Hiv And Aids

HIV and AIDS Acquired Immunodeficiency Syndrome Disease caused by an infectious agent: a retrovirus 1

HIV and AIDS an infectious agent In Los Angeles 1967-1978 only two cases of Pneumocystis carinii pneumonia

• 1979 - 5 cases of Pneumocystis carinii All Homosexual

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HIV and AIDS an infectious agent – Kaposi’s Sarcoma Early 1981 MMWR: 5 cases of Kaposi’s sarcoma Hitherto: rare • 1981 - 26 cases of Kaposi’s sarcoma • Young • San Francisco and New York

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HIV and AIDS Two rare diseases in the gay community linked to

IMMUNOSUPPRESSION OPPORTUNISTIC INFECTIONS Also Lymphadenopathy Hodgkin’s Lymphoma 4

HIV and AIDS

Candida infections are common with AIDS, but most often appear as oral thrush, which is a nuisance but not life-threatening. Disseminated infections are 5 uncommon, but here is a

HIV and AIDS Little in common but: • Young • White • Male • Large towns • Homosexual community But not all gay men got the disease 6

HIV and AIDS Distinguishing characteristics

• Clusters of infected men • Apparent concentration within sexually interactive groups • High numbers of sex partners Suggests an infectious agent 7

HIV and AIDS More evidence for an infectious agent:

• Different ways of getting a similar syndrom • Blood transfusions • Intravenous drug use • Hemophilia (clotting factor) Female sex partners of AIDS-positive IV drug users and hemophiliacs Not just in the Gay community

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HIV and AIDS Obvious agent: A virus……that is now in the blood supply Primary route of transmission: Sex AIDS is a sexually-transmitted disease 9

AIDS • AIDS is currently defined in persons Definition older than 13 years as the presence of one of 25 conditions indicative of severe immunosuppression • HIV infection in an individual with a CD4+ cell count of <200 cells per cubic mm of blood. • AIDS is therefore the end point of an infection that is continuous, progressive and pathogenic • With the prevalence of HIV in the developing world, HIV and its

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AIDS Approximately 8500 new HIV infections Statistics

occur daily around the world Over 90% of these are in developing countries 1000 are in children less than 15 years of age. Of adult infections, 40% are in women and 15% in individuals 15-25 years. As of December 1999, 733,374 Americans reported with AIDS. At least 430,441 of them have died. 11

AIDS Statistics Sub-Saharan Africa

• About 1 million new cases of AIDS per year • 24 million people with HIV infection • AIDS is responsible for a decrease in life expectancy and increase in child mortality. Child mortality rates in East Africa will double by 2010 and adult life expectancy has already declined by 2 years in that region. • Several countries in sub-Saharan Africa report infection rates of 20-25%, especially urban areas. •Botswana: 35.8% of adult population infected

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AIDS Statistics South and East Asia • In south and east Asia there are more than 200,000 new cases per year and 7.3 million people with HIV Worldwide

• Current estimates are that in 2000, 34.3 million people have

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Biological Properties

Membrane: host derived Two glycoproteins: gp160 gp41

gp120 and

gp41 is fusogen that spans the membrane There are two distinct types of human AIDS viruses14

Virus receptor HIV uses as a receptor the CD4 molecule, which is expressed on macrophages and T lymphocytes. A second co-receptor in addition to CD4 is necessary for HIV-1 to gain entry to cells 。 The second receptor is required for fusion of the virus with the cell membrane 。 CCR5 is the predominant co-receptor for macrophagetropic strains of HIV-1 ； is the co-receptor for lymphocyte-tropic strains of HIV-1 。

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HIV - Life History A retrovirus • Latency • Specific destruction of CD4+ cells

• How does the virus enter the cell?

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Disinfections and inactivation  HIV is completely inactivated by treatment for 10 minutes at room temperature with any of the following ： 50%ethanol ， 35% isopropanol ， 0.3% hydrogen peroxide 。 The virus is also inactivated by extremes in pH （ pH 1.0and 13.0 ） .HIV is readily inactivated in liquids or 10% serum by heating at 56℃ for 10 minutes 17

Pathogenesis  Sources and routes of transmission ： Patients with AIDS and asymptomatic virus-positive individuals can transmit the virus 。 HIV is transmitted --during sexual contact （ homosexual and heterosexual activity and including genital-oral sex ）； --through parenteral exposure to contaminated blood or blood products contaminated clotting factor injection ； intravenous drug abusers are infected through the use of contaminated needles --and from mother to child during the perinatal period （ in utero ， during the birth process ， or more commonly ， through breast feeding ） 18

Overview of course of HIV infection  The typical course of untreated HIV infection spans about a decade stages 10 年 include the primary infection ， dissemination of virus to lymphoid organs ， clinical latency ， elevated HIV expression ， clinical disease (AIDS) ， and death 。 In untreated cases ， death usually occurs within 2 years ， after the onset of clinical symptoms

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Following primary infection ， there is a 4- to 11day period between mucosal infection and initial viremia ； The viremia is detectable for about 8-12 weeks 。 An acute mononucleosis-like syndrome develops in many patients (50-75%) 3-6 weeks after primary infection 。 Symptoms of acute HIV infection are nonspecific and include fatigue ， rash ， headache ， nausea ， and night sweats 。

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This period of clinical latency may last for as long as 10 years 。 During this time there is a high level of ongoing viral replication 。 Eventually, the patient will develop constitutional symptoms and clinically apparent disease ， such as opportunistic infections or neoplasms (especially Kaposi's sarcoma) 。 The more serious symptoms in adults are often preceded by a prodrome that can include fatigue ， malaise ， weight loss ， fever ， shortness of breath ， chronic diarrhea ， white patches on the tongue ， and lymphadenopathy 21

Kaposi's sarcoma is a vascular tumor that appears in skin ， mucous membranes ， lymph nodes, and visceral organs 。 It was considered to be a very rare cancer 。 It is now 20 ， 000 times more common in untreated AIDS patients than in the general population.

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Treatment and Prevention    

Antiviral drugs Vaccines against HIV Control measures Health education

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Remember!

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Education led to leveling off of rate of increase in AIDS

• HAART has greatly slowed death rate •The fact that fewer people are dying per year from the infection means that the number of HIVinfected people in the population is rising! • Unless education continues to be successful and unless we can cure

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