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HIV (AIDS)

HUMAN IMMUNODEFICIENCY VIRUS

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HIV (AIDS)

  1. 1. HIV/AIDS DR MD TIPU SULTAN Associate Professor Department of Microbiology Chittagong Medical College 1
  2. 2. 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 2
  3. 3. 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 3
  4. 4. 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 4
  5. 5. “The greatest single public health challenge that humanity has ever faced.” Dr. Robert Lue, Harvard University 5
  6. 6. HIV/AIDS Historical Perspective 1979 CDC reported unexplained PCP in 5 previously healthy, homosexual men  CDC reported Kaposi’s sarcoma in 26 previously healthy, homosexual men  Initially,then the disease was named as GRID (Gay related immune deficiency)  1981- AIDS was recognized as separate disease 1981-1982  Increased association with IV drug use, recipients of blood transfusions, hemophiliacs 6
  7. 7. HIV/AIDS Historical Perspective 1983  Virus isolated.Then it was 1st named as LAV(Lymphadenopathy associated virus) 1984  Virus was named as HTLV-III (Human T-cell Lymphotrophic Virus) 1985  Virus was named as ARV (AIDS related Virus) 1986  Virus was named as HIV by the International committee on the taxonomy of viruses 7
  8. 8. HIV/AIDS Historical Perspective 1985  ELISA test developed Today:  Broad spectrum of disease  Asymptomatic infection  Clinical latency  Advanced disease (AIDS)  Clearly sexually transmitted, and transmitted through blood products 8
  9. 9. In Bangladesh, HIV positive cases was 1st detected in 1989 in Chittagong 9
  10. 10. Global summary of the HIV and AIDS epidemic Number of people living with HIV Total 39.4 million (35.9– 44.3 million) 37.2 million (33.8–41.7 million) Adults Women 17.6 million (16.3– 19.5 million) Children under 15 years 2.2 million (2.0– 2.6 million) People newly infected with HIV Total 4.9 million (4.3 – 6.4 million) Adults 4.3 million (3.7 – 5.7 million) Children under 15 years 640 000 (570 000 – 750 000) AIDS deaths Total 3.1 million (2.8 – 3.5 million) Adults 2.6 million (2.3 – 2.9 million) Children under 15 years 510 000 (460 000 – 600 000) The ranges around the estimates in this table define the boundar within which the actual numbers lie, based on the best avail ble information. ies a 00003-E-1 – December 2004 10
  11. 11. HIV/AIDS BANGLADESH SITUATION, END 2012 Total HIV-positive people - 2384 People living with AIDS - 676 Deaths due to AIDS - 263 Sources:DGHS, MOH&FW, December 1, 2012. WHO: Estimated to have 13,000 to 21,000 people are likely to be infected with HIV. 11
  12. 12. Prevalence Among High Risk Population in Bangladesh •The highest prevalence is among IDUs 4%. • Street and Hotel based CSWs– 0.2% each. •Brothel based CSWs– 0.2% to 0.7% • MSMs – 0.2% 12
  13. 13. Important Bangladesh was the first among the SAARC Countries to take the threat of HIV epidemic seriously & initiated a national response in 1985. According to WHO, Bangladesh is one of the fortunate 111 countries where the infection rate has not yet reached 1 adult / 1000. 13
  14. 14. Retrovirus RNA virus Enveloped Reverse transcriptase enzyme HIV, HTLV 14
  15. 15. Unique Characteristics of Retroviruses Enveloped and encloses a capsid containing two copies of RNA genome. RNA-dependent DNA polymerase (reverse transcriptase) and integrase enzymes are carried in the virion. Replication proceeds through a DNA intermediate, termed the provirus. The provirus integrates randomly into the host chromosome and becomes a cellular gene. Simple retroviruses encode gag, pol, and env genes. Complex viruses also encode accessory genes (e.g., tat, rev, nef, vif, vpu for HIV). Virus assembles and buds from the plasma membrane. Final morphogenesis of HIV requires protease cleavage 15 of gag and gag-pol polypeptides.
