4.1.2 transmission of pathogens Flashcards
define vector
organism that carries pathogen from one host to another
types of direct transmission between animals
- direct physical contact
- faecal-oral transmission
- droplet infection
- transmission by spores
describe direct physical contact & factors affecting the transmission
eg. touching infected individual, touching contained surfaces
factors affecting transmission:
- hygiene (eg. washing hands regularly, keeping surfaces clean, cleaning/disinfecting cuts or abrasions, disinfecting surgical equipment, use condoms during sexual intercourse)
describe faecal-oral transmission & factors affecting the transmission
eg. eating food/drink contaminated by pathogen
factors affecting transmission:
- using human sewage to fertilise crops
- treatment of waste water/drinking water
- wash all fresh food
- careful preparation/cooking of food
describe droplet infection & factors affecting the transmission
= pathogen carried by troy water droplet through air
factors affecting transmission:
- cover mouth when coughing/sneezing
- use tissue & dispose correctly
describe transmission by spores & factors affecting the transmission
= carried in air, reside on surfaces or in soil
factors affecting transmission:
- use mask
- wash skin after contact with soil
social factors which affect transmission
- overcrowding
- poor ventilation
- poor health
- poor diet
- homelessness
- living/working with people who’ve migrated from areas where disease is common
how are pathogens transmitted indirectly
by vector
how are plant pathogens spread directly
- present in soil = infect plants by entering roots
- fungi produce spores which may be carried in wind (airborne transmission)
- when leaves shed the pathogens are distributed as return to the soil
- pathogens can enter fruit/seeds = distributed with seeds (offspring infected)
how are plant pathogens spread indirectly
= insect attack
- spores/bacteria become attached to burrowing insect (eg. beetle) when it attacks infected plant
- when insect attacks another plant, pathogen transmitted
- insect acts as a vector
why are protoctists, bacteria & fungi more common in warm/moist conditions
can grow/reproduce more rapidly