Stromal Keratitis?
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Autoimmune disease of the EYE triggered by HSV
Can progress to blindness Maybe a result of MOLECULAR MIMICRY |
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What is Herpetic Whitlow?
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Infection of the finger
Enters through breaks in the skin Often associated with healthcare workers or a child that sucks their thumb |
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Whatis Eczema Herpeticum?
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Children with Eczema whic makes it easier for HSV to spread to the skin
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What is Encephalitis and what causes it?
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Mainly caused by HSV-1
Symptoms include FLU like symptoms, confussion, seizures & coma |
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Can HSV-2 cause meningitis?
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Yes, but rarely causes encephalitis
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What causes Neonatal herpes?
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Usually HSV-2, but could be HSV-1 if mother has it on her genitals and is then usually contracted during birth; but can occur through nursing
DOES NOT CROSS PLACENTA |
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What is Varicella Pneumonia?
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A complication of VZV, more likely in adults
Can be fatal |
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What is expressed in Latent Herpes and what occurs?
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LATs which encode miRNA
miRNA get spliced from LATs and this then inhibits Apoptosis |
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Why is there no immune response in latent herpes?
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B/C eventhough there are viral transcripts present ther are NO viral proteins
T-Cells can not detect infected cells |
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How does reactivation occur with herpes simplex?
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Occurs following some kind of stress
Viruses travels down neurons to inital site of infection Host response clears viruses more quickly then intial |
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How is the CMV transmitted?
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Contaminated Saliva
Blood Transfusions Sexually Organ Transplants In Utero At birth Nursing |
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Where does the productive infection of CMV occur?
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Fibroblasts, ductal epithelial cells (why you see it in so many fluids), macrophages
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Where does the latent infection of CMV occur?
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Monocyte, stromal cells of the bone marrow
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What is characteristic of CMV Mononucleosis-Like infection?
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Symptoms less severe then EBV-Mononucleosis
HETEROPHILE ANTIBODY NEGATIVE |
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What are characteristics in CMV Congenital Infection?
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Leading cause of congenital infection, in newborns is called Cytomegalic Inclusion; hearing loss and mental retardation are the most common consequences
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How does Cytomegalic Inclusion Disease Occur and what are the common sympotoms?
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Mother is CMV+ and baby is seronegative and then exposed to mothers CMV infection
Can occur In Utero Hearing loss and mental retardation Maternal AB is protective |
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How is the congenital infection of CMV diagnosed?
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By isolating the virus from the infants urine during the first week of life
Damage is done at this point |
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What are the common manifestations of Perinatal CMV and when get it be Dx after birth?
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Pneumonia and hepatitis
Can NOT be picked up in urine until 3-4 weeks after birth |
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What are some important facts about HHV-6 & 7?
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NOT associated much with clinical disease especially 7
Most people have Ab, often asympotomatic Replicates in salivary glands and transmitted via saliva Latently infects T-Cells and Monocytes |
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What is HHV-6 & 7 associated with?
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Exanthema Subitum; Roseola, Sixth disease
Mainly HHV-6 |
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What are the receptors for EBV and where is it expressed?
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CR2 or CD21 are the receptors MHC II are co-receptors
Expressed on B cells or the Oro and Nasopharynx |
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What are the markers for a productive infection of EBV?
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EA, VCA, MA, ZEBRA
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How is ZEBRA associated with EBV?
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Marker for productive infection
Activates Immediate Genes Not expressed in latent |
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What is expressed in the latent form of EBV and where does it occur?
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EBNAs, LP, LMP, and 2 EBER
Only see a couple of viral proteins (EBNA) so immune does not see infection Occurs in Memory B Cells |
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What distinguishes EBV from CMV?
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The production of Heterophile Antibodies
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What will result if EBV activated B cells are not destroye/controlled by T cells?
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A lymphoma or leukemia may result
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Where is the latent virus of EBV and where is reactivation common?
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Latently infected memory B cells and is commonly reactivated in tonsils and oropharynx
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If you have had EBV mono can you get reactivated?
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Yes you can but might be asymptomatic and then just shed the virus and spread it with out knowing
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What is clinical complication of EBV mono?
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Splenic rupture
Pt. needs to stop playing contact sports |
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How do you Dx EBV Mono?
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Downey Cells; large atypical T cells
Heterophile Ab |
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What is strongly associated with Burkitts Lymphoma (EBV)?
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EBNA-1 antigen and EBV DNA are associated with the tumors
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What are the neoplastic cells called in Hodgkin Lymphoma and how many subtypes is EBV assoicated with in HL?
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Reed-Sternberg cells
There are 5 subtypes and EBV is associated with 3 |
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What class of People is associated with Nasopharyngeal carcinoma?
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Asian origin and EBV DNA cells is associated with tumor cells
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What type of infection is Hairy Oral Leukoplakia?
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PRODUCTIVE INFECTION of epithelial cells in the mouth NOT a B Cell transformation or CANCER
Opportunistic in AIDS |
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How is acute infection Dx of EBV done?
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By detection of IgM or VCA or VCA Antibody
NOT EBNA |
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Detection of what would indicate previous infection of EBV?
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VCA and EBNA
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During reactivation of EBV what would you see and not see?
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See EBNA; NOT IgM (only present in Acute)
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What disease is associated with HHV-8 or KSHV and organ is it associated with?
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Kaposi Sarcoma and sequences have been assoiciated with abnormal tissue of the PROSTATE
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