  16. 16. HIV Structure HIV is composed of three main layers:  Envelope  Viral Matrix  Core Image from http://www.brown.edu/Courses/Bio_160/Projects1999/hiv/images/Virion2.jpg 16
  17. 17. HIV structure 17
  18. 18. Types of HIV HIV 1 Subtypes- A to I and O Subtype A & D – found in sub Sahara Africa  Subtype B – found in US & Canada  Subtype C – found in South Africa & India  Subtype E – found in south east Asia  Subtype G & H - found in Russia & Central Africa  Subtype I – found in Cyprus  HIV 2 18
  19. 19. 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 19
  20. 20. HIV-1 and HIV-2 • HIV-2 is less easily transmitted • HIV-2 is less pathogenic • Duration of HIV-2 infection is shorter 20
  21. 21. Important antigens: 1) Group-Specific Antigens p17: inner surface p24: nucleocapsid p9: nucleocapsid associated with RNA GAG gene 21
  22. 22. 2) Type -Specific envelope glycoprteins gp120 & gp41 ENV gene 22
  23. 23. 3. Enzymes • Polymerase (reverse transcriptase) • Integrase • Protease • POL gene 23
  24. 24. Transmission of HIV 24
  25. 25. Transmission of HIV HIV is transmitted by • Direct contact with infected blood • Sexual contact: oral, anal, or vaginal • Direct contact with semen or vaginal and cervical secretions • HIV-infected mothers to infants during pregnancy, delivery, or breastfeeding 25
  26. 26. HIV enter the body via the bloodstream either during sexual intercourse needle drug abuse transfusion with contaminated blood products or via the placenta During sexual intercourse, HIV 1 infects Langerhans dendritic cells in the epithelium and these can then travel to lymph nodes. On injection of virus into blood, the virus is likely to infect dendritic and other monocyte-macrophage lineage cells. 26
  27. 27. Blood Up to 10,000 infectious particles per ml Shared drug/drug-injecting equipment  needles, syringes
  28. 28. Blood Transfusions  plasma, whole blood, platelets  clotting factors (decreased since 1985) 28
  29. 29. Sexual Contact STD’s increase risk of transmission  epidemiological  exposed trend to one, may mean exposed to others  inflammation make person more vulnerable to HIV invasion
  30. 30. Sexual Contact Intercourse (without barrier)  anal:  vaginal:  oral:
  31. 31. Sexual Contact Semen: only 10-50 infectious virons per ml  artificial insemination a risk Vaginal/cervical secretions: less than 1 viron per ml
  32. 32. Perinatally In utero (maternal-fetal circulation)  HIV crosses the placenta During delivery Breast-feeding  low incidence
  33. 33. Risk Factors What you do not who you are 33
  34. 34. High risk groups 1) 2) 3) 4) 5) homosexual/bisexual men IV drug use/abuse hemophiliacs sex partners in abuse groups infants of above groups 34
  35. 35. Transmission of HIV HIV is not transmitted by • Coughing, sneezing • Insect bites • Touching, hugging • Water, food • Kissing • Public baths • Handshakes • Work or school contact • Using telephones • Sharing cups, glasses, plates, or other utensils 35
  36. 36. Important properties: •HIV primarily infects CD4 T cells and cells of the macrophage lineage •Monocytes •Macrophages CD4 proteins on their surface •Dendritic cells (skin) •Microglial cells (CNS) 36
  37. 37. Which cells does HIV-1 infect? Identification of molecular targets. Lymphocytes Receptor: CD4+, Coreceptor: CXCR4 Macrophages: Receptor: CD4+ Coreceptor: CCR5 Dendritic cells (DC): DC recognized by gp120 on HIV DC: primary target of mucosal infection! DC present HIV antigen to resting lymphocytes Microglial cells: Receptor: Galactosyl ceremide 37
  38. 38. Replication 38
  39. 39. HIV chemokine CD4 CD4 CCR5 CCR5 CD4 Mutant CCR5 macrophage Chemokine receptors are necessary co-receptors along with CD4 antigen 39
  40. 40. Provirus 40
  41. 41. 41
  42. 42. Pathogenesis 42
  43. 43. 43
  44. 44. Reduction in the numbers of CD4 T cells may result from HIV-infected cytolysis, cytotoxic T-cell immune cytolysis. The increased release of virus into the blood as the numbers of CD4 cells decrease gives development of symptoms. Macrophages may be spared the cytolytic action of HIV because they express less CD4 than T cells. 44
