spread of disease

• how are measles spread?

  by air - through the inhalation of droplets from coughs and sneezes
• how is HIV spread?


  direct sexual contact and exchange of bodily fluids e.g. blood
• how is TMV spread?


  contact between infected and healthy plants

  insects may act as vectors which transfer the virus between different plants
• how is rose black spot spread?

  fungal spores are spread by the wind and in water