Untitled Deck Flashcards
Define disease
A condition that impairs the normal functioning of an organism.
Define pathogen
Organism that causes disease.
e.g. bacteria, viruses, fungi and protoctists (type of single-celled eukaryotic organism).
What is a communicable disease?
A disease that can spread between organisms.
Examples of diseases caused by bacteria
Tuberculosis, bacterial meningitis, ring rot
Bacterial meningitis —> humans; Ring rot —> potatoes, tomatoes.
Examples of diseases caused by viruses
HIV/AIDS, influenza, TMV.
Influenza —> animals+humans; Tobacco mosaic virus (TMV) —> plants.
Examples of diseases caused by fungi
Black sigatoka, ringworm.
Ringworm —> cattle; Athlete’s foot —> humans.
Examples of diseases caused by protoctists
Potato/tomato late blight, malaria
Malaria —> animals+humans.
How can communicable diseases be spread?
Direct and indirect transmission.
What is direct transmission?
Disease transmitted directly from one organism to another.
Includes droplet infection, sexual intercourse, touching an infected organism.
Examples of direct transmission diseases
HIV transmitted between humans via sexual intercourse and from a mother to unborn child through placenta.
Athlete’s foot spread via touch.
What is indirect transmission?
When a disease is transmitted from one organism to another via an intermediate, including air, water, food, or vector.
Examples of indirect transmission diseases
Potato/tomato late blight spreads when spores are carried between plants - first in the air, then in water.
Malaria spreads between humans + animals via mosquitoes (insects that feed on blood).
Factors affecting transmission of disease
Living conditions, social factors, climate.