  45. 45. Macrophage-lineage cells express both the CCR5 & CXCR4 chemokine receptors and can be infected by M-& L-tropic HIV. The virus reaches the lymph node within 2 days of infection and there the CD4 T cells are infected. Macrophages are persistently infected with HIV and are probably the major reservoirs. Continuous replication of the virus occurs in the lymph nodes, with subsequent release of the virus and infected T cells into the blood 45
  46. 46. Pathogenesis(contd) The hallmark of pathogenesis is the profound immunodeficiency, primarily affecting CMI HIV infect any cells bearing CD4 receptor -Severe depletion of CD4+ T-cell -Impairment of function of surviving CD4+ T-cell 46
  47. 47. Pathogenesis(contd) Monocyte/Macrophage abnormalitiesRelatively resistant to cytolytic effect of HIV and the consequences are *Acts as reservoir of virus *Transport the virus to different part of the body B-cell abnormalitiesPolyclonal activation leads to hypergammaglobulinaemia Unable to mount antibody response to a new antigen due to lack of T cell help 47
  48. 48. Steps for pathogenesis of HIV: rapid early dissemination of virus seeding of virus in lymphoid tissue partial host immune responses that downregulates viral replication sequestration of extracellular virus into germinal center of lymph nodes chronic activation of T lymphocytes and secretion of immune system activating cytokines 48
  49. 49. Steps for pathogenesis of HIV:(cont.) destruction of lymphoid tissue escape of viral elements into peripheral blood cells direct killing of CD4 cells 49
  50. 50. Potential mechanism of CD4 T cell depletion/dysfunction Direct HIV mediated cytopathic effect HIV mediated formation of syncytia Virus specific immune response Autoimmune mechanism Anergy-Inappropriate cell signaling (gp120-CD4 interaction Superantigen Apoptosis 50
  51. 51. Three mechanisms by which HIV evades immune system 1. Integration of viral DNA into host cell DNA resulting in a persistent infection. 2. A high rate of mutation of the env gene. 3. Production of the Tat and Nef proteins that downregulate class I MHC proteins required for cytotoxic T cells to recognize and kill HIV-infected cell 51
  52. 52. Progression of HIV in the Body Image from http://www.hivaidssearch.com/hiv-aids-links.asp?id=936 52
  53. 53. Initially, large burst of virus production & viremia, which corresponds to the occurrence of a mononucleosis-like syndrome. 53
  54. 54. Virus levels in the blood decrease during a clinically latent period, but viral replication continues in the lymph nodes. 54
  55. 55. Late in the disease, virus levels in the blood increase, CD4 levels are significantly decreased. the structure of the lymph nodes is destroyed, and the patient becomes immunosuppressed 55
  56. 56. Clinical Manifestations 56
  57. 57. Initial infection Fever and other flu-like symptoms  lympadenopathy 57
  58. 58. Prolonged Asymptomatic Infection person is HIV+ but asymptomatic  lasts for several years (subclinical)  viral  replication occurring up to 10 billion virons per day  chronic lymphadenopathy 58
  59. 59. Early Symptomatic Disease CD4 counts drop to 500-600 cells/ml symptoms: recurrent fever, night sweats, malaise, headache physical findings: lymphadenopathy, spleen enlarged, rash, weight loss 59
  60. 60. Opportunistic Infection infection by a pathogenic organism  that is normally present but not harmful  becomes infectious in immunocompromised person 60
  61. 61. AIDS AIDS vs. HIV positive 61
  62. 62. Average time between infection and AIDS was 10 years  time has increased with new protease inhibitors
  63. 63. Symptoms of HIV - “classic 6” − − − − − − fatigue/malaise lymphadenopathy weight loss fever night sweats diarrhea 63
  64. 64. AIDS CD4 count less than 200/mm majority of manifestations due to opportunistic infections due to immunosuppression  rather than direct injury by virus  It is a condition in which common curable infectious disease turned into incurable form due to immunodeficiency, caused by HIV infection 64
