transmission of pathogen

• Pathogen’s Life cycle

  • travel from one host to another (transmission)
  • entering the host’s tissue
  • reproducing
  • leaving the host’s tissue
• Direct transmission - passing a pathogen from host to new host, with no intermediary
• Factors affecting direct transmission

  A)

  B)

  C)

  D)

  E)

  F)

  
• other factors that affect transmission include social factors such as :

  overcrowding - many people living and sleeping together in one house

  poor ventilation

  poor health - particularly if a person has HIV/AIDS, as they are more likely to contract other disease

  poor diet

  homelessness

  living or working with people who have migrated from areas where a disease is more common
• Direct transmission - passing a pathogen from host to new host, with no intermediary
• Indirect transmission - passing a pathogen from host to new host, via a vector
• tuberculosis is not transmitted easily; often takes living in close proximity to people with it for a long time before it is transmitted
• Transmission of plant pathogens

  plant pathogens can be also spread by direct and indirect means

  Many pathogens are present in soil and will infect plants by entering roots - especially if these have been damaged as a result of replanting,burrowing animals or movement caused by a storm.

  Many fungi produce spores as a means of sexual or asexual reproduction. These spres may be carried in the wind - airborne transmission