HOST PARASITE RELATIONSHIP Flashcards
The HOST-PARASITE RELATIONSHIP
Infectious disease results from the
interaction of an _____
with the ___ in its particular
______
infectious agent
host
environment
The Host
Primary protective factor is RESISTANCE:
Four Types of Resistance
1)
2)
3)
4)
5)
1) Genetic or natural resistance
2) Species resistance
3) Age and Sex resistance
4) Immune resistance
5) nutritional
The Host
Primary protective factor is RESISTANCE:
Four Types of Resistance
1) Genetic or natural resistance
2) Species resistance
3) Age and Sex resistance
4) Immune resistance
a.
b.
A. Passive or Transferred Immunity
B .Active or Acquired Immunity
What are the three influential factors of an infectious agent?
- Virulence
- Tropism
- Ability to persist or to spread in the host
These factors determine how effectively an infectious agent can cause disease.
What are the nine influential factors of the environment affecting infectious agents?
- Ambient temperature
- Humidity
- Spacing
- Housing/Shelter
- Moisture
- Ventilation
- Lighting
- Feeds
- Various environmental pollutants
These environmental factors can significantly impact the survival and transmission of infectious agents.
Fill in the blank: The ability of an infectious agent to cause disease is known as _______.
[Virulence]
True or False: Tropism refers to the ability of an infectious agent to spread in the host.
False
Tropism specifically refers to the preference of an infectious agent for a particular host tissue.
Fill in the blank: The factor that includes ambient temperature and humidity is part of the _______ that influences infectious agents.
[Environment]
What does the term ‘moisture’ refer to in the context of environmental factors influencing infectious agents?
The presence of water in the environment that can affect the survival and spread of infectious agents
Moisture levels can influence microbial growth and viability.
How do bacteria generally cause disease?
Bacteria generally cause disease by:
* invasion
* production of toxins
* attaching or colonizing
* evading hosts defenses
These mechanisms can occur singly or in combination.
What are the main ways viruses cause disease?
Viruses generally cause disease by:
* cytolysis
* maintaining steady state with the host
* integrating into the genome of the host
Cytolysis refers to the destruction of cells, often leading to disease.
How do parasites generally cause disease?
Parasites generally cause disease by:
* local destruction of cells/tissues
* effects on blood circulation
* space-occupying lesions
* nutritive competition
These effects can lead to various diseases and health complications.
What are the ways fungi generally cause disease?
Fungi generally cause disease by:
* invasion of living tissue
* inducing allergies or hypersensitivities
* toxicosis
Toxicosis refers to the toxic effects caused by fungal metabolites.
How do toxins or poisons produce disease?
Toxins or poisons generally produce disease by:
* direct contact (causing sudden degeneration and necrosis)
* absorption (striking lesion is produced and derangement of metabolism)
Direct contact with toxins can lead to immediate tissue damage.
What is the general term for living together or co-existence of two organisms?
Symbiosis
Symbiosis can involve different types of relationships between organisms.
What are the three types of symbiotic relationships?
- Mutualistic
- Commensalistic
- Parasitic
Each type of relationship has different implications for the organisms involved.
True or False: Symbiosis only refers to harmful interactions between organisms.
False
Symbiosis encompasses beneficial, neutral, and harmful interactions.
Fill in the blank: Symbiosis may be __________, commensalistic, or parasitic.
[mutualistic]
Mutualism is a type of symbiosis where both organisms benefit.
What is a Parasitic Relationship?
A relationship whereby one partner lives at the expense of another.
Parasitism often involves one organism benefiting at the cost of another, which may suffer harm.
Define Commensalism.
A relationship in which there is advantage to one partner but no real disadvantage to the other.
In commensal relationships, one organism benefits while the other is neither helped nor harmed.
What is Mutualism?
A relationship in which two organisms live together without disadvantage nor harm to one another.
Mutualism benefits both organisms involved, often enhancing their survival or reproduction.
What is the chronologic sequence of events used by infectious microorganisms?
The sequence includes colonizing and invading mucosae and skin, spreading to local tissues, and causing disease.
This process is critical for understanding how infections develop and progress.
How do infectious microorganisms commonly enter the body?
Ingestion, inhalation, or cutaneous penetration.
These routes are essential for the initial stages of infection.
What do infectious microorganisms interact with upon entering the body?
Mucosae or skin.
This interaction is the first step in the infection process.
