Module 4

• What is ring rot

  A bacterial disease caused by Gram positive bacteria which damages leaves tubers and fruits

  there is no cure
• What is tobacco mosaic virus

  • Viral disease
  • affects tobacco plants tomato’s and cucumbers
  • damages leaves flowers and fruit
  • stunts growth and reduces yield
  • no cure however there are resistant crop strains
• What is potato blight

  • Cause by a protoctist oomycete
  • hyphae penetrate host cells destroying leaves tubers and fruit
  • no cure but resistant strains
  • chemical treatments cans reduce infection risk
• what is black Sigatoka

  • Affects bananas
  • fungal disease
  • hyphae penetrate and digest the cells turning leaves black
  • there are resistant strains
  • fungicide can control the spread
  • no cure
• Tuberculosis

  • Bacterial disease
  • caused by mycobacterium tuberculosis and M.bovis
  • destroys lung tissue and suppresses the immune system so the body is more susceptible to other diseases
  • Curable with antibiotics
  • preventable by improving living standards and vaccination
• Bacterial meningitis

  • Bacterial disease
  • affects the meninges of the brain which can spread to the rest of the body causing septicaemia and rapid death
  • affects children and teenagers mainly
  • symptoms are blotchy red or purple rash that does not disappear when a glass is pressed against it
  • antibiotics can cure is administered early
  • vaccines can protect
• HIV/AIDS

  Caused by HIV (human immunodeficiency virus), which targets T helper cells in the immune system of the body
• HIV/AIDS

  Gradually destroys the immune system so affected people are open to other infections, such as TB and pneumonia, as well as some types of cancer
• HIV

  A retrovirus with RNA as its genetic material, containing the enzyme reverse transcriptase, which transcribes the RNA to a single strand of DNA to produce a single strand of DNA in the host cell
• Ways HIV is passed from one person to another

  • Unprotected sex
  • Shared needles
  • Contaminated blood products
  • From mothers to their babies during pregnancy, birth or breast feeding
• There is as yet no vaccine and no cure for HIV/AIDS, but anti-retroviral drugs slow the progress of the disease to give many years of healthy life
• Female genital mutilation (FGM)

  Increases the infection rate if the same equipment is used multiple times, and also makes women more vulnerable to infection during intercourse
• Influenza (flu)

  • Viral infection
  • destroys ciliated epithelial cells leaving the airways open to a secondary infection
  • most deaths come from the opportunistic infections such as pneumonia
  • 3 strains A B and C