a poisonous chemical, produced by certain pathogens
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What is the immune system?
the body's defence system against infections and diseases (consists of white blood cells and antibodies)
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What is immunity?
the ability to attack a pathogen before it causes disease due to a previous encounter with the pathogen
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What is an infection?
The presence of microorganisms causing damage to body tissues
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What is a microorganism?
Any organism too small to be seen by the naked eye
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What is endogenous infection?
an infection or disease that originates within the body
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What is exogenous?
an infection or disease that originates outside the body
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What is nosocomial infection?
an infection acquired by an individual in a health care facility, transmitted by healthcare workers
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What is an opportunistic infection?
an infection that occurs when the body's defenses are weak
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Define the term 'Chain of Infection'
refers to conditions that are met for disease to occur
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What does the chain of infection consist of?
1. Infectious agent
2. Reservoir
3.Portal of exit
4. Mode of transmission
5. Portal of Entry
6. Susceptible Host
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What is an infectious agent and what different forms can it be present as?
a pathogen, such as a bacterium or a virus that can cause disease
- Bacteria
- Fungi
- Virus
- Parasite
- Protozoa
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What is a reservoir?
The reservoir of an infectious agent is the habitat in which the agent normally lives, grows, and multiplies. These include:
- People
- Equipment
- Water
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What is a portal of exit?
a way for the infectious agent to escape from the reservoir in which it has been growing. For example through excretions, secretions and droplets
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What is the mode of transmission?
a way that the infectious agent can be transmitted to another reservoir or host where it can live. For example through direct contact, droplets, airborne or vector borne
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What is a portal of entry?
a way for the infectious agent to enter a new reservoir or host, such as, by the respiratory tract, GI tract, mucous membrane or by skin.
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What is a susceptible host?
a person likely to get an infection or disease, usually because the body defences are weak. This include:
- People with a chronic disease
- Immunocompromised
- Very young
- Elderly
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What is symbiosis?
is the way in which organisms live together for their mutual, and therefore, intrinsic benefit.
This benefits the human and not harm the microorganism.
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What is mutualism?
defined as an interaction between individuals of different species that results in positive (beneficial) effects
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What is commensalism?
is a type of relationship between two living organisms in which one organism benefits from the other without harming it.
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What are the four stages of progression (from the point of view of microorganism?
presence of a microorganism on/in a host, with growth and multiplication of the organism, but without interaction between host and organism
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What happens during the process of invasion?
- Infectious agents can invade surrounding tissues/ other sites
- Developed mechanisms to penetrate tissues & avoid the host's nonspecific & specific defences (inflammation & immunity)
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What happened during the process of multiplication?
- Warm, nutrient fills host environment
- Replicate within infected cells (viral pathogens)
- Replicate in macrophages & other cells (bacterial pathogens)
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What factors enable a successful spread?
- Adhesion molecules
- toxins
- protection against host's inflammatory and immune system
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What happens if the host has an intact immune system?
microorganism remains localised
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What happens is the host's immune or inflammatory system is compromised?
The infection may rapidly spread
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Other cards in this set
Card 2
Front
What is a toxin?
Back
a poisonous chemical, produced by certain pathogens
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