lecture 10..............................pdf
- 2. WHAT IS HIV?? “Human Immunodeficiency Virus” A unique type of virus (a retrovirus) Invades the helper T cells (CD4 cells) in the body of the host (defense mechanism of a person) Threatening a global epidemic. Preventable, manageable but not curable.
- 3. OTHER NAMES FOR HIV Former names of the virus include: Human T cell lymphotrophic virus (HTLV-III) Lymphadenopathy-associated virus (LAV) AIDS-associated retrovirus (ARV)
- 4. WHAT IS AIDS ??? “Acquired Immunodeficiency Syndrome” HIV is the virus that causes AIDS Disease limits the body’s ability to fight infection due to markedly reduced helper T cells. Patients have a very weak immune system (defense mechanism) Patients predisposed to multiple opportunistic infections leading to death.
- 5. AIDS (definition) Opportunistic infections and malignancies that rarely occur in the absence of severe immunodeficiency (eg, Pneumocystis pneumonia, central nervous system lymphoma). Persons with positive HIV serology who have ever had a CD4 lymphocyte count below 200 cells/mcL or a CD4 lymphocyte percentage below 14% are considered to have AIDS.
- 6. HIV •Human Immunodeficiency Virus •H = Infects only Human beings •I = Immunodeficiency virus weakens the immune system and increases the risk of infection •V = Virus that attacks the body
- 7. AIDS •Acquired Immune Deficiency Syndrome •A = Acquired, not inherited •I = Weakens the Immune system •D = Creates a Deficiency of CD4+ cells in the immune system •S = Syndrome, or a group of illnesses taking place at the same time
- 8. HIV and AIDS • When the immune system becomes weakened by HIV, the illness progresses to AIDS • Some blood tests, symptoms or certain infections indicate progression of HIV to AIDS
- 9. HIV-1 and HIV-2 • • HIV-1 and HIV-2 are • Transmitted through the same routes • Associated with similar opportunistic infections ▪ • HIV-1 is more common worldwide ▪ • HIV-2 is found in West Africa, Mozambique, and Angola
- 10. HIV-1 and HIV-2 • HIV-2 is less easily transmitted • HIV-2 is less pathogenic • Duration of HIV-2 infection is shorter • Mother To Children Transmission of HIV is relatively rare with HIV-2
- 11. “THE VIRAL GENOME” Icosahedral (20-sided), enveloped virus of the lentivirus subfamily of retroviruses. Retroviruses transcribe RNA to DNA. Two viral strands of RNA found in core surrounded by protein outer coat. Outer envelope contains a lipid matrix within which specific viral glycoproteins are imbedded. These knob-like structures responsible for binding to target cell.
- 12. Modes of HIV/AIDS Transmission ◼ Blood products ◼ Semen ◼ Vaginal fluids ◼ Breast Milk Through Bodily Fluids
- 13. IntraVenous Drug Abuse Sharing Needles Without sterilization Increases the chances of contracting HIV Unsterilized blades
- 14. Through sex (Unprotected )Intercourse Oral Anal From mother to baby Before Birth During Birth
- 15. Transmission of HIV HIV is not transmitted by • Public baths • Handshakes • Work or school contact • Using telephones • Sharing cups, glasses, plates, or other utensils • Coughing, sneezing • Insect bites • Touching, hugging • Water, food • Kissing
- 16. NATURAL COURSE OF HIV/AIDS Stage 1 - Primary Short, flu-like illness - occurs one to six weeks after infection Mild symptoms Infected person can infect other people
- 17. Stage 2 - Asymptomatic Lasts for an average of ten years This stage is free from symptoms There may be swollen glands The level of HIV in the blood drops to low levels HIV antibodies are detectable in the blood
- 18. Stage 3 - Symptomatic The immune system deteriorates Opportunistic infections and cancers start to appear.
- 19. Stage 4 - HIV AIDS The immune system weakens too much as CD4 cells decrease in number.
- 20. Opportunistic Infections associated with AIDS CD4<500 Bacterial infections Tuberculosis (TB) Herpes Simplex Herpes Zoster Vaginal candidiasis Hairy leukoplakia Kaposi’s sarcoma
- 21. Opportunistic Infections associated with AIDS CD4<200 Pneumocystic carinii Toxoplasmosis Cryptococcosis Coccidiodomycosis Cryptosporiosis Non hodgkin’s lymphoma
- 22. CD4 <50 Disseminated mycobacterium avium complex (MAC) infection Histoplasmosis CMV retinitis CNS lymphoma Progressive multifocal leukoencephalopathy HIV dementia
- 23. TB & HIV CO-INFECTION TB is the most common opportunistic infection in HIV and the first cause of mortality in HIV infected patients (10-30%) 10 million patients co-infected in the world. Immunosuppression induced by HIV modifies the clinical presentation of TB : Subnormal clinical High rate of treatment failure and relapse (5% vs < 1% in HIV)
- 24. Blood Detection Tests HIV enzyme-linked immunosorbent assay (ELISA) Screening test for HIV Sensitivity > 99.9% Western blot Confirmatory test Speicificity > 99.9% (when combined with ELIZA) HIV rapid antibody test Screening test for HIV Simple to perform Absolute CD4 lymphocyte count Predictor of HIV progression Risk of opportunistic infections and AIDS when <200 HIV viral load tests Best test for diagnosis of acute HIV infection Correlates with disease progression and response to HAART
- 25. Oral Testing Orasure The only FDA approved HIV antibody. As accurate as blood testing Draws blood-derived fluids from the gum tissue. NOT A SALIVA TEST!
- 26. HAART = highly active anti-retroviral treatment
- 27. Antiretroviral Drugs (HAART) Nucleoside Reverse Transcriptase inhibitors AZT (Zidovudine) Non-Nucleoside Transcriptase inhibitors Viramune (Nevirapine) Protease inhibitors Norvir (Ritonavir)
- 28. PREVENTION: Five ways to protect yourself? Abstinence Monogamous Relationship Protected Sex Sterile needles New shaving/cutting blades