Immunity, AIDS and Substance Abuse — Part 2: AIDS, alcohol, smoking and drugs: visual lesson, ISC Class 12 Biology

Lesson

AIDS and substance abuse

Part 2 — a virus that destroys the immune system, and substances that damage body and mind.

In this lesson you will

Describe HIV, its transmission, replication in the host, diagnosis by ELISA and prevention
Give the sources and effects of opioids, cannabinoids, cocaine and barbiturates, and of alcohol and smoking
Explain reasons for addiction and measures for its prevention and control

Concept

AIDS and HIV

AIDS (Acquired Immuno Deficiency Syndrome), first reported in 1981, is caused by HIV (Human Immunodeficiency Virus), a retrovirus with an RNA genome. There is a long incubation period, from a few months to many years (usually 5–10).

Table of ways HIV is and is not spread
Spread by	Not spread by
Sexual contact with an infected person	Touch, hugging, sharing food
Transfusion of contaminated blood	Mosquito bites
Sharing infected needles and syringes	Coughs and sneezes
Infected mother to child through the placenta	Swimming pools

Diagram

Replication of HIV in the host

HIV enters macrophages and helper T-lymphocytes (T_H cells). Reverse transcriptase copies its RNA into viral DNA, which is integrated into the host DNA. The infected cell then makes new viruses. Macrophages keep producing virus (an HIV factory), while helper T-cells are destroyed.

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