1 / 65

DNA Viruses

DNA Viruses. Samuel Aguazim MD Lange Chapters 37 & 38. Two types of DNA Viruses. 1. Naked: Parvovirus, Papovaviruses , Adenovirus 2. Enveloped : Hepadnaviruses , Herpesviruses , Poxviruses. Replication.

chipo
Télécharger la présentation

DNA Viruses

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. DNA Viruses Samuel Aguazim MD Lange Chapters 37 & 38

  2. Two types of DNA Viruses 1. Naked: Parvovirus, Papovaviruses, Adenovirus 2. Enveloped: Hepadnaviruses, Herpesviruses, Poxviruses

  3. Replication All DNA Viruses except hepatitis B duplicate their DNA by using it as a template to make more DNA Hepatitis B’s DNA polymerase has reverse transcriptase activity.

  4. Parvoviruses • Parvovirus B19 is a naked, single stranded DNA virus that replicates in erythrocyte precursors. • Reservior: respiratory droplet • Transmission: resp droplet, formites, vertical transmission. Diseases • Fifth disease (erythema infectiosum, slapped cheek fever) • Chronicanemia in immunocompromised • Aplastic crises in sickle cell patients • Hydrops fetalis • Rash & arthralgias( adult predominantly)

  5. Papovaviruses (Papilloma virus) • Human Papillomavirus • Diseases: • Cervical and Penile Carcinoma:HPV 16 and 18: Early proteins E6 and E7 inactivate tumor supressor functions of p53 and p110-Rb respectively. • Cutaneous warts(skin) HPV 2 & 4 • Plantar warts:HPV 1 • Anogenital Warts (condylomata acuminata)- may regrow after removal but are benign.( HPV 6&11)

  6. Vaccine for HPV Gardacil covers HPV 6,11,16 & 18 DIAGNOSIS:Cutaneous- clinical ground Genital: finding of Koilocytic cells( cells with perinuclearcytoplasmic vacuolization & nuclear enlargement) in pap smears. Treatment: Imiquimod ( induced pro- inflammatory cytokines)

  7. Koilocytes

  8. Papovaviruses(Polyomaviruses) Diseases: • BK: • Reservior & transmission: respiratory • Pathogenesis: latent infection in kidney • Causes kidney disease and is often associated with kidney transplantation. • Diagnosis: ELISA, PCR • TREATMENT: SUPPORTIVE • VIRUS:JC • RESERVIOR AND TRANSMISSION: RESPIRATORY • PATHOGENESIS: Infect in oligodendrocytes= demyelination • Is associated with progressive multifocal leukoencephalopathy, a slow disease of immunocompromised patients • Diagnosis: ELISA, PCR • TREATMENT : SUPPORTIVE

  9. Adenoviruses • Naked, icosahedralds viruses with fibers projecting from the capsid’spenton subunits. Diseases: • Pharyngoconjunctivitis and keratoconjunctivitis: “pink eye” – conjuntivae are inflamed with a watery exudate • Acute respiratory diseases: military/vaccine serotypes 3, 4,7 & 21 • Adenovirus 40 and 41:gastroenteritis • Acute hemorrhagic cystitis( boys 5-15) 11,15 • Gastro enteritis ( infantile): day care( 40-41)

  10. Adenovirus Fibers

  11. Hepadnavirus We will have a separate lecture for the Hepatitis Viruses

  12. Herpesviruses

  13. Herpesviruses • Herpes simplex viruses I & II • Varicella-Zoster Virus • (This 3 above cause vesicular rash) • Cytomegalovirus • Epstein Barr Virus (EBV) • Human Herpes Viruses 6 &8 • Characteristics • Large, linear Ds DNA • Enveloped(derived envelop from nuclear membrane), icosahedral • Intranuclear inclusion bodies • Establishes latency

  14. Herpes Simplex Viruses I & II • Cause either acute or latent infections • Latent infections cannot be treated by acylovir: • reason: virus does not make thymidine kinase which is required to activate acyclovir by phosphorylation of acyclovir.

  15. HSV-1 & HSV II

  16. Herpes simplex virus can set up a primary infection in the lips, move to the trigeminal  ganglion where it can remain latent.

  17. Tzank smear

  18. Gingivostomatitis looks different from a cold sore

  19. Herpetic whitlow on the finger and on the wrist

  20. Genital herpes on penis area

  21. NEONATAL HERPES

  22. Varicella Zoster Virus • Primary Infection: Varicella or Chicken pox • Lesions start as papular and then progress to vesicular and then pustular. • Asynchronous rash • Latent in neurons • Contagious for 6 days after all lesions have dried • Live attenuated vaccine reduces the incidence of chicken pox. • Varicella Pneumonia and encephalitis(rare) • Reye syndrome (Aspirin)

  23. Varicella Zoster Virus (VZV) 2. Secondary Infection: • Herpes Zoster or Shingles • Clusters of vesicular lesions, usually along a single sensory dermatome, accompanied by nerve pain • Tx: Varicella zoster immunoglobulin (VZIG) & Acyclovir • Both chicken pox and VZV are much more severe in immunocompromised patients • Prevention: live, attenuated vaccine

  24. Herpes Zoster following the dermatomal pattern

  25. Cytomegalovirus (CMV) • crosses the placenta, acquired during birth, mother’s milk, direct contact, sexual contact, blood transfusions or organ transplant. • When CMV replicates, it produces cells with typical large, purple intranuclear inclusion bodies surrounded by a halo (owl’s eyes)

  26. OWL’S EYE INCLUSION

  27. Cytomegalovirus (CMV) Diseases Many are asymptomatic Heterophile negative mononucleosis (immunocompetent) Retinitis and interstitial pneumonitis in immunocompromised patients Neonates: cytomegalic inclusion disease –microcephaly,seizures,deafness, hepatosplenomegaly with thrombocytopenic purpura, pneumonitis, CNS calcifications.

  28. Dx: special tubes called shell vials PCR, The inclusion bodies are intranuclear and have an oval owl's-eye shape 4 fold or greater rise in ab titer Cmv antigenemia( pp65) Rx: in healthy, supportive IM ( AIDS or transplant pts) Ganciclovir and foscarnet, valganciclovir(oral), cidofovir and fomivirsen

  29. Epstein Barr Virus • Infects oral epithelial cells and B-lymphocytes Diseases • Mononucleosis: - 15-25 year old: called the “kissing disease” - severe fatigue - pharyngitis/tonsillitis similar to strep throat. - postcervical lymphadenopathy - hepatomegaly and spenomegaly • Burkitt’s lymphoma -Oncogenic potential in Africa • Nasopharyngeal carcinoma – men from Southern China • Hairy Cell leukoplakia of the tongue • X-Linked Lymphoproliferative syndrome(severe, fatal)

More Related