module 4 - 12.3 transmission of communicable diseases Flashcards
how are communicable diseases transmitted?
direct and indirect transmission
what is direct transmission?
pathogen transferred directly from one individual to another
what does direct transmission involve?
- direct contact
- inoculation
- ingestion
what is direct contact?
- any contact with body fluids of another person
- direct skin-to-skin contact
- microorganisms from faeces transmitted onto the hands
what is inoculation?
- diseases though break in the skin
- from aniamal bite
- through puncture or wound through sharing needles
what is ingestion?
- taking in contaminated food or drink
- transferring pathogens to mouth from hands
what is indirect transmission?
pathogen travels from one individual to another indirectly
what does indirect transmission involve?
- fomites
- droplet infection (inhalation)
- vectors
what are fomites?
inanimate objects that can transfer pathogens
what are droplet infections?
minute droplets of saliva and mucus are expelled from your mouth as you talk, cough, or sneeze
- when healthy individuals breathe in droplets - may become infected
what are vectors?
- they transmit communicable pathogens from one host to another
- often (not always) pathogens e.g. mosquitoes, water
how can you minimise the transmission between animals and humans?
- minimising close contact
- washing hands thoroughly following any contact
what are the factors affecting transmission of communicable diseases?
- overcrowded living & working conditions
- poor nutrition
- compromised immune system
- poor disposal of waste
- climate change
- culture and infrastructure
- socioeconomic factors
how can climate change affect transmission of communicable diseases?
introduces new vectors and new diseases
(e.g. increased temp promotes spread of malaria - can survive in wider area)
how can culture and infrastructure affect the transmission of communicable diseases in animals ?
in many countries, traditional medicinal practices can increase transmission
how can socioeconomic factors affect transmission of communicable diseases?
- lack of trained health workers
- insufficient public warning when there’s an outbreak
how are diseases/ pathogens directly transmitted between plants?
direct contact of a healthy plants with any part of a diseased plant
how are diseases/pathogens indirectly transmitted between plants?
- soil contamination
- vectors: wind, water, animals, humans
how does soil contamination cause bacteria/pathogens to be indirectly transmitted between plants?
infected plants often leave pathogens or reproductive spores from protoctista or fungi in soil - infect next crop
how does the vector ‘wind’ cause bacteria/pathogens to be indirectly transmitted between plants?
bacteria, viruses and fungal spores may be carried on the wind and blown onto other plants
how does the vector ‘water’ cause bacteria/pathogens to be indirectly transmitted between plants?
spores swim in the surface film of water on leaves; raindrop splashes carry pathogens and spores
how does the vector ‘animals’ cause bacteria/pathogens to be indirectly transmitted between plants?
insects and birds carry pathogens and spores from one plant to another as they feed
- some insects inoculate pathogens directly into plant tissue
how does the vector ‘humans’ cause bacteria/pathogens to be indirectly transmitted between plants?
pathogens and spores are transmitted by hands, clothing, fomites, farming practices and by transporting plants and crops around the world
