Study_guide_Exam_3

Microbial Pathogenicity

The ability of a microorganism to cause disease.

Signs vs Symptoms

Signs are objective evidence of disease (e.g., fever), while symptoms are subjective experiences (e.g., pain).

Classification of Diseases

Diseases can be classified as infectious, genetic, or environmental.

Acute Disease

A disease characterized by a rapid onset and a short duration.

Chronic Disease

A disease that persists over a long time and typically has a slow progression.

Latent Disease

A disease that is inactive for a period and may reactivate later.

Normal Human Flora

Microorganisms that normally reside in the human body without causing disease.

Transient Flora

Temporary microorganisms that may be present in or on the body.

Resident Flora

Microorganisms that are permanently established in the body.

Sterile Anatomical Sites

Areas of the body that normally don't contain any microorganisms.

Disruption of Normal Flora

Changes in the normal microbial community can lead to disease.

Pathogens

Microorganisms that can cause disease.

Virulence

The degree of pathogenicity and severity of disease caused by a pathogen.

Endogenous Infection

An infection that arises from organisms already present in the body.

Opportunistic Infection

An infection caused by pathogens that take advantage of a host with a weakened immune system.

Infectious Dose (ID)

The minimum number of pathogens required to cause an infection.

Pathogenesis Steps

The sequence of events that occur when pathogens infect tissues: contact, adhesion, establishment, movement to sterile tissues, and damage.

Virulence Factors

Molecules produced by pathogens that contribute to their ability to cause disease.

Endotoxins vs Exotoxins

Endotoxins are part of the cell wall of Gram-negative bacteria; exotoxins are secreted into the surrounding environment.

Local Infection

An infection confined to a specific area.

Systemic Infection

An infection that spreads throughout the body.

Focal Infection

An infection that starts in one area but spreads to other areas.

Asymptomatic Infection

An infection that does not produce noticeable symptoms.

Primary Infection

The first infection caused by a pathogen.

Secondary Infection

An infection that occurs after a primary infection.

Portals of Exit

Ways in which pathogens leave the host to spread to others.

Patterns of Infectious Disease Occurrence

Patterns include endemic (constant presence), epidemic (sudden increase), and pandemic (widespread outbreak).

Reservoir

The natural habitat of a pathogen where it lives and multiplies.

Definitive Host

The host in which a parasite reaches maturity and reproduces.

Intermediate Host

A host that harbors the parasite during some transitional stage.

Source

The immediate origin of the pathogen.

Carrier

An asymptomatic individual who harbors the pathogen and can transmit it.

Transmission Modes

Include contact (direct & indirect), vehicle, and vector transmission.

Healthcare-associated Infections (HAI)

Infections acquired in healthcare settings.

Nosocomial Infections

Infections acquired in a hospital or healthcare facility.

Innate Immunity

The non-specific first line of defense against pathogens.

Adaptive Immunity

The specific immune response tailored to a particular pathogen.

1st Line of Defense

Physical and chemical barriers (e.g., skin and mucous membranes).

2nd Line of Defense

Non-specific immune responses, including inflammatory response and fever.

3rd Line of Defense

Specific immune responses involving B and T lymphocytes.

WBCs (White Blood Cells)

Cells involved in the immune response; include granulocytes and agranulocytes.

Differentiation of Blood Cells

Process by which hematopoietic stem cells develop into different types of blood cells.

Diapedesis

The movement of white blood cells out of the circulatory system into tissues.

Chemotaxis

Movement of cells towards a chemical stimulus often in response to infection.

Pathogen Recognition

The identification of pathogens by the immune system.

Inflammatory Response

A localized response to injury or infection that involves the recruitment of immune cells.

Fever

An elevation of body temperature that aids in the immune response.

Phagocytosis

The process by which a cell engulfs particles or pathogens.

Interferons

Proteins released by host cells in response to viral infections to aid in defense.

Complement System

A series of proteins that enhance the ability of antibodies and phagocytes to clear pathogens.

Humoral Immunity

Immune response mediated by B cells and antibodies.

