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HIV & AIDS

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  1. HIV & AIDS Lecturer: Dr. A. van Graan Acknowledgements: Hilary Woodley

  2. HIV & AIDS • Human immunodeficiency virus (HIV) • Acquired immunodeficiency syndrome (AIDS) • Primary infection with HIV is the underlying cause of AIDS

  3. Incidence & Prevalence WHO Report

  4. Incidence & Prevalence UN GLOBAL SUMMARY OF THE AIDS EPIDEMIC update: DECEMBER 2005

  5. Incidence & Prevalence Total: 40.3 million (36.7-45.3) UNAIDS/WHO

  6. Incidence & Prevalence Total: 4.9 million (4.3-6.6) UNAIDS/WHO

  7. Incidence & Prevalence Total: 3.1 million (2.8-3.6) UNAIDS/WHO

  8. Incidence & Prevalence UN GLOBAL SUMMARY OF THE AIDS EPIDEMIC update: DECEMBER 2005

  9. Incidence & Prevalence • Sub-Saharan Africa has just over 10% of the world’s population • more than 60% of all people living with HIV • 2005, an estimated 3.2 million in the region became newly infected • 2.4 million adults and children died of AIDS • young people aged 15–24 years 4.6% of women and 1.7% of men were living with HIV in 2005 WHO Report

  10. Incidence & Prevalence

  11. Incidence & Prevalence UN GLOBAL SUMMARY OF THE AIDS EPIDEMIC update: DECEMBER 2005

  12. Incidence & Prevalence • HIV prevalence among pregnant women: • highest levels to date: 29.5% (DOH in 2004) • women aged 25–34 years - more than 1 in 3 estimated HIV+ • women aged 20–24 years - almost 1 in 3 was infected • KwaZulu-Natal 40% • Eastern Cape, Free State, Gauteng, Mpumalanga and North West provinces 27% - 31% • late teens (15–19 years) 15 - 16% since 2000 • 20–24 year-old 28% - 31% in 2000–2004 (Department of Health, 2005)

  13. Incidence & Prevalence UN GLOBAL SUMMARY OF THE AIDS EPIDEMIC update: DECEMBER 2005

  14. Incidence & Prevalence • death registration data has shown that deaths among people: • 15 years of age and older increased by 62% in 1997–2002 • 25–44 years more than doubling • nearly 2.9 million death notification certificates more than 1/3 of all deaths were among people in that age group (Statistics SA, 2005)

  15. HIV & AIDS • HIV invades the genetic core of the CD4+ or T-helper lymphocyte cells, the principal agents involved in protection against infection

  16. HIV & AIDS • CD4+ cell count in blood is the common laboratory test used • other distinct compartments contain virus and evolve separately: • semen • vaginal secretions • the lymph system and • the central nervous system

  17. HIV & AIDS • HIV infection causes a progressive depletion of CD4+ cells, which eventually leads to: • immunodeficiency • constitutional disease • neurologic complications • opportunistic infections and • neoplasms

  18. HIV & AIDS • HIV can be transmitted via: • blood • semen • presemenal fluid • vaginal fluid • breast milk and • other body fluids that contain blood

  19. HIV & AIDS • HIV can be transmitted via: • cerebrospinal fluid surrounding the brain and spinal cord • synovial fluid surrounding bone joints and amniotic fluid surrounding a foetus are other fluids that can transmit HIV

  20. HIV & AIDS • HIV can NOT be transmitted via: • saliva • tears and • urine • contact-touching • hugging or kissing • through using the same plates, silverware or drinking glasses

  21. HIV & AIDS • most common way HIV is transmitted is via: • blood and semen during unprotected anal or vaginal intercourse with an HIV-infected person • risk of transmission through oral sex is considered low but not risk-free

  22. HIV & AIDS • Transmission can also occur by: • sharing of contaminated needles • injection of contaminated blood products • by transfer from an infected mother to her baby before or during birth • through breast-feeding

  23. HIV & AIDS • All persons should use universal precautions to protect both themselves and others when working with body fluids

  24. HIV & AIDS • Two types of HIV: • HIV-1: Majority of HIV infection worldwide • HIV-2: West Africa • HIV-l mutates readily and has different strains, which have many subtypes and groups and are found distributed unevenly throughout the world

