Transmission of communicable diseases

• state three examples of direct transmission

  • Direct contact (contagious diseases)
  • Inoculation- through a break in a skin (eg during sex) from an animal bite or a puncture wound/sharing needles
  • Ingestion- contaminated food or drink
• State four examples of indirect transmission

  • fomites- inanimate objects like bedding sock or cosmetics
  • Droplet infections - of saliva and mucus expelled from mouth as someone talks or sneezes
  • Vectors- transmitting diseases from one host to another
  • Water can act as a vector of disease
• State five factors which increase the risk of transmission of communicable diseases

  • Overcrowded living and working conditions
  • poor nutrition
  • Compromised immune system
  • Poor disposal of waste- breeding site for vectors
  • Climate change- can introduce new vectors and new diseases
• why can plants be considered to be at a greater risk to communicable diseases than humans?

  have a less well developed immune system than humans
• what two main ways are diseases between plants transmitted?

  • direct transmission- direct contact of a plant with any part of an infected plant
  • indirect transmission- soil contamination , pathogens or spores left in soil, or vectors
• what are the four main vectors for plants that transmit disease?

  • wind- pathogens can be carried on wind
  • water- spores can swim or be carried by the wind
  • animals- insects and birds carry pathogens from one plant to another as they feed
  • Humans- transmitted by hand , clothing, fomites, transporting plants and crops around the world
• name five factors that increase the spread of communicable diseases in plants

  • planting varieties of crops susceptible to disease
  • over crowding increases likelihood of contact
  • Poor mineral nutrition reduces plant resistance
  • Damp, warm conditions increase survival and spread of pathogens and spores
  • Climate change- vectors can spread to new areas
• How can the spread of communicable diseases be prevented in plants? Name five key factors

  • Leave plenty of room between plants to minimise pathogenic spread
  • Clear fields as thoroughly as possible
  • Rotate crops- spores or bacteria will die if they have no access to the host plant
  • Follow strict hygiene practises- washing hands, washing boots
  • Control insect vectors