Human Immunodeficiency Virus (HIV) and Acquired Immunodeficiency Syndrome (AIDS)

 Human Immunodeficiency Virus (HIV) and Acquired Immunodeficiency Syndrome (AIDS)

1.1 Definitions

• HIV (Human Immunodeficiency Virus): A virus that attacks the immune system, specifically CD4 cells (T-cells), leading to AIDS. There are two types: HIV-1 (more severe) and HIV-2.

• AIDS (Acquired Immunodeficiency Syndrome): A condition where the immune system is severely weakened by HIV, making the body vulnerable to opportunistic infections and certain cancers.

---

1.2 Historical Development

• HIV/AIDS was first identified as a new disease in 1981 and has since become a global epidemic.

• The first case of AIDS in Zambia was diagnosed in 1984.

---

Epidemiology

Distribution of HIV Prevalence

• Urban vs. Rural: HIV prevalence is higher in urban areas (23%) compared to rural areas (11%).

• Gender Disparity: Women are 1.4 times more likely to be infected than men.

• National Prevalence: Zambia’s overall HIV prevalence rate is 14.3% (ZDHS, 2008).

HIV Prevalence by Age and Gender (2002)

• Men: 13%

• Women: 18%

• Urban Areas: 25%

• Rural Areas: 13%

• Overall: 16%

---

Mode of Transmission

1. Sexual Transmission:

   • Heterosexual and homosexual intercourse.

   • Risk increases with multiple partners, unprotected sex, and the presence of other sexually transmitted infections (STIs), especially ulcerative STIs.

2. Parenteral Transmission:

   • Blood transfusions, contaminated needles, and surgical instruments.

   • High-risk groups include healthcare workers and intravenous drug users.

3. Perinatal Transmission (Mother-to-Child Transmission, MTCT):

   • During pregnancy (transplacental), childbirth (contact with genital fluids), and breastfeeding.

---

Dynamics of HIV Infection

• Life Cycle of HIV: The virus replicates within 1.2 days.

• Virion Lifespan: The virus exists in plasma for 10–20 minutes before infecting new cells.

---

Factors Contributing to the Spread of HIV in Zambia

• High prevalence of STIs.

• Multiple sexual partners and unprotected sex.

• Poverty and poor health infrastructure.

• Low social and economic status of women.

• Urbanization and mobility.

• Early sexual activity.

• Cultural beliefs and practices.

• Unscreened blood transfusions.

• Reuse of unsterilized injection equipment.

• Religious doctrines discouraging condom use.

• Lack of open discussions on sexual health.

• Poor nutrition and healthcare facilities.

• Occupational risks (e.g., truck drivers, military personnel, healthcare workers).

---

HIV is NOT Transmitted Through:

• Casual contact (e.g., shaking hands, sharing utensils, coughing).

• Saliva, food, or water.

• Sharing toilets or towels.

---

Pathophysiology and Clinical Manifestations

• HIV attacks CD4 cells (T-lymphocytes), weakening the immune system.

• The virus reprograms CD4 cells to produce more HIV instead of fighting pathogens.

• This leads to immunodeficiency, making the body susceptible to opportunistic infections and cancers.

---

Stages of HIV Progression

1. Window Period:

   • Time from infection to when HIV tests become positive (6–12 weeks).

   • Symptoms: Flu-like illness (fever, fatigue, night sweats, swollen glands).

2. Seroconversion:

   • Development of detectable HIV antibodies (2–4 weeks post-exposure).

   • Highly infectious due to rapid viral replication.

3. Asymptomatic Stage:

   • No symptoms, but HIV is active in lymph nodes, spleen, and tonsils.

   • Duration varies based on health habits, diet, and immune status.

4. Symptomatic Stage:

   • Immune system deterioration leads to symptoms:

     • Persistent generalized lymphadenopathy (PGL).

     • Fatigue, fever, night sweats.

     • Weight loss (>10% of body weight).

     • Chronic diarrhea (>1 month).

5. Full-Blown AIDS:

   • Severe immune suppression.

   • Multiple opportunistic infections and cancers.

---

Diagnosis of HIV

• Clinical Suspicion: Supported by laboratory testing.

• HIV Tests:

  • Antibody Detection: ELISA, Western Blot.

  • Viral Detection: PCR, p24 antigen test (useful for early diagnosis and MTCT).

HIV Diagnosis in Infants

• Maternal antibodies can persist for 12–18 months, complicating diagnosis.

• Viral tests (e.g., PCR) are used to confirm infection in infants.

---

WHO Clinical Staging for Adults

Stage	Symptoms	CD4 Count
1	Asymptomatic or persistent generalized lymphadenopathy.	>500
2	Weight loss (<10%), recurrent infections, oral ulcers, herpes zoster.	350–500
3	Weight loss (>10%), chronic diarrhea, fever, severe bacterial infections.	250–350
4	Wasting syndrome, opportunistic infections (e.g., TB, cryptococcal meningitis).	<200

---

WHO Clinical Staging for Children

Stage	Symptoms
1	Asymptomatic or generalized lymphadenopathy.
2	Chronic diarrhea, failure to thrive, recurrent infections.
3	Severe failure to thrive, AIDS-defining opportunistic infections.
4	Progressive encephalopathy, malignancies, recurrent sepsis.

---

Opportunistic Infections (OIs)

Common OIs

• Tuberculosis (TB): Pulmonary infiltrates, lymphadenopathy, meningitis.

• Bacterial Pneumonia: Pulmonary infiltrates.

• Candidiasis: Oral or esophageal thrush.

• Herpes Simplex Virus (HSV): Chronic mucocutaneous ulcers.

Less Common OIs

• Cryptosporidiosis: Chronic diarrhea.

• Cryptococcosis: Meningitis, pulmonary infiltrates.

• Pneumocystis Pneumonia (PCP): Pulmonary infiltrates.

• Cytomegalovirus (CMV): Retinitis, GI ulceration.

Rare OIs

• Kaposi’s Sarcoma (KS): Purple skin lesions, lymph node involvement.

• Progressive Multifocal Leukoencephalopathy (PML): Neurological symptoms.

---

Kaposi’s Sarcoma (KS)

• Presentation: Purple, non-painful skin lesions; may involve lymph nodes, lungs, or GI tract.

• Treatment:

  • Stage 1: Vincristine (2mg IV every 3 weeks for 3–6 doses).

  • Stage 2/3: Vincristine + Actinomycin D (2mg IV every 3 weeks for 3–6 doses).

---

Herpes Zoster

• Cause: Reactivation of the varicella-zoster virus (chickenpox).

• Symptoms: Painful, itchy rash following nerve pathways.

• Treatment: Antiviral medications (e.g., acyclovir).