VIRO

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Cards (99)

  • • All DNA viruses are enveloped, except: PAPP smear (Parvo-, Adeno-, Papilloma-, Polyomavirus)
    • All DNA viruses are dsDNA except parvovirus
    • All DNA viruses are linear except PoHPa
    (Polyoma-, Hepadna-, Papillomavirus)
     
    • All DNA viruses have icosadheral capsids except
    poxvirus (complex)
    • All DNA viruses replicate in the nucleus except poxvirus
    (replicate in the cytoplasm – carries own dependent RNA
    polymerase)
  • Parvovirus B19
    A virus in the Parvoviridae family
  • Parvovirus B19
    • ssDNA linear; icosahedral, no envelope (naked); only known human parvovirus (one serotype)
  • Close contact, probably respiratory, transplacental, or from blood and blood products
    Transmission of Parvovirus B19
  • Diseases caused by Parvovirus B19
    • Erythema infectiosum or fifth disease “slapped cheek” rash
    • Transient aplastic crisis
    • Fetal infection (fetal death and “hydrops fetalis”
    • Arthritis
    • Pure red cell aplasia
    • Chronic B19 infection
  • Methods of diagnosis for Parvovirus B19
    • Serology
    • PCR
    • Histology
  • Treatment for Parvovirus B19 is supportive
  • I.V. immunoglobulin can be used with aplastic crisis
  • Prevention of Parvovirus B19 involves avoiding contact with patients with TAC and PRAC patients</b>
  • Adenoviridae
    Family of viruses that have a double-stranded DNA genome and an icosahedral capsid, but no envelope
  • Human Adenovirus
    A type of virus that belongs to the Adenoviridae family and infects humans
  • Human Adenovirus
    • dsDNA linear
    • icosahedral
    • no envelope with approximately 50 human serotypes
  • Site of latency
    Replication in oropharynx
  • Diseases caused by Human Adenovirus
    • URT: Pharyngitis, conjunctivitis, coryza (serotype 3, 7, 8, 19, 37)
    • LRT: bronchitis, atypical pneumonia (serotype 14)
    • GIT: acute gastroenteritis (infantile diarrhea) [serotype: 40, 41]
    • GUT: acute hemorrhagic cystitis (serotype: 7, 11,21)
  • Diagnosis of Human Adenovirus
    • Cell culture (HEp-2) with Cowdry type B intranuclear basophilic inclusion bodies
    • EIA for gastroenteritis (40-41)
    • PCR
  • Treatment of Human Adenovirus
    Supportive
  • Prevention of Human Adenovirus
    Vaccine (adenovirus 4 and 7) for military recruits
  • PAPOVAVIRIDAE: Papillomaviruses and Polyomaviruses
    • The papovaviruses (sigla: pa = papilloma; po = polyoma; va —
    vacuolating agent) are small nonenveloped icosahedral viruses
    which replicate in the nucleus and may transform infected cells.
    1. Papillomavirus: HPV types 1 to 100+ (as determined by genotype; types defined by DNA homology, tissue tropism, and association with oncogenesis)
    2. Polyomavirus: SV40, JC virus, BK virus, KI, WU, Merkel cell
    polyomavirus (MCPyV)
    • Small icosahedral capsid virion
    • Double-stranded circular DNA genome replicated and assembled in
    nucleus
    1. PAPILLOMAVIRUSES
    Virus: Human Papilloma Virus
    Characteristics: dsDNA circular; icosahedral capsid; no envelope (100
    serotypes)
    Transmission: Direct contact, sexual contact for genital warts
    Site of latency: Epithelial tissue (Infect squamous cells and induce
    formation of cytoplasmic vacuole (koilocytes)
    Disease: Skin and Genital warts, benign head and neck tumors, anogenital
    warts
    Diagnosis: Cytology, DNA probes, HPV antigen
    Treatment: Surgical or chemical removal; podophyllin
    Prevention: Vaccination (Gardasil and Cervarix) – 9-16 y.o,
    barrier contraception, avoid contact w/ infected skin
  • HPV
    HPV 6 and 11- Genital warts ( condyloma acuminata), Respiratory Tract papillomas, Most common viral STD

    HPV 16, 18, 31, 33- Carcinoma of the cervix, vulva, penis, anus
    HPV 1,2,4,7- Skin and plantar warts, verruca vulgaris
  • Polyomaviruses
    Virus that infects humans
  • Polyomaviruses
    • dsDNA circular
    • icosahedral
    • no envelope
  • Polyomaviruses are transmitted through direct contact with respiratory secretions
  • Polyomaviruses are ubiquitous in humans
  • Site of latency
    Kidney
  • Diseases caused by Polyomaviruses
    • JCV: Progressive multifocal leukoencephalopathy in patients with AIDS
    • BKV: Hemorrhagic cystitis and nephropathy in patients with solid organ (kidney) and bone marrow transplants
  • Diagnosis of JCV
    PCR (CSF and urine) or EM (brain tissue)
  • Diagnosis of BKV
    PCR or cytology of urine (decoy cells)
  • Treatment of Polyomaviruses is supportive
  • Prevention of Polyomaviruses is to avoid contact with the virus</b>
  • Herpesviruses
    Have large, enveloped, icosahedral capsids containing double-stranded DNA genomes
  • Herpesviruses
    • Encode many proteins that manipulate the host cell and immune response
    • Encode enzymes (DNA polymerase) that promote viral DNA replication and are good targets for antiviral drugs
  • DNA replication and capsid assembly
    Occurs in the nucleus
  • Ways of virus release
    • Exocytosis
    • Cell lysis
    • Through cell-to-cell bridges
  • Types of infections caused by Herpesviruses
    • Lytic
    • Persistent
    • Latent
    • Immortalising (for Epstein-Barr virus)
  • Herpesviruses are ubiquitous
  • Cell-mediated immunity
    Required for control of Herpesviruses
  • Herpes simplex virus
    Herpes simplex virus types 1 and 2 (HSV-1 and -2)
  • Characteristics
    • dsDNA linear; icosahedral with envelope (at least 8 human herpes viruses known)
  • Transmission
    • Direct contact with infected secretions (HSV 1: saliva or direct; HSV 2: sexual or transvaginal)