viral diseases

• Measles


  spread by droplets (e.g cough)

  develop red rash and has a high temp

  can be very serious and fatal if there are complications (can lead to inflamation on brain)

  most people get vaccinated when they are young
• HIV


  spread by sexual contact or exchnage of body fluids (e.g blood)

  casuses flu-like symptons but usually for the first several years person experiences no symptons

  HIV can be controlled by antiretroiral drugs

  virus attacls immune cells

  if body immune system is badly damaged, cant cope with other infenctions. at this stage the virus is known as AIDS
• tobacco mosaic virus


  a virus that affects many species of plants (e.g tomatoes)

  casues mosaic pattern on the leaves and parts of the leaved become discoloured

  this means the plants cant carry out photosythesis good so the virus affects plant growth