  65. 65. Clinical Course of HIV/AIDS HIV Infection Virus deposited on mucosal surface  Acute infection (mono-like symptoms)  Viral dissemination  HIV-specific immune response  Replication of virus  Destruction of CD4+ lymphocytes  Rate of progression is correlated with viral load  Latent Period 65
  66. 66. Clinical Course of HIV/AIDS AIDS  Immunologic dysregulation  Opportunistic infections and cancers  Risk of infections is correlated with number of CD4+ lymphocytes  Average patient with AIDS dies in 1-3 years 66
  67. 67. WHO classification of clinical stages of infection Children – Three stages Adults & Adolescents – Four stages 67
  68. 68. WHO Clinical stage I in Children Asymptomatic Generalized lymphadenopathy 68
  69. 69. WHO Clinical stage II in Children Unexplained chronic diarrhoea Severe persistent or recurrent candidiasis outside the neonatal period Weight loss or failure to thrive Persistent fever Recurrent severe bacterial infection 69
  70. 70. WHO Clinical stage III in Children AIDS – defining opportunistic infections Severe failure to thrive Progressive encephalopathy Malignancy Recurrent septicaemia or meningitis 70
  71. 71. WHO Clinical stage I in Adults & Adolescents Asymptomatic Persistent generalized lymphadenopathy Performance scale 1: asymptomatic, normal activity 71
  72. 72. WHO Clinical stage II in Adults & Adolescents Weight loss, <10% of the body weight Minor mucocutaneous manifestations Herpes Zoster within the last 5 years Recurrent upper respiratory tract infections Performance scale 2: symtomatic, normal activity 72
  73. 73. WHO Clinical stage III in Adults & Adolescents Weight loss, >10% of the body weight Unexplained chronic diarrhoea >1 month Unexplained prolonged fever (interminant or constant) >1 month Oral candidiasis (thrush) Pulmunary tuberculosis Severe bacterial infection Performance scale 3: bed-ridden, >50% of the day during the last month 73
  74. 74. WHO Clinical stage IV in Adults & Adolescents HIV wasting syndrome Pneumocystis carinii pneumonia Toxoplasmosis of the brain Cryptosporidiosis with diarrhoea Cryptococcosis, extra pulmonary Atypical mycobacteriosis Salmonella septicaemia Progressive multifocal leukoencephalopathy Performance scale 4: bed-ridden, >50% of the day during the last month 74
  75. 75. WHO Clinical stage IV in Adults & Adolescents (Cond.) Cytomegalovirus disease of an organ other than liver, spleen or lymph nodes. Hepes simplex virus infection, mucateneous >1 month, or visceral any duration Progressive multifocal leukoencephalopathy Any disseminated endemic mycosis (I.e. histoplasmosis, coccidiodomycosis) Candidiasis of the oesophagus, trachea, bronchi or lungs Lymphoma 75
  76. 76. AIDS in Children 76
  77. 77. AIDS in Children Infants who are seropositive at 18 months are infected Infants progress to AIDS more rapidly, usually in 3 years HIV testing during pregnancy 77
  78. 78. AIDS in Children Transmission is usually perinatal 100% are HIV+ at birth 25% are actually infected 1 in 4 chance of passing on virus  less if mother is treated 78
  79. 79. Opportunistic infections − pneumocystic carinii pneumonia (PCP) − candida esophagitis -- cryptococcal meningitis − chr. mucocutaneous Herpes simplex -- toxoplasmosis − disseminated Mycobacterium avium or kansasii − disseminated CMV -- chronic Cryptosporidial enterentis − disseminated stronyoidiasis -- Histoplasmosis − bronchopulmonary candidiasis -- Isosporiasis -- disseminated TB -- disseminated Coccidioidomycosis − recurrent Salmonella septicemia 79
  80. 80. Opportunistic tumors − Kaposi’s sarcoma − primary CNS lymphoma − certain high-grade B-cell lymphoma 80
  81. 81. Diagnosis 81
  82. 82. Laboratory diagnosis Evidence of HIV infection Virus isolation Measurement of viral nucleic acid Detection of viral antigen Detection of viral antibody Recognition of immunodeficiency CD4+ T cell count Recognition of AIDS related disease 82
  83. 83. 1.Virus isolation : HIV can be cultured from lymphocytes in peripheral blood. (Co-culture of patients T-cell with Leukaemic or mitogen stimulated CD4+ Tcell line). 83
  84. 84. 2. Detection of viral Nucleic Acid : By RT-PCR Branched-chain DNA To detect viral RNA in clinical specimens. 84
