Human immunodeficiency virus an overview
Download
1 / 71

- PowerPoint PPT Presentation


  • 153 Views
  • Updated On :

Human Immunodeficiency Virus: An Overview. Elizabeth W. Delamater, Ph.D. Manager, Microbiological Sciences Division Laboratory Services Section Texas Department of State Health Services. HIV-1. HTLV-I. HIV-2. HTLV-II. (SIV). (STLV-I). Common Ancestor. Transforming Viruses

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about '' - steve


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Human immunodeficiency virus an overview

Human Immunodeficiency Virus: An Overview

Elizabeth W. Delamater, Ph.D.

Manager, Microbiological Sciences Division

Laboratory Services Section

Texas Department of State Health Services


HIV-1

HTLV-I

HIV-2

HTLV-II

(SIV)

(STLV-I)

Common Ancestor

Transforming Viruses

Cell Proliferation

Cytopathic Viruses

Cell Death


Human retroviruses nomenclature
Human Retroviruses - Nomenclature

  • Human Immunodeficiency Viruses

    • HIV-1 (1983)

      • HIV, HTLV III, LAV, ARV

        • AIDS and related conditions

    • HIV-2 (1986)

      • LAV-2, HTLV IV

        • AIDS (primarily in West Africa)


Human retrovirus characteristics
Human Retrovirus – Characteristics

  • RNA Tumor (transforming) and immunodeficiency (cytopathic) viruses

  • Reverse Transcriptase

  • Integration of the viral genome into the host DNA as a provirus

  • Primarily infect T-lymphocytes and some neural cells

  • Exogenous (transmisssible, infectious agents)

  • Latency (long incubation period)


Brief history of retroviruses
Brief History of Retroviruses

  • Transmissible agents capable of causing leukemias and solid-tissue tumors were discovered

    • 1970 – Reverse transcriptase was discovered

    • 1980 – HTLV-I and HTLV-II were isolated

    • 1981 – First AIDS case was discovered

    • 1983 – HIV-1 was isolated

    • 1985 – EIA test for anti-HIV-1 antibodies was licensed by the FDA


Where did hiv come from
Where did HIV come from?

  • Estimated origin around 1930.

  • Estimated origin in Africa.

  • Thought to come from SIV in primates (blood exposure)

  • Change in travel and social norms caused the world wide epidemic.


Hiv subtypes
HIV Subtypes

  • HIV isolates are classified into three different groups

    • Major group (M)

    • Outlier group (O)

    • Non-M / non-O (N)

  • Groups N and O restricted to West Africa

  • Based on the analysis of the envelope gene, there are at least nine pure subtypes or clades A-D, F-H, J and K


Hiv transmission
HIV Transmission

Requires:

1) Infected body fluid.

2) Entry into the body.

Blood, Semen, Vaginal Secretions & Breast Milk

Mucous Membrane--Anal, Oral or Vaginal Sex

Blood to Blood--Needle or Broken Skin

Perinatal- In utero, During birth, Breastfeeding


Routes of transmission of hiv

Sexual

Exposure to

blood

Perinatal

Homosexual between men

Heterosexual from men to women and women to men

Drug user needle sharing

Transfusion of blood, plasma

Occupational needlestick injury and other blood exposures

During pregnancy, intrapartum and postpartum (via breastfeeding)

Routes of Transmission of HIV


Perinatal transmission
Perinatal transmission

  • Greatly reduced due to use of antiretroviral therapy during pregnancy

    • decrease from 24 to 8% vertical transmission with AZT

  • Trials using high doses of new antiretrovirals during labor and to newborn--success of Nevirapine

  • Women with higher viral loads more likely to transmit


Factors Affecting Transmission

STD Co-infection More likely to become infected More likely to transmit infection

Viral Load Stage of infection Treatment


Disease progression
Disease Progression

  • Infection

  • Primary Infection/Antibody Development

  • Asymptomatic Period (10-12 yrs average)

  • AIDS (Opportunistic infections, CD4 200 or below)


AIDS

HIV infected + immune system breakdown

(CD4 count < 200 or AIDS Defining illness)

AIDS Defining Illnesses

Pnuemocystis pnuemonia

Toxoplasmosis

Kaposi’s sarcoma

Mycobacterium avium complex

Invasive cervical cancer

etc...


Antiretroviral Treatment

Triple Drug Cocktail--Attack the virus at different points in the replication process

  • Difficult Drug Regimens

  • Importance of Adherence

  • Side Effects

  • Expensive


Other Treatment

Prophylaxis for Opportunistic Infections

Treatment of Opportunistic Infections

Vaccines (future)

Immune Therapy

Alternative Treatment


Difficulties in treatment
Difficulties in Treatment

  • Access to Care

  • Family Care Burdens

  • Language Barriers

  • Fragmentation of Care

  • Fears / Myths About Medical Care


Post exposure prophylaxis
Post Exposure Prophylaxis

  • Treatment with antiretroviral drugs after an exposure to HIV.

