module 4 - 12.3 transmission of communicable diseases

Question 1

how are communicable diseases transmitted?

Answer 1

direct and indirect transmission

Question 2

what is direct transmission?

Answer 2

pathogen transferred directly from one individual to another

Question 3

what does direct transmission involve?

Answer 3

• direct contact
• inoculation
• ingestion

Question 4

what is direct contact?

Answer 4

• any contact with body fluids of another person
• direct skin-to-skin contact
• microorganisms from faeces transmitted onto the hands

Question 5

what is inoculation?

Answer 5

• diseases though break in the skin
• from aniamal bite
• through puncture or wound through sharing needles

Question 6

what is ingestion?

Answer 6

• taking in contaminated food or drink
• transferring pathogens to mouth from hands

Question 7

what is indirect transmission?

Answer 7

pathogen travels from one individual to another indirectly

Question 8

what does indirect transmission involve?

Answer 8

• fomites
• droplet infection (inhalation)
• vectors

Question 9

what are fomites?

Answer 9

inanimate objects that can transfer pathogens

Question 10

what are droplet infections?

Answer 10

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

Question 11

what are vectors?

Answer 11

• they transmit communicable pathogens from one host to another
• often (not always) pathogens e.g. mosquitoes, water

Question 12

how can you minimise the transmission between animals and humans?

Answer 12

• minimising close contact
• washing hands thoroughly following any contact

Question 13

what are the factors affecting transmission of communicable diseases?

Answer 13

• overcrowded living & working conditions
• poor nutrition
• compromised immune system
• poor disposal of waste
• climate change
• culture and infrastructure
• socioeconomic factors

Question 14

how can climate change affect transmission of communicable diseases?

Answer 14

introduces new vectors and new diseases
(e.g. increased temp promotes spread of malaria - can survive in wider area)

Question 15

how can culture and infrastructure affect the transmission of communicable diseases in animals ?

Answer 15

in many countries, traditional medicinal practices can increase transmission

Question 16

how can socioeconomic factors affect transmission of communicable diseases?

Answer 16

• lack of trained health workers
• insufficient public warning when there’s an outbreak

Question 17

how are diseases/ pathogens directly transmitted between plants?

Answer 17

direct contact of a healthy plants with any part of a diseased plant

Question 18

how are diseases/pathogens indirectly transmitted between plants?

Answer 18

• soil contamination
• vectors: wind, water, animals, humans

Question 19

how does soil contamination cause bacteria/pathogens to be indirectly transmitted between plants?

Answer 19

infected plants often leave pathogens or reproductive spores from protoctista or fungi in soil - infect next crop

Question 20

how does the vector ‘wind’ cause bacteria/pathogens to be indirectly transmitted between plants?

Answer 20

bacteria, viruses and fungal spores may be carried on the wind and blown onto other plants

Question 21

how does the vector ‘water’ cause bacteria/pathogens to be indirectly transmitted between plants?

Answer 21

spores swim in the surface film of water on leaves; raindrop splashes carry pathogens and spores

Question 22

how does the vector ‘animals’ cause bacteria/pathogens to be indirectly transmitted between plants?

Answer 22

insects and birds carry pathogens and spores from one plant to another as they feed
- some insects inoculate pathogens directly into plant tissue

Question 23

how does the vector ‘humans’ cause bacteria/pathogens to be indirectly transmitted between plants?

Answer 23

pathogens and spores are transmitted by hands, clothing, fomites, farming practices and by transporting plants and crops around the world