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67 Cards in this Set
- Front
- Back
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Give a general description of the herpesviruses and poxviruses
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Large and complex
Many virus-specific enzymes (and drug targets) Less dependent on functions supplied by host Can infect several tissues and cell types |
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Give a brief, generalized description of the Hep. B virus
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Very small
Targets liver hepatocytes |
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Describe the "general principles" of the herpesviruses
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Large dsDNA genome
Enveloped virion Transmission by close contact Replicates in host cell nucleus No integration Can have latency |
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How many human herpesviruses are there
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Eight
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Which herpesviruses fall into the alpha subclass
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Herpes simplex virus 1 & 2
Varicella zoster virus |
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Which herpesviruses fall into the beta subclass
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Human cytomegalovirus
Human herpesvirus 6 Human herpesvirus 7 |
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Which herpesviruses fall into the gamma subclass
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Epstein-Barr virus
Human herpesvirus 8 (aka Kaposi's sarcoma HV) |
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Which herpesviruses are/can be sexually transmitted
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HSV-1
HSV-2 HCMV KSHV |
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Which herpesviruses cause cancer
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Gamma subgroup
(EBV & KSHV) |
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Describe the characteristics of the herpesvirus subclass alpha
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Replication- fast
Cellular effects- Shutdown Outcome- Cytolytic Site of latency- Nerve ganglia |
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Describe the characteristics of the herpesvirus subclass beta
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Replication- slow
Cellular effects- no effect Outcome- lytic/cytomegalic Site of latency- lymph + glands |
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Describe the characteristics of the herpesvirus subclass gamma
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Replication- slow
Cellular effects- activate Outcome- proliferative (cancer) Site of latency- B cells + monocytes |
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What structure on a herpesvirus allows it to attach to a cell
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glycoprotein spikes
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Describe the genome of a herpesvirus
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dsDNA
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Describe the general points of herpesvirus replication
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Replication of viral DNA is in the nucleus
Translation in cytoplasm Assembly in nuceleus Productive infection is lytic |
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What is the clinical definition of primary infection of an alpha-herpesvirus
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First exposure to HSV
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What is the clinical definition of initial infection of an alpha-herpesvirus
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Exposure to HST-1/2 after primary infection with the other type
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What is the clinical definition of recurrent infection of an alpha-herpesvirus
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virus shedding after reactivation from latency
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What cells do HSV-1/2 infect
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Epithelial cells
Fibroblasts Sensory neurons |
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What is the fundamental process of pathogenesis for HSV
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Infection of mucosa then sensory ganglia then latency (followed by reactivation at some point in mucosa
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Where is HSV released during a productive (not latent) infection
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Into saliva or genital secretions or shed from cutaneous lesions
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Describe the latency of HSV
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In sensory nerves
episome, not integrated No virion production |
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Describe reactivation of HSV
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Stimuli (neuronal or immune perturbation)
Replicates in neuron, returns to mucosa or skin Immune response clears mucosal or cutaneous infection |
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When are systemic infections of HSV common
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In the immunocompromised
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Describe keratoconjunctivitis
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Caused by HSV-1 (also adenovirus)
Most common infectious cause of corneal blindness Dendritic lesions, ulcers, pain, photophobia Healing can take 1 mo Recurrence common, immunopathologic reaction |
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Describe encephalitis caused by HSV-1
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Most common viral encephalitis
Fever, headache, seizure, altered consciouness, disordered mentation Often lethal if untreated Can be caused by primary or reactivation infection |
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What type of HSV-2 infection is most likely to be spread to a newborn during the birthing process
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Primary
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What are also included in a differential diagnosis that includes HSV-1
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Varicella-Zoster virus
Impetigo Hand, foot, and mouth disease Corneal abrasion, erosion or ulcer Fungal or bacterial infection of eye Other viral encephalitides |
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What are also included in a differential diagnosis that includes HSV-2
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Candida infection
Syphilis chancre |
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Describe the general characteristics of varicella-zoster virus (VZV)
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Smaller than HSV
Replicates similarly to HSV Latency in sensory neurons Two distinct infection types |
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What is the primary infection of VZV also known as
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Varicella (Chicken Pox)
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What is the recurrence infection of VZV also known as
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Herpes Zoster (Shingles)
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How does a primary VZV infection present
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Papulovesicular rash beginning on head or trunk and spreading to limbs
(Prodrome of fever, anorexia, headache, and malaise) |
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During the contagious period of a VZV infection, where are the viruses released
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Into respiratory secretions (major source of new infections
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When VZV recurs (as shingles), where does it appear
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Along a single dermatome
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A differential diagnosis including VZV would also include
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Generalized herpes zoster or simplex
Dermatitis herpetiformis Impetigo Guttate psoriasis Contact dermatitis |
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Which is the only herpes virus that has a vaccine
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VZV
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What does thymidine kinase do in the herpesviruses
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?Incorporates thymine (or acyclovir hopefully) into replicating DNA?
