1. 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]

2. 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

4. Study only ONE disease  EITHER:  HIV  RABIES  INFLUENZA  Effects and management RABIES

5. HIV (Human Immunodeficiency Virus) Is a virus that:  Is very fragile  Does not live long outside of the human body  Attacks the immune system  Is spread primarily via unprotected sex and shared needles Is a virus that:  Is very fragile  Does not live long outside of the human body  Attacks the immune system  Is spread primarily via unprotected sex and shared needles

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

7. CAUSES  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

8. 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

9. 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

10. 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.

11. HIV-1 Structure 11

12. EFFECT 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

13. OTHER 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

14. MODERN 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

15. THE END