Cell-mediated Immunity

Immune response mediated by T cells.

Antigens

Substances that induce an immune response.

Epitopes

Specific regions on antigens that are recognized by immune cells.

Haptens

Small molecules that can induce an immune response only when attached to a larger carrier.

Antibodies/Immunoglobulins

Proteins produced by B cells that recognize and bind to specific antigens.

Structure of an Antibody

Consists of a Y-shaped structure with variable and constant regions.

5 Classes of Immunoglobulins

IgM, IgG, IgA, IgE, and IgD, each with different functions.

Antigen-antibody reactions

Interactions between antibodies and antigens that neutralize pathogens.

MHC Molecules

Major histocompatibility complex molecules that present antigens to T cells.

MHC Class I

Molecules found on all nucleated cells that present antigens to cytotoxic T cells.

MHC Class II

Molecules found on antigen-presenting cells that present antigens to helper T cells.

Antigen-Presenting Cells (APCs)

Cells that process and present antigens to T cells, such as dendritic cells.

Development of Lymphocytes

The process by which B and T cells develop and mature in the immune system.

B-cell Receptors

Molecules on B cells that bind to specific antigens.

T-cell Receptors

Molecules on T cells that recognize antigens presented by MHC molecules.

Helper T Cells

T cells that help activate B cells and cytotoxic T cells.

Cytotoxic T Cells

T cells that kill infected or cancerous cells.

T cell-independent Activation

Activation of B cells without T cell help, often by large antigens.

T cell-dependent Activation

Activation of B cells that requires assistance from helper T cells.

Clonal Selection

The process by which specific B or T cells are activated and proliferate in response to an antigen.

Primary Response to Antigens

The first response of the immune system to a specific antigen.

Secondary Response to Antigens

A faster and stronger immune response upon subsequent exposure to the same antigen.

Categories of Acquired Immunity

Natural (from infection) vs artificial (from vaccination), active (producing antibodies) vs passive (receiving antibodies).

Vaccine

A preparation that provides immunity to a specific infectious disease.

Classes of Vaccines

Include live-attenuated, inactivated, subunit, and mRNA vaccines.

Herd Immunity

Protection of unvaccinated individuals in a population due to high vaccination rates.

Skin Lesions

Abnormal changes in the skin's color, texture, or appearance.

Staphylococcus aureus

A common bacterium that can cause skin infections.

Streptococcus

A genus of bacteria known for causing various infections, including skin infections.

Pseudomonas aeruginosa

A bacterium associated with skin infections, particularly in immunocompromised individuals.

Bacillus anthracis

The bacterium that causes anthrax, potentially leading to skin infections.

Bacterial Conjunctivitis

An infection of the conjunctiva often referred to as pinkeye.

Neonatal Conjunctivitis

Conjunctivitis occurring in newborns, often caused by bacterial infection.

Trachoma

A contagious bacterial infection of the eye that can lead to blindness.

Bacterial Keratitis

An infection of the cornea that can cause pain and vision loss.

Human Papillomavirus (HPV)

A virus that can lead to skin warts and certain cancers.

Human Herpesviruses

Viruses that can cause infections ranging from cold sores to chickenpox.

Human Parvoviruses

Viruses that can cause skin rashes and other symptoms.

Herpetic Keratitis

An infection of the eye caused by herpes virus.

Viral Conjunctivitis

An infection of the conjunctiva caused by viruses.

Fungal Infections/Mycoses

Infections caused by fungi affecting the skin and other body parts.

Tineas

A group of fungal infections commonly known as ringworm.

Cutaneous Aspergillosis

A fungal infection caused by the Aspergillus species, affecting the skin.

Candidiasis

A fungal infection caused by Candida species, often affecting mucous membranes.

Sporotrichosis

A fungal infection caused by Sporothrix schenckii, often affecting the skin.

Acanthamoeba Infections

Infections caused by the Acanthamoeba species, affecting the eyes and skin.

Loiasis

A parasitic infection caused by the Loa loa worm, affecting the eyes and skin.