  85. 85. Viral RNA Assay Dynamics of HIVbillions of viruses produced and destroyed daily  Rate of viral replication stabilizes after primary infection at a “set point: in each individual. (102-106 HIV RNA copies/ml) of plasma  Remains stable over months and possibly years 85
  86. 86. Viral RNA Assay (cont.) Viral RNA - indirect reflection of the number productively infected cells in the body as a whole Appears to be a proportion between plasma viral RNA and the amount of viruses in the fixed lymphoid tissues  Set point associated with the rate of disease progression and time of death  HIV RNA levels appear more predictive of progression than CD counts  4 86
  87. 87. 87
  88. 88. Therefore utility of HIV RNA assays include:  Assessing baseline status in newly diagonal HIV patient  Assessing response to therapy  Assessing development of resistance to current therapy  Typically 109-1010 virions are produced daily  Reductions in plasma viremia correlates with increased CD4 cells and AIDS-free survival 88
  89. 89. 3. Detection of HIV Antigen HIV antigen tests detect the presence of HIV in blood P24 antigen tests measure one of the proteins found in HIV The antigen often becomes undetectable after antibodies develop and may reappear at low levels intermittently during the period of clinical latency and in some people as infection progresses 89
  90. 90. 3. Detection of viral p24 Antigens: Low levels of circulating HIV p24 antigen can be detected in the plasma by ELISA soon after infection. usually disappeared by 8-10 weeks after exposure. It can be a useful marker in individuals who have been infected recently but have not had time to mount an antibody response 90
  91. 91. 4. Detection of antibody measuring antibodies by ELISA. HIV antibody may develop slowly, 4-8 wks in most patients. A positive test in a serum sample must be confirmed by a repeat test If the repeat ELISA test is reactive, a confirmation test is performed. By immunofluorescence, Western blot technique or Line immunoblot assay 91
  92. 92. Detection of IgG antibody to envelope components(gp120 and its subunits) This is the most commonly used marker of infection The routine tests used for screening are based on ELISA techniques, which may be confirmed with Western blot assays. Up to 3 months may elapse from initial infection to antibody detection (serological latency, or window period). IgG antibody to p24 (anti-p24) This can be detected from the earliest weeks of infection and through the asymptomatic phase. It is frequently lost as disease progresses. 92
  93. 93. Window period: Early in infection when the blood of an infected person can contain HIV but antibodies are not detectable. Seroconversion: Development of evidence of antibody response to a disease. Viral Load: The amount of HIV in the blood. 93
  94. 94. “Window Period”  A period of 4-6 weeks after HIV exposure when antibodies to HIV are not detectable in the blood  A person at high risk who initially tests negative should be retested at 3 months to confirm diagnosis 94
  95. 95. “Window Period” Time between infection with HIV and detection of HIV antibodies in the serum (time to seroconvert) “Seropositive”: detectable antibodies to HIV in the serum  person becomes infectious within 2 weeks of exposure
  96. 96. Seroconversion : detectable antibody response96
  97. 97. Tests which detect antibodies Enzyme linked immunosorbent assay (ELISA) Particle agglutination test (PAT) Screening tests Latex agglutination test Indirect fluorescence antibody test (IFAT) Radio immunoprecipitation assay (RIA) Immunochromatographic test (ICT) Line immunoblot assay (LIA) Western Blot assay (WB) Confirmatory tests 97
  98. 98. ELISA for HIV antibody ELISA false-positive: immunologic abnormalities neoplasms multiple transfused pregnancy Microplate ELISA for HIV antibody: colored wells indicate reactivity 98
  99. 99. Western Blot HIV-1 Western Blot Lane1 : Positive Control Lane 2 : Negative Control Sample A: Negative Sample B: Indeterminate Sample C: Positive 99
