Infectious Diseases, Pandemics, and Prion Diseases

Comprehensive vocabulary flashcards covering basic biomedicine, historical germ theory, classification of infectious agents, transmission mechanisms, virulence factors, and prion diseases.

Biomedicine

A branch of science focused on understanding the biology of disease so that illnesses can be detected, treated, prevented, and/or cured.

Disease

A condition that occurs when an abnormality causes a loss of normal structure or function and consequently affects health.

Infection

The successful persistence and/or multiplication of a pathogen within or on a host.

Pathogen

An infectious microorganism that causes tissue damage or disease.

Asymptomatic Infection

A state in which an individual harbors a pathogen but shows no outward symptoms of disease.

Transmission

The mechanism by which an infectious disease moves between different individuals or hosts.

Pathogenesis

The process by which an infectious agent causes tissue damage to the host, resulting in disease and symptoms.

Miasma Theory

The historical belief that diseases were caused by bad air originating from unpleasant or contaminated environments.

Spontaneous Generation

The disproved belief that living organisms could arise directly from non-living material.

Koch's Postulates

A set of four experimental criteria used to establish a causal relationship between a specific microorganism and a disease.

Viruses

Extremely small infectious agents (approximately $20\text{--}300\text{ nm}$) that are obligate intracellular parasites and cannot replicate independently outside a host cell.

Tropism

The specific type of cell or tissue that a particular virus is able to infect.

Bacteria

Single-celled prokaryotic organisms that can generally survive outside host cells, reproduce independently, and synthesize their own proteins and nucleic acids.

Gram-Positive Bacteria

Bacteria with a thick peptidoglycan layer and a single cell membrane that appear purple under Gram staining.

Gram-Negative Bacteria

Bacteria with a thin peptidoglycan layer flanked by an inner and outer membrane that appear pink under Gram staining.

Pili

Bacterial surface structures primary used for attachment to cells or surfaces.

Flagella

Bacterial surface structures that enable cell movement.

Capsules

Bacterial surface structures that provide protection and aid in environmental survival.

Fungi

Eukaryotic organisms that exist as single rounded cells called yeasts or branching filamentous structures called hyphae.

Protozoa

Single-celled eukaryotic parasites, such as Plasmodium.

Helminths

Multicellular parasitic worms, such as hookworms, tapeworms, and nematodes.

Vector

An organism, such as a mosquito or flea, that transmits an infectious pathogen from one host to another.

Prion

An infectious misfolded protein lacking DNA or RNA that causes normal cellular proteins to misfold, leading to aggregation and neuronal damage.

Resident Flora

Microorganisms that naturally inhabit the body's skin, mucous membranes, and intestines without causing harm, helping prevent infection by occupying space.

Virulence Factors

Traits or properties of a pathogen—such as invasiveness, immune evasion, replication, toxin production, and adherence—that determine its degree or ability to cause damage.

Vertical Transmission

The spread of a pathogen directly from mother to child via the placenta during pregnancy, during birth, or through breastfeeding.

Kuru

A fatal neurological prion disease affecting the Fore people of Papua New Guinea, transmitted through the consumption of infected human brain and nervous tissue during funerary rituals.

Transmissible Spongiform Encephalopathies (TSEs)

A group of progressive, fatal prion diseases characterized by severe brain damage that gives brain tissue a sponge-like appearance.

Bovine Spongiform Encephalopathy (BSE)

A prion disease affecting cattle (commonly known as mad cow disease) that can transmit to humans through contaminated beef as variant Creutzfeldt-Jakob disease (vCJD).