11.4 - Health Issues Related to Immunity

Acquired Immunodeficiency Syndrome (AIDS)

Cause and Mechanism

• Human immunodeficiency virus (HIV) attacks the human immune system and causes Acquired Immunodeficiency Syndrome (AIDS).
• HIV spreads in lymphocytes and destroys them progressively.
• An infected person may show no symptoms for the first few years while HIV attacks the immune system.
• Chronic diarrhoea and fungal infection may appear after 8 to 10 years.
• The weakened immune system is easily infected by diseases; it eventually becomes paralysed, and the patient may die from other infections.

Modes of HIV Transmission

• Transfer of body fluids such as blood and semen.
• Across the placenta.
• From an infected mother during pregnancy, birth or breastfeeding.
• Unprotected sexual relations with an infected person.
• Sharing contaminated needles used to inject drugs or tattoo ink.
• Transfusion of HIV-infected blood.

Other Immunity-related Conditions

• Systemic Lupus Erythematosus (SLE).
• Allergy.