Transmission of Pathogens Flashcards
Define direct transmission.
Passing a pathogen from host to new host, with no intermediary.
Define indirect transmission.
Passing a pathogen from host to new host via a vector.
What is a transmission?
Passing a pathogen from an infected individual to an uninfected individual.
What is a vector?
An organism that carries a pathogen from one host to another.
What are the four stages in the lifecycle of a pathogen ?
Travel form one host to another (transmission)
Entering the host’s tissue
Reproducing
Leaving the host’s tissue
What are the four main means of direct transmission?
Give an example of each.
Direct physical contact. HIV
Faecal-oral transmission. Cholera
Droplet infection. Tuberculosis or influenza
Transmission by spores. Anthrax
List the social factors that affect transmission.
Overcrowding Poor ventilation Poor health Poor diet Homelessness Living or working with people form diseased areas.
Indirect transmission of a disease is spread via what?
A vector
How does malaria enter a human?
Via the female anopheles mosquito.
How are plant pathogens spread?
Spores may be carried in the wind and are therefore airborne.
Many pathogens are present in the soil.
How are plant pathogens spread using fruit and leaves?
If the pathogen reaches the fruit or leaves in a plant then once the leaves are shed and the fruit fall the pathogen is able to spread and grow via the soil again.
How does indirect transmission of plant pathogen occur?
Usually via insect attack. Insects who have attacked an infected plant will carry the pathogen, usually spores, on their body. The insect then goes to attack another plant causing the pathogen to now spread onto this plant.
How does disease and climate affect transmission?
Many protoctista spread faster in warm and moist climates therefore those in warmer climates have a wider variety of diseases.