  25. HIV & AIDS • HIV-1 strains • Group M (major) – prevalent – 90% of cases • Group O (outlier) – rare and quite diverse • Group N (new) – recently described in Cameroon • HIV-1 subtypes (clades) – A to J • Initial epidemic in South Africa: B  C • The reason for the genetic diversity is related to inherent potential of virus to mutate

  26. Manifestations & stages • After exposure and transmission of HIV into the host • HIV spreads throughout the body and blood CD4+ cell counts fall dramatically

  27. Manifestations & stages • An immune response follows • CD4+ cells can return to almost normal and • virus in the blood falls to an undetectable level

  28. Manifestations & stages • During this period of clinical latency • CD4+ cells de­crease to below a level at which increased risks of opportunistic infections occur • Untreated, HIV eventually replicates at 800 billion virus particles per day

  29. Manifestations & stages • Both the World Health Organization and the Centre’s for Disease Control have set criteria for defining AIDS • The WHO staging is clinical and useful in resource poor areas where laboratory facilities are not always available

  30. WHO Clinical system Stage 1 - 4 Includes functional status CDC Clinical + Lab Stage A – C + 1 – 3 Does not include functional status Manifestations & stages

  31. Manifestations & stages Krause 11th ED • Four stages of the disease have been characterized: (1) acute HIV infection (2) asymptomatic chronic HIV infection (3) symptomatic HIV infection (4) AIDS or advanced HIV

  32. Lymphadenopathy www.aids-hiv.cz/ diagnostika.htm

  33. Manifestations & stages Krause 11th ED • Acute human immunodeficiency virus (HIV) infection: • 4- to 7 -week period immediately after infection • viral replication is rapid

  34. Manifestations & stages Krause 11th ED Acute human immunodeficiency virus (HIV) infection: • 30 - 60% of newly infected persons develop an acute syndrome with: • Fever • Malaise • Lymphadenopathy syndrome (LAS) • Pharyngitis • Headache • Myalgia and sometimes rash which may last for a week to a month

  35. Manifestations & stages Krause 11th ED Acute human immunodeficiency virus (HIV) infection: • The time period between the initial HIV infection and seroconversion (the development of HIV antibodies) varies from 1 week to several months or more • Once antibodies to HIV appear in the blood, individuals with and without symptoms will test positive for HIV • Viral load is extremely high, and individuals are very infectious at this time.

  36. Manifestations & stages Krause 11th ED Asymptomatic HIV stage: • few, if any, noticeable symptoms occur • last from a few months to as long as 10 years • Subclinical changes have been reported: • decrease in lean body mass without apparent total body weight change • vitamin B12 deficiency and • increased susceptibility to food borne and waterborne pathogens

  37. Manifestations & stages Krause 11th ED Symptomatic HIV occurs when symptoms appear (CDC Category B) • symptoms may include: • fevers • sweats • skin problems • fatigue or • other symptoms that are not AIDS-defining • a decline in nutrient status or body composition may also occur

  38. Manifestations & stages Krause 11th ED AIDS, or advanced HIV disease: • the diagnostic term reserved for those persons with at least one well-defined, life-threatening clinical condition that is clearly linked to HIV-induced immunosuppression (CDC Category C)

  39. Manifestations & stagesCD4 cell counts and associated conditionsKrause 11th Ed, Table 41.1

  40. Manifestations & stagesCD4 cell counts and associated conditionsKrause 11th Ed, Table 41.1

  41. Manifestations & stagesCategories for ChildrenKrause 11th Ed, Table 41.2

  42. Clinical categories CD4+ cell count categories A Asympt. or PGL B Symptomatic (not A or C) C Aids indicator diseases 1 > 500/mm3 A1 B1 C1 2 200–499/mm3 A2 B2 C2 3 < 200/mm3 A3 B3 C3 CDC 1993

  43. Manifestations & stagesCDC 1993Krause 11th Ed, Box 41.1

  44. Opportunistic Infections and Other Complications • Opportunistic infections with: • bacteria • fungi • protozoa or • viruses are common in this population