  100. 100. Western blot to be considered positive At least two bands including p24, gp41, or gp120/gp160 should be present. (antibodies to HIV proteins of specific molecular weight can be detected) Western blot is confirmatory test for HIV antibody detection, because the test can detect all the HIV-specific antibodies according to their molecular weight 100
  101. 101. 101
  102. 102. 5. CD4:CD8 cell count: Absolute number of CD4+ cell and ratio of helper cell to inducer cell are abnormally low. 102
  103. 103. Selection of the HIV Test Is site-specific based on:  National/local policies  Availability of supplies and laboratory support  Availability of trained personnel  Evaluation of specific tests in the country  Costs 103
  104. 104. The Testing Process • Test sample • Blood, saliva, urine • Process the sample, on-site or in lab • Obtain results • Keep confidential • Method determined by clinic protocols and client • Provide results to client • Provide post-test counselling, support and 104
  105. 105. Guiding Principles for Counselling and Testing  Information on HIV status kept private  Information shared only with providers directly involved in care—and only on a “need to know” basis  Medical records kept in safe place 105
  106. 106. Guiding principles (contd.) • Pre-test Group education • Informed Consent • Identifies: • Purpose of testing and processes involved • Benefits and risks of testing • Available treatment and support • Respects • Individual’s autonomy and right to confidentiality 106
  107. 107. Counseling and Testing as an Entry Point to MCH/HIV Prevention Community action to reduce Stigma & discrimination Post - delivery care and support Safer infant feeding Primary prevention of new HIV infection VCT and its links with other services Prevention of unintended pregnancy Safer obstetric practices Antiretroviral prophylaxis 107
  108. 108. Pre-test Information  Group education in  Relevant HIV and AIDS information  Transmission and prevention  STIs and HIV  HIV testing and test result interpretation  Implications of both positive and negative results  Benefits and risks of HIV testing  Individual counselling and risk assessment  Identification of supportive services  Privacy and Confidentiality 108
  109. 109. Post-Test Counselling Provide the woman with her HIV test result Help her understand what the result means Provide support, information, and referral when indicated Encourage risk- reducing behavior Encourage disclosure and partner testing 109
  110. 110. Post-Test Counselling  HIV-negative  Review window period if indicated • Prevent future infection • Review risk with new infection • Educate partner and encourage partner testing 110
  111. 111. Post-Test Counselling  HIV-positive result • Clarify understanding • Acknowledge feelings • Review benefits of knowing HIV status • Address immediate concerns • Schedule follow-up visit • Provide support ,name and telephone number of contact person 111
  112. 112. Diagnosing HIV in HIVExposed Infant  ARV prophylaxis reduces but does not eliminate Mother to child transmission of HIV infection  Since maternal antibodies cross the placenta, antibody testing is not recommended prior to 18 months of age  Infants who are breastfeeding require additional testing 6 weeks after complete cessation of breastfeeding  HIV viral assays are not used for diagnosis of HIV infection in the infant 112
  113. 113. Summary • Pre-test information, HIV testing, and post-test counselling should be available to all pregnant women • The need for pre-test counselling should be determined on an individual basis • The healthcare provider and the facility must maintain confidentiality of HIV status. • Partner testing and couples counselling should be encouraged 113
  114. 114. Summary (contd.) Rapid tests with same day results are the recommended procedure for most settings. Infant diagnosis is complex but important for clinical management • Standard diagnosis is done by antibody test at 18 months • Earlier diagnosis is possible with PCR testing Post-test counseling is important for all women, including HIV-negative women 114
  115. 115. Disclosure • Ensure confidentiality • Respect woman’s choices • Encourage partner testing • Review prevention of transmission • Identify support 115
