Infectious Diseases and Pathogens Vocabulary

Vocabulary flashcards generated from lecture notes covering infectious disease fundamentals, Koch's principles, pathogens, viral replication, and structural characteristics of viruses, bacteria, fungi, and protists.

Infectious Disease

Any condition that interferes with the normal function of an organism or any part of it, caused by an invasion by a pathogen, and able to be transmitted from host to host.

Host

An organism infected with a pathogen.

Infection

The condition occurring when a pathogen has entered a host, established itself, and is replicating.

Pathogen

An organism that causes infectious disease.

Contagious Disease

An infectious disease able to be transmitted directly from an infected host to a susceptible host.

Koch's Principles

A four-step set of criteria used to identify the specific cause of an infectious disease by isolating, culturing, inoculating, and re-isolating a potential pathogen.

Zoonotic Disease

A disease that can exist in one vertebrate group and enter a different group, such as influenza in the form of swine flu or bird flu.

Incubation Period

The time between initial infection and the appearance of symptoms.

Virulence Factors

Traits that determine the pathogenicity of an organism, including surface coats that inhibit phagocytosis, surface proteins that help bind to host cells, and the type of toxin produced.

Pathogenicity

The capacity for a pathogen to cause disease in a host.

Virulence

A measure of the severity of the disease caused by a pathogen.

Obligate Parasite

A parasite that depends entirely on a host for its life cycle and reproduction.

Australian Bat Lyssavirus (ABL)

A viral pathogen that attacks the central nervous system, traveling to the brain and causing inflammation, paralysis, delirium, convulsions, and death.

Viral Specificity

The requirement of a virus to attach to specific receptor molecules on the surface of host cells, determining which cells it can infect.

Hyphae

Long, thin, multipolar filaments with strong tubular cell walls surrounding a cell membrane that provide a high surface area for absorption in fungi.

Mycelium

A network of hyphae that makes up the body of a fungus.

Sporangia

Structures formed by mature fungal mycelium that release sexual or asexual spores.

Endospores

Resistant structures formed by bacteria that enable survival under extreme temperatures, chemicals, and drying out.

Bacterial Capsule

A slimy outer layer possessed by some bacteria that acts as a virulence factor.

Protozoa

Animal-like protists that lack chlorophyll and cell walls.

Plasmodium

A genus of animal-like protists (protozoa) that spread through their hosts in the form of tiny infectious cells called sporozoites.

Phytophthora

A genus of plant-resembling protists featuring cellulose-based cell walls and plural flagella.

Encysting

The process by which protists form thick cell walls around resistant cysts to enable survival and transmission beyond a host.

Viruses

Microscopic ($30\text{--}300\,nm$), non-cellular pathogens composed of a protein coat (capsid) and nucleic acid (either double-stranded DNA or single-stranded RNA, but never both) that rely on host cells to replicate.