Human Immunodeficiency Virus. Acquired Immune Deficiency Syndrome AIDS

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2 Human Immunodeficiency Virus Acquired Immune Deficiency Syndrome AIDS

3 Sudden outbreak in USA of opportunistic infections and cancers in young men in 1981 Pneumocystis carinii pneumonia (PCP), Kaposi s sarcoma, and non-hodkins lymphoma HIV isolated in Luc Montagnier (Pasteur Institute, Paris) and Robert Gallo ( 1986) (NIH, Bethesda, USA) 3

4 HIV diagnostic tests developed in 1985 First antiretroviral drug, zidovudine, developed in 1986 Exploding pandemic Has infected more than 50 million people around the world Has killed over 22 million people

7 36.7 million [30.8 million 42.9 million] people globally were living with HIV in million [1.6 million 2.1 million] people became newly infected with HIV in million [ million] people died from AIDS-related illnesses in million [65.2 million 88.0 million] people have become infected with HIV since the start of the epidemic million [28.9 million 41.5 million] people have died from AIDS-related illnesses since the start of the epidemic.

8 In 2016, there were 36.7 million [30.8 million 42.9 million] people living with HIV million [28.8 million 40.2 million] adults 17.8 million [15.4 million 20.3 million] women (15+ years) 2.1 million [1.7 million 2.6 million] children (<15 years)

10 Family : Retroviridae Genus: Lentivirinae: Types: HIV-1 HIV-2

11 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.

14 Virion: Spherical, nm in diameter, cylindric core Genome: Single-stranded RNA, linear, positive-sense, 9 10 kb, diploid; genome more complex than that of oncogenic retroviruses, contains up to six additional replication genes

15 Proteins: Envelope glycoprotein undergoes antigenic variation; reverse transcriptase enzyme contained inside virions; protease required for production of infectious virus

16 Envelope: Present Replication: Reverse transcriptase makes DNA copy from genomic RNA; provirus DNA is template for viral RNA. Genetic variability is common. Maturation: Particles bud from plasma membrane Outstanding characteristics: Members are nononcogenic and may be cytocidal Infect cells of the immune system

19 Variation among individuals Variation within the individual Variation between different geographical areas

20 Three main structural genes: Group Specific Antigen (Gag) Envelope (Env) Polymerase (Pol)

protruding cap glycoprotein (gp) 120, and a stem gp14.

21 The outer shell of the virus is known as the Viral enevlope. Embedded in the viral envelope is a complex protein known as env which consists of an outer protruding cap glycoprotein (gp) 120, and a stem gp14. Within the viral envelope is an HIV protein called p17(matrix), and within this is the viral core or capsid, which is made of another viral protein p24(core antigen).

22 First step, HIV attaches to susceptible host cell. Site of attachment is the CD4 antigen found on a variety of cells helper T cells macrophages monocytes B cells microglial brain cells intestinal cells T cells infected later on.

23 In early phase HIV infection, initial viruses are M-tropic. Their envelope glycoprotein gp120 is able to bind to CD4 molecules and chemokine receptors called CCR5 found on macrophages

24 In late phase HIV infection, most of the viruses are T- tropic, having gp120 capable of binding to CD4 and CXCR4 found on T4- lymphocytes.

27 HIV-1 and HIV-2 Transmitted through the same routes Associated with similar opportunistic infections

28 Differences between HIV-1 and HIV-2 HIV-1 is more common worldwide. HIV-2 is found primarily in West Africa, Mozambique and Angola. HIV-2 is less easily transmitted. HIV-2 develops more slowly.

29 Sexual transmission, presence of STD increases likelihood of transmission. Exposure to infected blood or blood products. Use of contaminated clotting factors by hemophiliacs. Sharing contaminated needles (IV drug users). Transplantation of infected tissues or organs. Mother to fetus, perinatal transmission variable, dependent on viral load and mother s CD 4 count.

31 Tears Saliva Sweat Urine of an HIV infected person 31

32 When a person gets infected it may take 6 weeks or up to 3 months before antibodies to HIV are detected in the blood The HIV test looks for antibodies. When these antibodies are detected the person is diagnosed HIV positive A person can be positive and the test shows negative because the test was done during the window period 3/28/2019 Copyright - National HIV/STI Programme 32

33 Mononucleosis-like, cold or flu-like symptoms may occur 6 to 12 weeks after infection. lymphadenopathy fever rash headache Fatigue diarrhea sore throat neurologic manifestations. no symptoms may be present

34 Symptoms are relatively nonspecific. HIV antibody test often negative but becomes positive within 3 to 6 months, this process is known as seroconversion. Large amount of HIV in the peripheral blood. Primary HIV can be diagnosed using viral load titer assay or other tests. Primary HIV syndrome resolves itself and HIV infected person remains asymptomatic for a prolonged period of time, often years.

35 HIV continues to reproduce, CD4 count gradually declines from its normal value of Once CD4 count drops below 500, HIV infected person at risk for opportunistic infections. The following diseases are predictive of the progression to AIDS: persistent herpes-zoster infection (shingles) oral candidiasis (thrush) oral hairy leukoplakia Kaposi s sarcoma (KS)

37 Being that HIV reduces immunologic activity, the intraoral environment is a prime target for chronic secondary infections and inflammatory processes, including OHL, which is due to the Epstein-Barr virus under immunosuppressed conditions

38 Kaposi s sarcoma (shown) is a rare cancer of the blood vessels that is associated with HIV. It manifests as bluishred oval-shaped patches that may eventually become thickened. Lesions may appear singly or in clusters.

39 Respiratory system Pneumocystis Carinii Pneumonia (PCP) Tuberculosis (TB) Kaposi's Sarcoma (KS) Gastro-intestinal system Cryptosporidiosis Candida Cytomegolavirus (CMV) Isosporiasis Kaposi's Sarcoma

40 Central/peripheral Nervous system Cytomegolavirus Toxoplasmosis Cryptococcosis Non Hodgkin's lymphoma Varicella Zoster Herpes simplex Skin Herpes simple Kaposi's sarcoma Varicella Zoster

41 Failure to thrive Persistent oral candidiasis Hepatosplenomegaly Lymphadenopathy Recurrent diarrhea Recurrent bacterial infections Abnormal neurologic findings.

42 Methods utilized to detect: Antibody Antigen Viral nucleic acid Virus in culture

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Virology Introduction. Definitions. Introduction. Structure of virus. Virus transmission. Classification of virus. DNA Virus. RNA Virus. Treatment.

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