  116. 116. CURRENT TESTING FACILITIES IN BANGLADESH Screening Purposes : Latex agglutination Immunochromatography Particle agglutination ELISA For Confirmation : BSMMU, Dhaka-Western blot Dhaka-Western blot ICDDR,B-Dhaka-Western blot Dhaka-Western blot Medical College-Line immunoassy, ELISA Chittagong Medical College-Line immunoassy, ELISA Sylhet Medical College-Line immunoassy, ELISA AFIP, IEDCR, Dhaka 116
  117. 117. EXISTING DIAGNOSTIC FACILITIES ( CONTD) Screening tests for HIV [ PAT and ELISA ] are also carried out in blood transfusion centres to ensure safe blood transfusion Currently, 98 safe blood transfusion centres are present in our country [ Medical Colleges- 13, Specialized hospitals - 6, District hospitals- 53, CMH- 13, Other big hospital- 10, Red crescent- 3 ] 117
  118. 118. Treatment 118
  119. 119. Types of HIV Drugs Entry inhibitors Reverse Transcriptase inhibitors Integrase inhibitors (On study) Protease inhibitors Assembly & budding inhibitors (On study) 120
  120. 120. Attacking HIV with antiretroviral drugs Protease inhibitors Attachment inhibitors Assembly inhibitors RT inhibitors Integration inhibitors 121
  121. 121. Entry inhibitors Fusion inhibitor Fuzeon (enfuvirtide, or T-20) 122
  122. 122. Reverse Transcriptase Inhibitors Nucleoside reverse transcriptase inhibitors (NsRTIs)  Zidovudine(ZDV, AZT)  Didanosine (ddl)  Stavudine (d4T)  Lamivudine (3TC)  Abacavir (ABC) 123
  123. 123. Reverse Transcriptase Inhibitors(contd) Non - nucleoside reverse transcriptase inhibitors (NsRTIs) Nevirapine (NVP)  Efavirenz (EFZ)   Delavirdine Nucleotide reverse transcriptase inhibitors  (NtRTIs) Tenofovir disoproxil fumarate 124
  124. 124. Protease Inhibitors Indinavir(IDV) - Crixivan Nelfinavir(NFV) - Viracept Ritonavir(RTV) - Norvir Saquinavir(SQV) - Invirase or Fortovase Amprenavir(APV) – Agenerase Lopinavir/Ritonavir(LPV/r) - Kaletra 125
  125. 125. Therapy might be started when PVL is over 10,000. If therapy is in progress, several PVL tests a year monitor the status. If PVL goes up, medication needs to be changed, quite obviously. The goal is to clear detectable virus from the blood in 16-24 weeks. 126
  126. 126. Highly Active Antiretroviral Therapy (HAART) Combination of three or more drugs 127
  127. 127. Why is HIV so hard to treat? 1. HIV-1 and other lentiviruses have the unique property among retroviruses to replicate in nondividing cells. 2. Mutation rate is maximum permissible 3. Latent period of incubation 4. Integration into host genome unpredictable 128
  128. 128. 4 Questions that Need Answers for HIV Therapy When to initiate therapy? Which types of drugs to use? When to change therapy? Which drugs to use when changing therapy? 129
  129. 129. When to Initiate Therapy? 2001 Recommended for patients with RNA > 30,000 copies/ml  CD4 cell counts < 350/µl irrespective of RNA level.  RNA levels 5000-30,000 and CD4 between 350500/µl  130
  130. 130. What Drugs should be Initiated in Newly Diagnosed HIV + Patient? AZT + 3TC + either PI or NNRTI 131
  131. 131. Two strategies to maximize benefits/minimize toxicities: Alternating therapies Combination therapy-demonstrated more beneficial than monotherapy  Decreased emergence of resistance  Decreased risk of toxicity 132
  132. 132. HIV infected Pregnant Female Standard antiretroviral therapy should be used in the HIV infected pregnant female  Possible risk of premature delivery (highest in non-treated individuals) 133
  133. 133. Reduced transmission of HIV from mother to infant Proportion of infants of HIV (+) mothers who acquired HIV 40 30 33 % 20 10 0 8 No ARV With ARV 134
  134. 134. Pediatric Patients with HIV Therapy:   AZT + 3TC + either PI (nelfinavir) or NNRTI (efavirenz) Expanded access of liquid formulations   ddC zalcitabine (from Roche), efavirenz (from Dupont), Kaletra (from Abbott) Not recommended: overlapping toxicities or undesirable effects      Monotherpay d4T and AZT ddC and ddI ddC and d4T ddC and 3TC 135
