Micro W8 Part 4: Infectioius Diseases & Chain of Infection

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Questions and Answers

What is the primary role of a reservoir in the chain of infection?

To eliminate pathogens from the environment

To house the infectious agents permanently (correct)

To provide a means of transmission to a susceptible host

To act as a portal of exit for pathogens

Which of the following is an example of a nonliving reservoir?

Animals infected with zoonotic diseases

Infected human carriers

Soil in which pathogens thrive (correct)

Houses where humans live

What is a zoonosis?

A type of orthopedic infection

A disease that can be transmitted from animals to humans (correct)

A disease that only affects humans

An infection caused by airborne pathogens

How can pathogens exit the human body?

Through excretions and secretions Signup and view all the answers

What defines direct contact transmission?

Physical contact between infected and non-infected individuals Signup and view all the answers

What categorizes indirect contact transmission?

Pathogens spread via non-living objects known as fomites Signup and view all the answers

Which mode of transmission is primarily associated with respiratory droplets?

Droplet transmission Signup and view all the answers

What is meant by the term 'auto/self-inoculation'?

Infecting oneself by transferring pathogens from one part of the body to another Signup and view all the answers

How is airborne transmission primarily facilitated?

Via tiny droplets or dust particles. Signup and view all the answers

What is a major source of vehicle transmission through waterborne means?

Contaminated water sources. Signup and view all the answers

Which of the following is NOT considered a method of foodborne transmission?

Inhalation of contaminated air. Signup and view all the answers

Which type of vector transmission involves insects carrying pathogens inside them?

Biological vectors. Signup and view all the answers

What role do mucous membranes play in the context of pathogen entry?

They serve as primary portals for pathogens. Signup and view all the answers

What type of pathogens can commonly cause gastrointestinal diseases through waterborne transmission?

Bacteria, viruses, and protozoa. Signup and view all the answers

Which entry point for pathogens typically has the highest risk of infection?

Respiratory tract. Signup and view all the answers

Which of the following describes endogenous sources of infection?

Pathogens that originate from altered normal flora. Signup and view all the answers

Which is an example of a portal of entry that bypasses normal barriers?

Parenteral route. Signup and view all the answers

What is the primary reason healthcare workers need to take precautions when handling bodily fluids?

To prevent transmission of pathogens. Signup and view all the answers

Study Notes

Reservoirs of Infection

Nonliving Reservoirs: Include soil, water, and food. Provide environments for pathogens like fungi, helminths, and bacteria.
Animal Reservoirs: Zoonoses are diseases primarily found in animals but transmissible to humans. Transmission occurs through direct contact, contaminated food/water, inhalation of dust, or insect vectors.
Human Carriers: Infected individuals who show no symptoms but can still spread the infection.

Portal of Exit

The point where a pathogen leaves an infected person.
Often the same as the portal of entry.
Pathogens exit through excretions (e.g., feces) or secretions (e.g., saliva, mucus).

Modes of Transmission

Contact Transmission

Direct Contact: Physical contact between individuals without an intermediate object (e.g., touching, kissing, sexual intercourse).
Indirect Contact Transmission: Pathogens spread through non-living objects called fomites (e.g., tissues, toys, medical equipment).

Vehicle Transmission

Airborne Transmission: Tiny droplets carrying germs travel through the air, including dust.
Bodily Fluid Transmission: Germs spread through blood, urine, saliva, and other fluids.
Waterborne Transmission: Germs spread through contaminated water.
Foodborne Transmission: Germs spread through contaminated food.

Vector Transmission

Biological Vectors: Insects carry the pathogen inside their bodies and provide an environment for its growth and development (e.g., mosquitoes, ticks).
Mechanical Vectors: Insects passively transport germs on their bodies (e.g., flies).

Portals of Entry

Definition: Sites where pathogens enter the body.
Sources of Infection:
- Exogenous: Pathogens come from outside the body.
- Endogenous: Pathogens originate within the body.
Common Areas: Skin, respiratory tract, mucous membranes.
Preferred Entry: Most pathogens have a specific portal of entry, while some can use multiple portals.
Portals of Entry:
- Skin: Natural openings (hair follicles, sweat glands) or breaks in the skin (abrasions, cuts).
- Mucous Membranes:
  - Gastrointestinal (GI): Pathogens enter through food, liquids, and ingested substances.
  - Respiratory Tract: Pathogens enter through air, dust, droplets.
  - Urogenital Tract: Often spread through sexual contact.
  - Conjunctiva: Bacteria can attach and infect this membrane.
- Placenta: Some pathogens can cross the placenta and harm the fetus.
- Parenteral Route: Bypass normal barriers by introducing pathogens directly into tissues through punctures, cuts, bites, wounds, or surgery.