  • Must be started within 72 hours (sooner the better) and continued for a month.

  • PEP showed a 80% reduction in HIV infections for occupational exposures.

  • Concerns for drug and sexual exposures


1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

Estimated Number of AIDS Cases, Deaths, and

Persons Living with AIDS,1985-2004, United States

450

90

AIDS

1993 definition

implementation

400

Deaths

80

Prevalence

350

70

300

60

No. of cases and deaths (in thousands)

250

50

Prevalence (in thousands)

200

40

150

30

20

100

10

50

0

0

Year of diagnosis or death

Note. Data adjusted for reporting delays.


Awareness of HIV Status among

Persons with HIV, United States

Number HIV infected 1,039,000 – 1,185,000

Number unaware of

their HIV infection 252,000 - 312,000 (24%-27%)

Estimated new infections 40,000

annually

Glynn M, Rhodes P. 2005 HIV Prevention Conference


Awareness of serostatus among people with hiv and estimates of transmission
Awareness of Serostatus Among People with HIV and Estimates of Transmission

~25% Unaware of Infection

Accounting for:

~54% of New Infections

Marks, et al

AIDS 2006;20:1447-50

~75% Aware of Infection

~46% of New Infections

People Living with HIV/AIDS: 1,039,000-1,185,000

New Sexual Infections Each Year: ~32,000


HIV/AIDS Diagnoses among Adults and Adolescents, by Transmission Category — 33 States, 2001–2004

MSM/IDU 5%

Other 1%

Other 3%

Heterosexual

17%

IDU

21%

MSM

61%

IDU

16%

Heterosexual

76%

Females

(n ≈ 45,000)

Males

(n ≈ 112,000)

MMWR, Nov 18, 2005


USA

  • Numbers of AIDS deaths are falling

  • Number of AIDS diagnosis are falling

  • Rates of HIV infection have NOT changed

  • Trends

    • Younger People (25% under age 25)

    • Low Socioeconomic Status

    • IDU

    • Disease of the Marginalized


Knowing you are infected
Knowing You Are Infected:

  • Primary Infection

    • 2-6 wks average

    • 75 -90% have symptoms

  • Only way to know for sure: HIV Antibody Test

    “Window Period”: time to develop antibodies

    • 3-6 weeks 85%

    • 3 months >99%


  • Testing technology

    Technologies

    More accurate serum EIA

    Oral fluids test

    Home test system

    Rapid test

    Urine test

    Strategies

    Phone results

    Augmented counseling

    Outreach

    Bars, coffee shops, bath houses

    Syringe exchanges

    Street (vans)

    Testing Technology


    Tdh hiv 1 testing algorithm
    TDH HIV-1 Testing Algorithm

    Patient Specimen – EIA Screen

    Nonreactive

    Reactive

    Repeat screen 2X

    No further

    Testing

    Report as

    Nonreactive

    Reactive

    Nonreactive

    Nonreactive 2X

    Reactive 2X

    No further

    Testing

    Report as

    Nonreactive

    Western Blot Confirmation

    Reactive

    Indeterminate

    Nonreactive

    Retest

    8 weeks

    Report Reactive

    Report Nonreactive


    Hiv screening enzyme immunoassay eia or elisa

    HIV ScreeningEnzyme ImmunoassayEIA or ELISA


    Eia or elisa advantages
    EIA or ELISAAdvantages

    • Simple

    • Sensitive

    • Rapid

    • Can be Automated

    • Suitable for High Volume Testing


    Eia or elisa limitations
    EIA or ELISALimitations

    • Potential for False Positives

    • Initial High Reactives must be Repeated



    Plate with Antigen coated wells

    Add patient serum sample containing anti-HIV-1 antibodies

    Wash, add enzyme conjugated anti-human antibodies


    Wash, add appropriate substrate for the conjugated enzyme

    Enzyme acts on substrate, causing a color change


    Types of specimens for testing1
    Types of Specimens for Testing

    Serum or Plasma

    Dried Blood Spots


    Types of specimens for testing2
    Types of Specimens for Testing

    Serum or Plasma

    Dried Blood Spots

    Oral Fluid


    Types of specimens for testing3
    Types of Specimens for Testing

    Serum or Plasma

    Dried Blood Spots

    Oral Fluid

    Urine


    Hiv confirmation

    HIV Confirmation

    Western Blot

    Immunofluorescent Assay

    Laboratory Only


    gp160

    gp120

    p66

    gp41

    p24

    p17


    What about hiv 2

    What about HIV-2?

    Not common in the United States

    Only about 72 cases confirmed as of 2000


    gp160

    gp120

    gp41

    HIV-2 confirmed by the CDC



    Public health need for rapid hiv tests
    Public Health Need for Rapid HIV Tests

    • High rates of non-return for test results

      • In 2000, 31% did not return for results of HIV-positive conventional tests at publicly funded sites

    • Need for immediate information or referral for treatment choices

      • Perinatal settings

      • Post-exposure treatment settings

    • Screening in high-volume, high-prevalence settings


    Multispot HIV-1/HIV-2

    Uni-Gold Recombigen

    Reveal G2

    OraQuick Advance


    Four fda approved rapid hiv tests
    Four FDA-approved Rapid HIV Tests

    Sensitivity

    (95% C.I.)

