extensive infectious diseases

Disease

Any condition that interferes with how an organism functions.

Infection

The invasion of a host by a pathogen where it establishes itself and replicates.

Pathogen

A disease-causing agent.

Infectious Disease

A disease caused by a pathogen that can be transmitted from one host to another.

Koch's Postulates

A series of steps used to identify the specific cause of an infectious disease.

Virulence

A measure of the ability and intensity of a pathogen to cause severe disease.

Four Main Types of Pathogens

Viruses, bacteria, fungi, and protists.

Transmission

The passing of an infectious disease from an infected host to another individual.

Contagious

Able to be transferred by direct contact.

Zoonotic Disease

An infectious disease that can be transmitted between vertebrate groups and humans.

Outbreak

A sudden unexpected increase in the prevalence of a disease above baseline levels.

Three Factors of Transmission

The infectious agent, a susceptible host, and the mode of transmission.

Incubation Period

The time lag between infection and the onset of symptoms.

Virus Structure

A non-cellular agent composed of nucleic acid (DNA or RNA) inside a protein coat.

Lysis

The process of a host cell bursting, releasing viral particles.

Obligate Parasite

An organism that can only survive and replicate inside another living organism.

Bacteriophage

A virus that infects and invades bacteria.

Capsid

The protective protein coat of a virus.

Bacterial Characteristics

Unicellular prokaryotes lacking a nucleus or organelles, with a peptidoglycan cell wall.

Bacterial Plasmids

Small loops of DNA that can carry advantageous genes and transfer between bacteria.

Bacterial Capsules

Slimy outer layers that help bacteria stick to surfaces and evade immune attacks.

Endospores

Resistant structures formed by some bacteria to survive extreme temperatures and drying.

Bacterial Shapes

Spherical (coccus), rod-shaped (bacillus), spiral, and comma-like (vibrio).

Phagocytosis

The process where a white blood cell engulfs and destroys a microbe.

Macrophage

A white blood cell that performs phagocytosis to destroy foreign microbes.

Mycobacterium tuberculosis

A bacterium causing TB that can survive, replicate, and evade lung macrophages.

Agrobacterium tumefaciens

A plant pathogen that inserts plasmid DNA into host cells, causing crown gall tumors.

Fungal Cell Walls

Rigid outer structures made of chitin surrounding eukaryotic fungal cells.

Mycelium

An interwoven mass of hyphae that forms the main body of a fungus.

Protists

Mostly unicellular eukaryotes with membrane-bound organelles, a few of which are pathogenic.

Portal of Entry and Exit

The specific route through which a pathogen enters or leaves a host organism.

Mucous Membranes

Moist epithelial linings of respiratory, gastrointestinal, and reproductive tracts acting as portals of entry.

Vectors

Living organisms, typically arthropods, that transfer pathogens between different hosts.

Ross River Virus

An Australian alphavirus transmitted indirectly to humans by female mosquitoes from marsupial reservoirs.

Chytridiomycosis

A fungal disease caused by Batrachochytrium dendrobatidis that attacks amphibian skin layers.

Malaria Transmission

Caused by Plasmodium protists, transmitted indirectly via the bite of female Anopheles mosquitoes.

Phytophthora Dieback

A soilborne plant protist that attacks root systems and causes fatal root rot.

Disease Spread Thresholds

Critical levels of host density, pathogen size, and transmission needed for disease spread.

Yes — I’ve broken each disease into smaller, more focused flashcards while keeping the same information. Each line is Term → Definition, separated by a tab, so you can paste it directly into Quizlet.

Ross River virus disease — pathogen type

RNA virus

Ross River virus disease — pathogen name

Ross River virus

Ross River virus disease — most common transmission

Indirect via female mosquito vector, e.g. Aedes vigilax

Ross River virus disease — entry

Via skin (blood feed)

Ross River virus disease — replication

In epithelial cells of mosquito vector and muscle cells of the infected human host before entering the bloodstream and then multiplying there

Ross River virus disease — reservoir

Marsupials (e.g. wallabies)

Ross River virus disease — entry and exit

Via two different blood feeds

Ross River virus disease — exit

Not likely from human host; pathogen circulates through marsupials such as the western grey kangaroo

Deformed wing virus disease — pathogen type

Virus

Deformed wing virus disease — pathogen name

Deformed wing virus

Deformed wing virus disease — indirect transmission

Indirect via the vector varroa mite

Deformed wing virus disease — direct transmission

Direct via vertical transmission from bee to offspring

Deformed wing virus disease — entry and exit

Via skin (blood feeds from varroa mite vectors)

Deformed wing virus disease — replication

In bee

Australian bat lyssavirus — pathogen type

RNA virus

Australian bat lyssavirus — pathogen name

Australian bat lyssavirus

Australian bat lyssavirus — transmission

Direct contact with an infected bat’s bodily fluids, through a bite or scratch

Australian bat lyssavirus — entry

Via site of bite or other break in skin

Australian bat lyssavirus — replication

In bat reservoir and infected human host before travelling along nerves to CNS

Australian bat lyssavirus — exit

Not likely from human host; pathogen circulates through bats

Tuberculosis — pathogen type

Bacterium

Tuberculosis — pathogen name

Mycobacterium tuberculosis

Tuberculosis — direct transmission

Direct, close contact via airborne droplets inhaled into respiratory system

Tuberculosis — indirect transmission

Indirect if the droplets land on a dusty fomite, become disturbed and are then inhaled

Tuberculosis — entry

Via respiratory system

Tuberculosis — replication

In alveolar macrophages in lungs

Tuberculosis — exit

Via respiratory system through a cough or sneeze

Tetanus — pathogen type

Bacterium

Tetanus — pathogen name

Clostridium tetani

Tetanus — transmission

Direct contact between soil reservoir and deep puncture wound

Tetanus — entry

Via deep wound

Tetanus — replication

In tissue in a deep wound in the absence of oxygen

Tetanus — neurotoxin action

The neurotoxins travel up neurons, blocking the release of inhibitory neurotransmitters in the CNS

Crown gall — pathogen type

Bacterium

Crown gall — pathogen name

Agrobacterium tumefaciens

Crown gall — indirect transmission

Indirect soilborne spores via a root wound, or via a vehicle such as grafting or other gardening tools

Crown gall — direct transmission

Direct contact via infected root to wound on susceptible plant root

Crown gall — entry

Via a wound on a susceptible plant root

Crown gall — replication

In plant roots

Crown gall — bacterial action

Bacteria transfer some plasmid DNA into the plant cell genome

Crown gall — effect of inserted DNA

The inserted DNA codes for uncontrolled plant growth

Crown gall — gall formation

Plant cells grow and divide and form galls

Crown gall — exit

Via galls, through spores that drop into the soil or onto vehicles for further spread

Chytridiomycosis — pathogen type

Fungus

Chytridiomycosis — pathogen name

Batrachochytrium dendrobatidis

Chytridiomycosis — indirect transmission

Indirect via soilborne/waterborne swimming zoospores

Chytridiomycosis — direct transmission

Direct contact via infected amphibian skin to susceptible amphibian skin

Chytridiomycosis — entry

Via skin penetration (invades outer layer of skin/epithelium)

Chytridiomycosis — replication

Via asexual reproduction inside the thallus (zoosporangium)

Chytridiomycosis — exit

Via zoospores going from the thallus in the skin of an amphibian into the water

Malaria — pathogen type

Protist

Malaria — pathogen name

Plasmodium falciparum

Malaria — transmission

Indirect via female Anopheles mosquito vector blood feeds

Malaria — entry

Via skin: blood feed by mosquito vector