Infection and Response Flashcards
Pathogen
A pathogen is a harmful microorganism that causes diseases.
Types of pathogens
Bacteria
Fungi
Viruses
Protists
Ways diseases are spread
Some examples: Air, Water, Lifestyle, Vector, Direct Contact
Controlling the spread of communicable diseases:
Vaccination
Isolation
Reducing Vectors
Hygiene
Bacteria
- Cause diseases in animals
- Single celled organisms
- Produce toxins
- Do not have a nucleus (prokaryotik)
Examples include: Gonorrhoea and Salmonella
Gonorrhoea
Bacteria: Sexually Transmitted (STD)
Symptoms: thick yellow discharge from genitals, pain when urinating.
Prevention and Treatment: antibiotics, protected sex
Salmonella
Bacteria - Digested bacteria from food
Symptoms: fever, vomiting, diarrhoea, cramps.
Prevention: poultry are vaccinated.
Fungi Example
Rose Black Spot:
Spread by water and air
Symptoms: purple or black spots on leaves which droop and fall. Reduces photosynthesis.
Treatment: fungicides, remove infected leaves.
Protist Example
Malaria:
Spread by mosquitos (VECTOR)
Symptoms: episodes of fever, can be fatal.
Prevention and Treatment: control vector, anti-malarial medication, mosquito nets, vaccination.
Viruses
- Cause diseases in all living things
- Smaller compared to bacteria
- Neither living or dead
- Invade cells and replicate themselves inside them, before
bursting out, killing the cell and damaging tissues in the
process.
Measles
Virus - spread by inhalation of droplets in the air
Symptoms: fever, rash, can be fatal
Treatments: vaccination (children)
HIV
Virus - Sexually Transmitted/ Blood/ Exchange of fluids (drug users)
Symptoms: flu-like symptoms; virus attacks the immune cells, which can lead to AIDS thus causing cancer and other serious diseases.
Prevention: protected sex; don’t do drugs or use someone else’s needle.
TMV
Virus - direct contact of plants/ vectors/ soil remains infected for long periods of time
Symptoms: mosaic pattern of discolouration as chlorophyll is destroyed. Reduces photosynthesis.
Prevention: remove infected plant, use new soil.
Plant Defences: Physical Barriers
- Cellulose cell walls: provide a barrier for infection
- Tough waxy cuticle: II
- Bark on trees: dead cells that can fall off and remove
bacteria and vectors.
Plant Defences: Chemical Barriers
- Antibodies
- Anti-bacterial chemicals
- Poison production: discourage herbivores