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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

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viral classification

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  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)

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