Natural History and Clinical Staging of

HIV Training for Medical Officers

Day 2Session 7

Natural History of HIV and Staging of HIV 2

Session Objectives

• List the modes of HIV transmission• Discuss the pathogenesis and life

cycle of HIV • Describe the progression of HIV• Classify an HIV-infected patient

according to the WHO clinical stages

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Modes of HIV Transmission

Sharing Semen and Vaginal

Fluids

Sharing Needles

& Syringes

Through Infected Blood

During Pregnancyor Birth

Breast Feeding

© I-TECH, 2005

Needle StickInjury

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Risk of HIV Transmission with Single Unprotected Exposure

(Risk per 10,000 exposures)

Source: HIV Web Study, 2006

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How HIV Infects the BodyHIV makes contact with cells located

within the genital mucosa

Virus is carried to regional lymph nodes (1-2 Days)

Exponential viral replication

Widespread systemic dissemination to the brain, spleen, distant lymph nodes, etc. (5-

11 Days)Source: GHTM Fellowship

Programme, 2006

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© 1998 Massachusetts Medical Society. All Rights Reserved

HIV exposure atmucosal surface (sex)

Virus collected by dendritic cells, carried to lymph node

HIV replicates in CD4 cells, released into blood

Virus spreads to other organs

Day 0

Day 0-2

Day 4-11

Day 11+

Path of the Virus

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HIV Lifecycle

©I-TECH, 2005

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Life Cycle of HIV

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Stages of HIV Infection

Viral transmission (2-3 wks)

Acute retroviral syndrome (2-3 wks)

Seroconversion (2-4 wks)

Asymptomatic chronic HIV infection (Avg. 8yrs)

Symptomatic HIV infection/AIDS (Avg. 1.3 yrs)

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CD4 Count & Viral Load Over Time

Source: Fauci, et al, Immu. Mech HIV Inf, 1996

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Progression of HIV

• Acute Seroconversion• Asymptomatic HIV (Clinical latency)• Symptomatic HIV• Acquired Immune Deficiency

Syndrome (AIDS)

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Patterns of HIV Progression

• Typical progressors• Rapid progressors• Slow progressors• Long-term non-progressors

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WHO Clinical Staging

11 Case Studies

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© I-TECH, 2005

Case Study 1

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Case Study 2

© I-TECH, 2005

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Case Study 3

© I-TECH, 2005

Natural History of HIV and Staging of HIV 17

Case Study 4

© I-TECH, 2005

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Case Study 5

© I-TECH, 2005

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Case Study 6

© I-TECH, 2005

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Indian Ink Staining of Cryptococcus in CSF

Case Study 7

© I-TECH, 2005

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Case Study 8

© I-TECH, 2005

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Case Study 9

Courtesy of : GHTM, Chennai, 2006

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Case Study 10• 37 year-old HIV-positive male• Lost 9 kg in last 3 months (previously

75 kg)• Reports having a fever for the past

month• Goes to bed by late afternoon

• Treated for pulmonary TB 5 months ago

What is his WHO clinical stage?

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Case 11• 34 year-old HIV positive male • Suffers from bacterial sinusitis and

a fungal infection on his toes• Has no problem keeping up with his

usual activities and weight is stable• Treated for herpes zoster 4 years

ago

What is his WHO Clinical Stage?

Natural History of HIV and Staging of HIV 25

Key Points

• The most common mode of HIV transmission in India is sexual

• Understanding the natural history of HIV is important in predicting progress of the disease and determining when to begin ART

• Clinical staging allows clinicians to reliably predict in patients:– The risk for death and opportunistic infections– The need for disease prevention and ART