Communicable Disease Flashcards
What is a communicable disease?
An infectious disease that can be passed from organism to organism
What are the 4 types of pathogen?
Bacteria
Virus
Fungi
Protoctista (protista)
What are bacterium?
They are prokaryotes as they have no membrane-bound organelles.
They can be spherical, rod-shaped or corkscrew in shape.
They also have a cell wall (cellulose)
What is the process by which bacteria reproduce called?
Binary fission
What are viruses
They are regarded as non-living and are 50x smaller than the average bacteria.
They use host cells to reproduce rapidly and evolve accordingly to their host.
What are protoctista/protista?
They are eukaryotic organisms. A small group of of protoctista act as pathogens. They are parasites which means they use the host organism for their own benefit.
What is TB and who does it affect?
It affects humans, cattle and other animals
It is a bacteria
What is ring rot and who does it affect?
It affects potatoes and tomatoes
It is a bacterium
What is HIV/aids and who does it affect?
It is a virus that only affects humans
What is influenza and who does it affect?
Influenza is a virus that affects animals and humans
What is tobacco mosaic virus and who does it affect?
Tobacco mosaic virus (TMV) is a virus that affects plants
What is black sigatoka and who does it affect?
It is a fungi that only affects bananas plants
What is athletes foot and who does it affect?
It is a fungi that affects humans
What is potato/tomato blight and who does it affect?
It is a protoctist that affects potatoes and tomatoes
What is malaria and who does it affect?
It’s a protoctist that affects animals and humans
How do pathogens cause disease?
Damaging host cells or tissues directly
Producing toxins which damage host tissues
What are exotoxins?
Toxins produced and secreted by a normal pathogen
What are endotoxins?
They are toxins that are produced when a pathogen is damaged and toxins are released
Can fungi photosynthesise?
They can’t photosynthesise. They must digest their food extracellularly before absorbing nutrients. They are sacrophytes which means they feed on dead and decaying matter.
What are the two types of disease transmission?
Direct and indirect transmission
What is direct transmission?
The pathogen/disease is transmitted from one organism to another
What are examples of direct transmission?
Physical contact (sexual intercourse)
Droplet infection (coughing/sneezing)
Inoculation (break in skin/needle use)
Ingestion (eating contaminated food)
How can you reduce the risk of direct transmission?
Washing hands regularly
Cleaning and disinfecting cuts
Sterilising surgical instruments
Using condoms
What is indirect transmission?
When a disease is transmitted from one organism to another via and intermediate (vectors or fomites)
What is a vector?
An organism that spreads disease by carrying the pathogen
What is a fomite?
Inanimate objects that harbour and transfer disease
What factors affect transmission?
Living conditions (over-crowding, poor nutrition, poor disposal of waste)
Social factors (traditional remedies can increase transmission, poorly trained health workers)
Climate change
What is a zoonosis?
A zoonosis/zoonotic disease is an infectious disease that is transmitted from animals to humans
Eg. Swine flu
How can pathogens be transmitted to other plants?
Direct transmission (contact of a healthy plant with any part of an infected plant)
Vectors (soil contamination, wind, water, contaminated farming tools)
In plants where does the fungus often live?
The fungus often lives in the vascular tissue to easily acquire nutrients.
They hyphae releases extracellular enzymes to digest surrounding tissue causing decay.
What is a pathogen?
A disease-causing organism
Give an example of a disease caused by a protoctist?
Malaria
What are passive defences in plants?
They are defences against pathogens that are always present