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Describe the general characteristics of CMV
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Large genome
No thymidine kinase (acyclovir won't work well) Most people worldwide are infected Similar to HSV, but replicates slowly and makes cells greatly enlarged |
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Where is CMV in its latent stage
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Monocytes and dendritic cells (can also be in solid tissue)
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What are triggers for reactivation of CMV
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Sensitive to cell differentiation factors
Mechanisms for control of host cell metabolism, immunity contribute |
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An in utero infection of CMV could cause what
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Birth defects
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What stage of pregnancy with in utero infection of CMV results in the worst symptoms
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First trimester (microencephaly)
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What are some possibilities with congenital CMV infection
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Chorioretinitis and/or hearling loss
Serious mental retardation Microencephaly, intracranial calcifications Generalized cytomegalic inclusion disease |
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What are the clinical manifestations of a CMV infection in an adult
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Mononucleosis syndrome
Disseminated infection in immunocompromised Pneumonia, hepatitis, retinitis |
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What are some laboratory diagnostic features of a CMV infection in adults
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viral load in WBCs, urine has best prognostic value
Giant cells with inclusion bodies in lung, urine |
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What is a notable characteristic of an HHV-6,7 infection in an infant
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Prolonged high fever followed by rash (roseola)
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Where does HHV-6 replicate
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many cell types, skin especially
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Where does HHV-7 replicate
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highly specific for CD4+ T cells
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When does HHV-6 reactivate
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Only in immunosuppressed
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Febrile seizures in infants without rash might be caused by
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HHV-6 or HHV-7
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A differential diagnosis including HHV-6/7 might also include
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Erythema infectiosum (Fifth disease)
Febrile seizure (unrelated) Measles, rubella Pneumonia |
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Clinical manifestations in adults with HHV-6/7 primary infection might be
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Prolonged lymphadenopathy
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What is the major disease known to be associated with primary KSV infection
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Trick question, there is none known
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Disease is associated with what stages of a KSV infection
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latent or prolonged infection
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Differential diagnosis with KSHV would include
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Hemangiomas
Venous lakes Purpura Nevi and melanomas |
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What disease(s) is(are) associated with latent HHV-8 (KSHV) infection
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Body cavity-based lymphoma (a defining illness for AIDS, clonal neoplasia)
Castleman's disease (polyclonal neoplasia) |
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Describe some properties of EBV
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Two types
Humans are only reservoir Primary infection causes most infectious mononucleosis Associated with cancer (Burketts lymphoma?) |
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Describe the notables replication cycle of EBV
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Cellular transcription factors determine virus fate
Transactivates many cellular genes |
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Describe the pathogenesis of EBV during latent infection
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Antigen-naive tonsilar B cells are principal target
Infected B cells proliferate after primary infection Causes non-specific Ig synthesis Infected cells induce marked T cell activation Hepatomegally etc |
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What are the clinical manifestations of infectious mononucleosis (EBV) (kissing disease) and what causes the symptoms
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Fever, sore throat, fatigue, enlarged lymph nodes and spleen, others
Symptoms due to cytokine secretion and energetics of lymphocyte expansion |
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What are the diseases associated with EBV
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Infectious mononucleosis
Oral hairy leukoplakia Burkitt's lymphoma Nasopharyngeal carcinoma Post-transplant lymphoproliferative disease Non-hodgkin's lymphoma EBV-associated Hodgkin's lymphoma |
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Characteristics of Oral hairy leukoplakia
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Observed in AIDS
Wart-like lesions in epithelium of lateral tongue borders EBV induced dysregulation of epithelial differentiation |
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Characteristics of Burkitt's lymphoma
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Rapidly growing monoclonal tumor, initially starting near jaw, spreads to other tissues
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How do poxviruses differ from herpesviruses
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Cytoplasmic replication
Provide all enzymes neeeded Do not establish latency |
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Smallpox is caused by what organism
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variola
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Molluscum contagiosum causes what
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benign wart-like tumors
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