Transmission of Communicable Pathogens

Question 1

Definition of communicable disease

Answer 1

disease that can be spread between organisms

Question 2

What is direct transmission?

Answer 2

when a disease is transmitted directly from one organism to another eg. droplet infection, touch, sexual intercourse

Question 3

What are 3 elements of living conditions that could cause pathogen transmission?

Answer 3

-overcrowding
-climate
-social factors eg. healthcare, education, diet

Question 4

What is indirect transmission?

Answer 4

when a disease is transmitted between organisms via an intermediate eg. air, water, food or vectors

Question 5

What are 4 methods of disease transmission?

Answer 5

-direct physical contact
-faecal-oral transmission
-droplet infection
-spore transmission

Question 6

Direct physical contact: type of transmission, examples of diseases, how to reduce

Answer 6

-direct transmission
-HIV spread via sexual intercourse
-Athlete’s foot spread via touch
-increase level of healthcare to diagnose and treat people
-increase health education to encourage safe practice

Question 7

Faecal-oral transmission:
type of transmission, examples of diseases, how to reduce

Answer 7

-indirect transmission
-cholera spreads by consuming food/water contaminated by infected person
-better sewage/drainage/water systems

Question 8

Droplet infection: type of transmission, examples of diseases, how to reduce

Answer 8

-direct and indirect
-TB spread via droplet infection (sneezing mucus at someone etc), bacteria can remain in air for long periods so also indirect
-reduce overcrowding
-wear masks in epidemics

Question 9

Spore transmission: type of transmission, examples of diseases, how to reduce

Answer 9

-indirect transmission
-potato/tomato blight spreads when spores are carried between plants
-blight especially common in wet summers, as spores need water to spread
-keep plants inside or in dry areas
-use mosquito nets for protists

Question 10

How does a poor diet increase disease transmission?

Answer 10

lack of proper nutrition weakens the immune system

Question 11

How does poor healthcare increase disease transmission?

Answer 11

people are less likely to be diagnosed and treated, virus can be passed on

Question 12

How does poor education increase disease transmission?

Answer 12

people are less knowledgeable and therefore are more likely to catch disease as they don’t know how it’s transmitted and how to avoid it

Question 13

How does overcrowding increase disease transmission?

Answer 13

many people living in close proximity means disease can pass between them-physical touch/through air

Question 14

How does a hot and wet climate increase disease transmission?

Answer 14

-spores need water to spread
-mosquitos breed in humid, hot areas

Question 15

What is plasmodium?

Answer 15

-pathogen carried by a mosquito (vector) to cause malaria

Question 16

How does plasmodium cause malaria?

Answer 16

-when an infected female mosquito bites someone, plasmodium parasites, in the form of ‘sporozoites’ are injected into the blood stream

Question 17

How do plants directly transmit pathogens?

Answer 17

-contact between diseased and healthy leaves (TMV)
-windblown rain or dust

Question 18

How do plants indirectly transmit pathogens?

Answer 18

-viruses are carried in pollen or by insects (vectors include aphids, leafhoppers, whiteflies, grasshoppers)
-other animals could act as vectors: slugs, snails, birds, dogs, rabbits