GOOD VIRUSES

Some infect and destroy bacterial cells [e.g. prevent bacterial infections]

Biological control [get rid of insect pests] Used as vectors in biotechnology [help to

transfer genetic material from one organism to another]

VIRUSES CAUSING DISEASES

Common cold Flu AIDS Bird flu Polio

Electron micrographs of viruses.

HIV Aeromonas virus 31 Influenza virus

Orf virusHerpes simplex virusSmallopx virus

Study only ONE disease

EITHER: HIV RABIES INFLUENZA

Effects and management

RABIES

HIV (Human Immunodeficiency Virus)HIV (Human Immunodeficiency Virus)

Is a virus that:Is very fragileDoes not live long outside of the human bodyAttacks the immune systemIs spread primarily via unprotected sex and shared needles

Is a virus that:Is very fragileDoes not live long outside of the human bodyAttacks the immune systemIs spread primarily via unprotected sex and shared needles

When the immune system becomes very affected, the illness progresses to AIDS = Acquired Immune Deficiency Syndrome

When the immune system becomes very affected, the illness progresses to AIDS = Acquired Immune Deficiency Syndrome

HIV AIDS

CAUSESCAUSES

HIV virus infects and destroys T lymphocytes [CD4 cells] in the immune system

These cells play a vital role in immunity

HIV virus infects and destroys T lymphocytes [CD4 cells] in the immune system

These cells play a vital role in immunity

HIV LIFE CYCLE

• T cells carry the CD4-antigen on their surface• Antigen = a protein molecule• HIV recognizes and combines with the CD4-antigen• It then enters the CD4 cell [host cell]• HIV uses the host cell material to make new viruses• These infect new CD4 cells• CD4 cells are destroyed• Other cells involved in immunity are not activated• Individual becomes susceptible to infections

HIV LIFE CYCLE

• T cells carry the CD4-antigen on their surface• Antigen = a protein molecule• HIV recognizes and combines with the CD4-antigen• It then enters the CD4 cell [host cell]• HIV uses the host cell material to make new viruses• These infect new CD4 cells• CD4 cells are destroyed• Other cells involved in immunity are not activated• Individual becomes susceptible to infections

HOW HIV IS SPREAD

During sexual intercourse Or contact with infected blood, semen and vaginal

secretions

Blood transfusions

Infected injecting equipment Needles, syringes or skin piercing equipment

Mother to infant transmission During pregnancy, labour, delivery or breast feeding

How Can I Prevent Myself From Getting It?

HIV and AIDS

By practicing good standard precautions in all circumstances, you can prevent catching the AIDS virus. Currently, there is no vaccine to prevent the disease, and no current drugs available to cure it. Just be careful:

HIV and AIDS

By practicing good standard precautions in all circumstances, you can prevent catching the AIDS virus. Currently, there is no vaccine to prevent the disease, and no current drugs available to cure it. Just be careful:

1. Do not have unprotected sex.

2. Know your sexual partner.

3. Do not share any type of needle.

4. Always use standard precautions for every individual you care for.

1. Do not have unprotected sex.

2. Know your sexual partner.

3. Do not share any type of needle.

4. Always use standard precautions for every individual you care for.

HIV-1 StructureHIV-1 Structure

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EFFECT OF HIV ON THE BODYEFFECT OF HIV ON THE BODY

IMMUNE SYSTEM WEAKENS Lack of energy Rapid weight loss Frequent fevers and sweats Fungal infections occur – oral or vaginal Shingles Skin rashes Diarrhoea Blemishes on the tongue or mouth or throat

IMMUNE SYSTEM WEAKENS Lack of energy Rapid weight loss Frequent fevers and sweats Fungal infections occur – oral or vaginal Shingles Skin rashes Diarrhoea Blemishes on the tongue or mouth or throat

OTHER EFFECTS OF AIDSOTHER EFFECTS OF AIDS

Sufferers experience feelings of ostracism, alientation and loneliness

Negative effects on the economy Family network breaks down High financial costs to individuals

Loss of earning Travel expenses Burial expenses

Financial costs to government Purchase of drugs Maintenance of health facilities Loss of income due to lost days work

Sufferers experience feelings of ostracism, alientation and loneliness

Negative effects on the economy Family network breaks down High financial costs to individuals

Loss of earning Travel expenses Burial expenses

Financial costs to government Purchase of drugs Maintenance of health facilities Loss of income due to lost days work

MODERN TREATMENTMODERN TREATMENT

Anti-retroviral treatment Drugs which stop viral replication

Treatment of opportunistic infections Drugs are used to treat these infections

Boosting the immune system Slow down the effects of HIV infection Good diet, etc

Anti-retroviral treatment Drugs which stop viral replication

Treatment of opportunistic infections Drugs are used to treat these infections

Boosting the immune system Slow down the effects of HIV infection Good diet, etc

THE END