    Specificity

    (95% C.I.)

    OraQuick Advance

    - whole blood

    - oral fluid

    - plasma

    99.6 (98.5 - 99.9)

    99.3(98.4 - 99.7)

    99.6 (98.5 - 99.9)

    100(99.7-100)

    99.8(99.6 – 99.9)

    99.9(99.6 – 99.9)

    Uni-Gold Recombigen

    - whole blood

    - serum/plasma

    100(99.5 – 100)

    100 (99.5 – 100)

    99.7(99.0 – 100)

    99.8 (99.3 – 100)


    Four fda approved rapid hiv tests1
    Four FDA-approved Rapid HIV Tests

    Sensitivity

    (95% C.I.)

    Specificity

    (95% C.I.)

    Reveal G2

    serum

    plasma

    99.8(99.2 – 100)

    99.8(99.0 – 100)

    99.1 (98.8 – 99.4)

    98.6 (98.4 – 98.8)

    Multispot

    serum/plasma

    HIV-2

    100 (99.9 – 100)

    100 (99.7 – 100)

    99.9 (99.8 – 100)


    Revised recommendations adults and adolescents i
    Revised RecommendationsAdults and Adolescents - I

    • Routine, voluntary HIV screening for all persons 13-64 in health care settings, not based on risk

    • Repeat HIV screening of persons with known risk at least annually

    • Opt-out HIV screening with the opportunity to ask questions and the option to decline

    • Include HIV consent with general consent for care; separate signed informed consent not recommended

    • Prevention counseling in conjunctions with HIV screening in health care settings is not required


    Opt out screening
    Opt-Out Screening

    Prenatal HIV testing for pregnant women:

    • RCT of 4 counseling models with opt-in consent:

      • 35% accepted testing

      • Some women felt accepting an HIV test indicated high risk behavior

    • Testing offered as routine, opportunity to decline

      • 88% accepted testing

      • Significantly less anxious about testing

    Simpson W, et al, BMJ June,1999


    Routine opt out hiv testing texas std clinics 1996 97
    Routine Opt-Out HIV TestingTexas STD Clinics, 1996-97

    Opt-In Opt-Out

    N (%) N (%) % change

    STD Visits 31,558 34,533 +9 Eligible Clients 19,184 (61) 23,686 (69) +23

    Pre-test counsel 15,038 (78) 11,466 (48) -24

    Tested 14,927 (78) 23,020 (97) +54

    Post-test counsel 6,014 (40) 4,406 (19) -27

    HIV-positive 168 (1.1) 268 (1.2) +59

    Texas Department of State Health Services, 2005


    Revised recommendations adults and adolescents ii
    Revised RecommendationsAdults and Adolescents - II

    • Intended for all health care settings, including inpatient services, EDs, urgent care clinics, STD clinics, TB clinics, public health clinics, community clinics, substance abuse treatment centers, correctional health facilities, primary care settings

    • Communicate test results in same manner as other diagnostic/screening tests

    • Provide clinical HIV care or establish reliable referral to qualified providers


    Revised recommendations adults and adolescents iii
    Revised RecommendationsAdults and Adolescents - III

    • Low prevalence settings:

      • Initiate screening

      • If yield from screening is less than 1 per 1000, continued screening is not warranted

    • Steps should be considered to resolve conflicts between the recommendations and state or local regulations


    Revised recommendations pregnant women i
    Revised RecommendationsPregnant Women - I

    • Universal opt-out HIV screening

      • Include HIV in routine panel of prenatal screening tests

      • Consent for prenatal care includes HIV testing

      • Notification and option to decline

    • Second test in 3rd trimester for pregnant women:

      • Known to be at risk for HIV

      • In jurisdictions with elevated HIV incidence

      • In high HIV prevalence health care facilities


    Revised recommendations pregnant women ii
    Revised RecommendationsPregnant Women - II

    • Opt-out rapid testing with option to decline for women with undocumented HIV status in L&D

      • Initiate ARV prophylaxis on basis of rapid test result

    • Rapid testing of newborn recommended if mother’s status unknown at delivery

      • Initiate ARV prophylaxis within 12 hours of birth on basis of rapid test result


    Summary
    Summary

    • There is an urgent need to increase the proportion of persons who are aware of their HIV-infection status

    • Expanded, routine, voluntary, opt-out screening in health care settings is needed

    • Such screening is cost-effective

    • Recommendations Revised: September 2006

    • Several jurisdictions have already begun


    Key messages
    Key Messages

    • The large majority of people with HIV continue to be men who have sex with men. People of color are disproportionately represented among new infections

    • The basic modes of transmission and prevention of HIV have not changed in 20 years

    • The AIDS epidemic is not over, but there is more hope than ever for those that are infected


    ad