  135. 135. Reasons to Change Regimen? Plasma HIV RNA levels measured on 2 separate occasions CD4 count (changes in these counts) Remaining treatment options for potency Potential resistance patterns from prior antiretroviral therapies Potential for adherence/tolerance Potential for side effects, drug interactions, possible need to alter concomitant medications 136
  136. 136. 3 Patient Populations Identified as Needing Therapeutic Changing Patients receiving incompletely suppressive therapy (single or double NRTI) with detectable or undetectable plasma viral load Patients who have been on potent combination therapy and whose viremia was initially suppressed to undetectable levels but has again become detectable Patients receiving potent combination therapy and whose viremia was never suppressed to below detectable limits 137
  137. 137. Goal of Therapy Suppressing viremia to below detectable levels as consistently as possible.  Requires a level of commitment to be adherent  even a low level of non-adherence will result in the development of resistance which could render the therapy useless. 138
  138. 138. 139
  139. 139. Prevention 140
  140. 140. Prevention of HIV Infections Vaccines  Pre-clinical work in animals is promising Education, Counseling & Behavior mod.  Worked in the US for homosexual men Free needles for IV drug users  Societal debate Improved blood supply  Greatly decreased risk for hemophiliacs Screening and treating pregnant women  Area where interventions are well accepted 141
  141. 141. Why is HIV so hard to fight? Some antibodies that the body produces actually work to enhance HIV replication. Some antibodies that work to neutralize HIV replication can become enhancing antibodies when the virus mutates. Cells other than helper T-cells can be infected, therefore the virus can colonize many tissues of the body. HIV can kill cells that it doesn’t even infect. 142
  142. 142. Vaccine development is difficult 1. HIV mutates rapidly 2. Not expressed in all cells that are infected & is not completely cleared by the host immune response after primary infection. 3. Protective immunity are not known 4. Vaccine based on attenuated or inactivated HIV or in simian isolates don’t ensure safety against possible vector-induced disease 5. Lack of appropriate animal modal for HIV. 143
  143. 143. AIDS Vaccine Two vaccines on trial AIDSVAX B/B – tested in North America & Amsterdam  AIDSVAX B/E – tested in Thailand  Each mixed the surface proteins (gp120) from two strains of HIV 144
  144. 144. New vaccines on human trial tgAAC09 – begun in Belgium Single shot vaccine Uses Targeted Genetics ‘ rAAV (recombinant adeno associated viral vector) Technology 145
  145. 145. New DNA vaccines on human trial Vaccine - ADVAX Vaccine is tailored for C strain of HIV Worked by The Aron Diamond AIDS ResearchCenter & International AIDS Vaccine initiative Trail in New York & Rochester Developed on synthetic DNA based on the genetic material available Safe to use 146
  146. 146. SURVEILLANCE SYSTEM IN BANGLADESH Surveillance is carried out in phases. Currently 4th round of HIV surveillance has been done : -Surveillance on high risk population -Surveillance on mass population No case has been detected on mass population So emphasis should be given on high risk population. 147
  147. 147. MOST PRESSING ISSUES IN HIV/AIDS CONTROL MEASURE IN BANGLADESH High numbers of migrant workers Low socio-economic condition & illiteracy High prevalence rate of STI among sex workers Unsafe sex practice by sex workers Sharing of needles by the IDUs 148
  148. 148. A Short Preview Of The Existing Guideline On HIV/AIDS And STD Related Issues : The government of Bangladesh has Formulated Guidelines On The Following Specific Areas Related To HIV/AIDS : Epidemiological surveillance, Testing policy, Infection management, Counseling , Safe blood transfusion , Education , Information , Awareness development , Promotion of preventive measures , Social science and behavioral research , Clinical vaccine trial , Ethical and legal aspects 149
  149. 149. Thank you 150

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HUMAN IMMUNODEFICIENCY VIRUS

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