disease transmission

direct transmission for animals

• direct contact

• inoculation

• ingestion

direct transmission

• passed via kissing or bodily fluid contact

• diseases include meningitis and stds

• skin to skin- athletes foot

• microorganisms from faeces pass via hands

inocluation

• via break in skin

• animal bites eg rabies

• puncture wound and sharing needles hiv/aids

ingestion

• taking contaminated food and drink

• transferring pathogens to the mouth from hands eg diarrhoea

indirect transmission in animals

• fomites

• droplet infection

• vectors

fomites

• inanimate objects eg bedding can transfer pathogens eg athletes foot

droplet infection (inhalation)

• minute droplets of saliva and mucus are expelled from mouth as you talk, cough or sneeze

  • if droplets contain pathogens, healthy individuals will breathe them in

  • eg influenza and tuberculosis

vectors

• transmits communicable pathogens from one host to another

  • often but not always animals eg mosquitos and malaria

  • rat fleas transmit plague

  • water-diarrhoeal diseases

factors affecting the transmission of communicable diseases in animals

• overcrowded living and working conditions

• compromised immune system eg aids

• climate change

direct transmission in plants

• direct contact

direct contact in plants

• contact of healthy plant and diseased plant

• ring rot, tobacco mosaic

indirect transmission in plants

• soil contamination

• vector

soil contamination

• infected plants leave pathogens (bacteria and viruses) or reproductive spores from Protoctista or fungi in soil

  • these infect next crop

  • eg black sigatoka spores

  • ring rot

vector examples for plants

• wind

• water

• animals

• humans

vectors- wind

• wind - bacteria, viruses and fungal spores carried in wind eg black sigatoka

vectors- water

• spores swim in the surface film of water on leaves eg potato blight

vector- animals

• insects and birds carry pathogens and spores eg aphids

vector- humans

• pathogens and spores are transmitted by hands eg clothing

factors affecting transmission of communicable diseases in plants

• planting varieties of crops are susceptible to disease

• overcrowding increases the likelihood of contact

• climate change -increased rainfall and wind promote