Transmission of disease medium
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Questions and Answers

What type of transmission involves the transfer of pathogens from mother to child?

  • Vertical transmission (correct)
  • Indirect transmission
  • Direct transmission
  • Horizontal transmission

    • Which of the following is an example of indirect transmission of disease?

  • Sharing a drink with someone
  • Kissing an infected person
  • Touching a contaminated surface (correct)
  • Having unprotected sex

    • What characteristic of pathogens is true regarding direct transmission?

  • Pathogens can survive outside a host for extended periods
  • Pathogens require physical contact for transmission (correct)
  • Pathogens can travel through vectors
  • Pathogens can be transmitted via droplets

    • Which of the following describes horizontal transmission?

    <p>Spread of pathogens between individuals in the same population</p> Signup and view all the answers

    Which mode of transmission cannot survive outside a host for very long?

    <p>Direct transmission</p> Signup and view all the answers

    What is the first step in Koch's postulates regarding pathogen transmission?

    <p>Leave an infected host</p> Signup and view all the answers

    Which component is NOT part of the chain of transmission?

    <p>Treatment</p> Signup and view all the answers

    Which of the following best describes a 'reservoir' in the context of disease transmission?

    <p>A location where pathogens can live and multiply</p> Signup and view all the answers

    Direct transmission of disease can occur through which of the following methods?

    <p>Physical contact with an infected individual</p> Signup and view all the answers

    Which of the following is an example of an indirect transmission route?

    <p>Bacteria transferred via fecal contamination</p> Signup and view all the answers

    Which form of transmission involves coughing, sneezing, or talking?

    <p>Droplet transmission</p> Signup and view all the answers

    Which of the following is an example of indirect transmission of disease?

    <p>Contaminated water</p> Signup and view all the answers

    What characteristic do droplets need to have to facilitate airborne transmission?

    <p>They must be small enough to remain suspended for long periods.</p> Signup and view all the answers

    What is the main route of disease transmission through water?

    <p>Water contaminated by excreta</p> Signup and view all the answers

    Which disease is NOT typically transmitted through droplets?

    <p>HIV</p> Signup and view all the answers

    Which of the following accurately describes vectors in disease transmission?

    <p>They are organisms that carry and transmit pathogens.</p> Signup and view all the answers

    What factor makes droplets suitable for settling out of the air?

    <p>Their large size and weight</p> Signup and view all the answers

    Which of the following represents a vehicle for indirect transmission?

    <p>Airborne dust</p> Signup and view all the answers

    How do microorganisms survive in droplets suspended in air?

    <p>By resisting drying and surviving outside the body</p> Signup and view all the answers

    Which of the following is NOT a type of vehicle for disease transmission?

    <p>Insects</p> Signup and view all the answers

    Study Notes

    Koch's Postulates

    • To persist, pathogens must leave an infected host, survive transmission, enter a susceptible host, and develop/multiply within the new host.

    Chain of Transmission

    • Requires an agent (pathogen), reservoir (where it lives), exit route, transmission mode, entry portal, and susceptible host.

    Classifying Transmission

    • Horizontal: Person-to-person
    • Vertical: Mother-to-child

    Direct and Indirect Transmission

    • Direct: Physical contact (kissing, touching)
    • Indirect: Through objects or vectors (air, water, food, fomites, vectors). Pathogen survival time outside the host dictates transmission type.

    Indirect Transmission: Vehicles

    • Air/droplets (e.g., tuberculosis, measles): Airborne transmission for pathogens resistant to drying. Droplets quickly settle, unlike dust particles
    • Water (e.g., typhoid): Contamination via human/animal excreta.
    • Soil (e.g., tetanus): Spores survive for long periods, transmitting intestinal worms.
    • Food (e.g., salmonella): Contamination often via food handlers with poor hygiene.
    • Fomites (inanimate objects): Indirect contact transmission.

    Indirect Transmission: Vectors

    • Insects: Many diseases are caused by organisms transmitted through insect bites or feces and secretions. Mosquitos (malaria, West Nile virus, etc.) represent a significant vector. Soil is sometimes considered to act as a vector
    • Accounts for 4.1% of global disease burden, causing 1.8 million deaths annually.

    Host Defense Mechanisms: Preventing Ingress

    • Mucociliary escalator: Mucus and cilia in the respiratory tract trap and remove microbes.
    • Skin: Keratinized outer layer acts as a physical barrier, except for unkeratinized areas (alimentary and respiratory tracts, eyes, gingival sulcus).
    • Fatty acids and salts (skin secretions): Kill bacteria.
    • Saliva: Contains antibacterial agents and has a lavage effect.
    • Gingival crevicular fluid: Antibacterial solution with immunological defense mechanisms.
    • Blood: Flushing action and clotting mechanisms prevent infection spread.
    • Blood-brain barrier: Specialized filter protecting the brain and spinal cord.

    Host Defense Mechanisms: Dealing with Ingress

    • Immune response: Recognizes and destroys foreign substances, distinguishing between self and non-self. Memory cells facilitate faster responses upon re-exposure to antigens. This varies based on lifestyle factors such as diet, smoking, and stress.

    Immune System Cells: Lymphocytes

    • White blood cells circulating in the lymphatic system.
    • B lymphocytes: Produce antibodies (immunoglobulins) for humoral immunity. Plasma cells produce antibodies, memory cells provide long-term immunity.
    • T lymphocytes: Control immune response and destroy antigens directly (cell-mediated immunity).

    Host Response to Biofilms

    • Inflammation (redness) indicates biofilm presence. Oral hygiene removes biofilm.

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    Related Documents

    Transmission of Disease GN PDF

    Description

    Explore Koch's Postulates and the various methods of pathogen transmission in this comprehensive quiz. Learn about direct and indirect transmission routes, including vehicles like air, water, and soil. Improve your understanding of how pathogens survive and spread.

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