1 / 30

viral classification

viral classification. Dr SAM. DNA Enveloped. Hepadnavirus Herpesviruses Poxvirus Write a letter to the DNA company and print it on an HHP printer and put it in an envelope. HSV( S&S). gingivostomatitis: vesiclular lesions in mouth, children, asymptomatic, heal 2-3 weeks

cosmo
Télécharger la présentation

viral classification

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. viral classification Dr SAM

  2. DNA Enveloped • Hepadnavirus • Herpesviruses • Poxvirus Write a letter to the DNA company and print it on an HHP printer and put it in an envelope

  3. HSV( S&S) • gingivostomatitis: vesiclular lesions in mouth, children, asymptomatic, heal 2-3 weeks • herpes labialis: vesicles, fever blisters or cold sores • keratoconjunctivitis: corneal ulcers, cause blindness • encephalitis: necrotic lesion in temporal lobe, ↑lymphocyte, ↑ protein, normal glucose (USE PCR to dx) • herpetic whitlow: pustular lesion on finger/hand • disseminated infection • no congenital abnormalities • eye infections

  4. Parvovirus Adenovirus Papovavirus My PAPy does not want to get an envelope from the DNA company DNA Non-enveloped

  5. ADENOVIRUS (S&S) • pharyngitis, acute respiratory distress syndrome • keratoconjunctivitis: swimming pool conjunctivitis (pink eye) • gastroenteritis: with non-bloody diarrhea in children <2 • second most common cause of pediatric gastroenteritis (#1 is rotavirus) • infection affects respiratory tract, GI, and conjunctivas • childhood upper respiratory tract infection: fever, very sore throat, swollen lymph nodes of neck • pus on tonsils and throat

  6. RNA non-enveloped • Picornavirus • Calcivirus • Reovirus PCR

  7. Negative-stranded Viruses • Arenaviruses • Bunyaviruses • Paramyxoviruses • Orthomyxovirus • Filoviruses • Rhabdoviruses Always Bring Polymerase or Fail Replication

  8. Paramyxo-viruses • Possess Fusion F protein cause infected host cell to fuse together in to multinucleated giant cells • BIG PICTURE: • think lungs—LRT infection in kids and URT infection in adults • think kids • think viremia

  9. Segmented Viruses • Bunyaviruses • Orthomyxoviruses • Arenavirus • Reovirus BOAR

  10. POX VIRUSES • REPLICATE IN THE CYTOPLASM • Has a DNA dependent RNA polymerase • BOX shaped • -single, stable serotype

  11. RETRO • 1. Many Cancer causing viruses • 2. HIV • Human Immunodeficiency Virus • AIDS • Acquired Immunodeficiency Syndrome

  12. HIV (Human Immunodeficiency Virus) • AIDS • Acquired Immune Deficiency Syndrome • results in failure of the immune system • Death usually results from an Opportunistic Infection • HIV discovered in 1984 • By who ? • Luc Montagneir - Pasteur Institute

  13. HIV STRUCTURE • Retro Virus • Nucleic acid - RNA (2 strands) • envelope (gp 120 binding sites) • Reverse Transcriptase

  14. HIV Infection (Cellular Level) • 1.ATTACHMENT • HIV gp 120 binding sites must match CD4 receptor sites CD4 Receptor Sites 1. Macrophages 2. Some cells of CNS 3. T4 Helper Cells (CD4 Cells)

  15. HIV Infection • PENETRATION • Viral membrane and host cell membrane merge (fusion) • UNCOATING • Capsid is removed and Viral Genome is exposed

  16. INTEGRATION • Once Viral Genome is integrated - 2 possibilities: • 1. Nothing - Virus is “Latent” • Virus may be latent for days, weeks, months or years • Median latency time = 10 years

  17. 2. HIV Genome can be “expressed” or “Turned On” • Once HIV Genome is “turned on” death usually results within 2 years • What causes the HIV Genome to be “turned on”? • Other infections • Stress or shock to the system • Drug abuse • Alcohol abuse • Nutrition • Exercise (Lack of or too much?) • Sunburn ? • (Herpes Simplex 1)

  18. Once HIV Genome is “turned on” • 5. Biosynthesis • Genome replication • Transcription • Translation • 6. Assembly • Virus particles are put together • 7. Release • Budding

  19. Modes of HIV Transmission • HIV is transmitted by exposure to infected body fluids • 4 Body Fluids • 1. Blood • 2. Semen • 3. Vaginal Secretions • 4. Breast Milk

  20. How are these fluids transferred from one person to another? • 1. High Risk Sexual Contact • unprotected vaginal sex • unprotected oral sex • unprotected anal sex • 2. Needles • Intravenous Drug Abuse (sharing dirty needles) • accidental needle sticks

  21. How are these fluids transferred from one person to another? • 3. Blood to Blood Contact • open sores or wounds • Transfusions • Organ Transplants • Artificial Insemination • 4. Mother to Child • placenta • as baby passes thru the birth canal • breast milk

  22. HIV and the Immune System • 1. Cellular Immune System • cells phagocytize microbes • 2. Humoral Immune System • antibodies to destroy or inactivate microbes

  23. Clinical Stages of an HIV Infection • 1. Acute Infection • Initial infection of HIV (exposure to infected body fluids) • Viremia • Fever • Headaches • Weakness • Muscle and joint aches • May last for a couple of weeks • Normal CD4 cell count 1200mm3

  24. 2. Asymptomatic Disease • CD4 cell count < 1000mm3 • Virus is “latent” inside CD4 cells • Median latency period - 10 yrs. • No signs or symptoms of illness (asymptomatic) • HIV Positive - antibodies can be detected in your blood • Seroconversion • 6 to 8 weeks

  25. 3. Symptomatic Disease • CD4 cell count < 600mm3 • Viral Genome is “turned on”, Symptoms begin to appear • What causes HIV Genome to be turned on? • Other infections • stress • shock to the system • alcohol • drug abuse • nutrition • exercise ?

  26. 3. Symptomatic Disease • Symptoms • chronic fatigue • low-grade fever • night sweats • diarrhea • weight loss • Susceptible to Infections • bacterial pneumonia • meningitis • oral and vaginal yeast infections • tuberculosis

  27. 4. Advanced Disease (AIDS) • CD4 cell count < 200mm3 • Severe Opportunistic Infections • Pneumocysitis carinii pneumonia (PCP) Fungi • Kaposi’s Sarcoma ( Cancer - Skin and Blood vessels) • Toxoplasmosis (Brain) Protozoan • Cryptosporidiosis (G.I. Tract) Protozoan • Other Bacterial, Fungal and Viral Infections

  28. Blood Test - ELISA • Enzyme Linked Immunosorbant Assay • tests for HIV Antibodies • If ELISA is positive, same sample is tested again • If ELISA is positive again, then a Western Blot Test is done. • Western Blot - test for Viral antigens

  29. Treatment for HIV Infection • No Cure • AZT ( Azidothymidine) • Thymine analog • lacks a 3’ OH • Chain Terminator • Inhibits Reverse Transcriptase

  30. Vaccine for HIV ? • HIV mutates too rapidly • Reverse Transcriptase causes at least 1 mutation each time it is used • 1 million variants during Asymptomatic Disease • 100 million variants during Advanced Disease (AIDS)

More Related