What should we care about infectious diseases?

Bile salts

A component of bile that helps in the digestion of food, but also prevents the growth of bacteria.

CDC

Centers for Disease Control and Prevention is a federal US public health agency.

Commensal microbiota

The microbes that reside within our bodies, which benefit from us, without harming us.

Contamination

The presence of impurities such as microbes.

Cross-protection

Protection conferred on a host by vaccination with one strain of a microorganism which later prevents infection by a slightly different strain.

Dose

The number of microbes that a host has been exposed to.

Epidemic

The abnormally rapid spread of an infectious disease to a large number of people in a given population within a short period of time.

Epithelia

Form the protective layer of the skin and mucosal membranes.

Host

The organism that the pathogen resides in.

Immune system

The defense system that protects the body by constant surveillance for intruders and killing those it encounters.

Microbe

An organism that is invisible to the naked eye.

Mortality

A measure of the number of deaths from a disease in a given population.

Mucosal membrane

The thin lining that borders body cavities that are exposed to the external environment.

Mutate

Undergo changes in the genetic makeup.

Pandemic

An outbreak of infectious disease that has spread through human populations across a large geographical region.

Pathogens

Disease causing microbes.

Peristalsis

Relaxation and contraction of muscles in the small intestine that propels food through the digestive tract.

Placenta

An organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply.

Route of transmission

The path that a microbe takes to travel from an infected host to an uninfected one.

Strains

Genetic variants of the same organism or species

Transmission

The passing of a communicable disease from an infected host to an uninfected host.

Urethra

The tube that leads from the bladder and discharges urine to the outside of the body.

Vector

Intermediate carrier of a disease

Antiretroviral drugs

Drugs that stop a retrovirus from multiplying.

Asymptomatic

Without symptoms.

Biological warfare

Use of toxins produced by living organisms or whole organisms themselves, usually microbes, as weapons.

Bubonic plague

A severe systemic infection caused by the bacterium Yersinia pestis.

Crimea

A peninsula to the south of Ukraine in the Black Sea.

Endemic

Prevalent in a given geographical area.

Helper T cell

A type of immune cell that calls other immune cells to come and fight an infection.

Inoculate

To introduce a microbe into a suitable situation for growth, such as into a human host.

Latent

Dormant or inactive disease, and in this case non-dividing bacteria.

Morbidity

Illness, loss of function and disability

Quinine

An antimalarial drug derived from the Cinchona tree. It is usually taken orally, but if the patient is very sick, it is administered intravenously.

Retrovirus

A virus that incorporates its genome into the host cell's DNA.

Sputum

Mucus coughed up from the lower airways.

Tuberculin skin test

A test for whether a person has been exposed to the tuberculosis bacterium.

Virulence

A pathogen's ability to infect and cause sickness.

WHO

An agency of the United Nations which oversees international public health issues.

Antibiotics

Molecules, produced usually by bacteria and fungi, which have the ability to suppress the growth of microbes or kill them.

Antigen

A structure which can be recognized by the immune system as foreign.

Bacilli

Rod-like bacteria.

Botulism

Illness that results from toxins produced by the bacterium Clostridium botulinum.

Capsule

An external layer made of sugars that surrounds some bacteria.

Cell wall

An external layer surrounding the plasma membrane of most bacteria.

Chemotaxis

The targeted movement of an organism towards or away from a stimulus.

Cocci

Sphere-shaped bacteria

Colonize

Ability of bacteria to adapt to permanently inhabit our bodies.

Enzymes

Proteins produced by living organisms that are used to speed up chemical reactions.

Gonoccoci

Gram-negative bacteria which cause gonorrhea.

Gonorrhea

Sexually transmitted disease caused by gonoccoci, also called Neisseria gonorrhoeae.

Lipopolysaccharides (LPS)

Large molecules composed of lipids and polysaccharides, critical in the making of the Gram-negative outer membrane.

Lipoteichoic acid (LTA)

A polymer of modified lipids used to strengthen the Grampositive cell wall.

Meningitis

Inflammation of the membranes covering the brain and the spinal cord.

Murein (peptidoglycan)

A complex molecule (polymer) made of sugars and amino acids, which is the building block of the bacterial cell wall

Peptides

Small proteins made of a few amino acids.

Plasma (cell) membrane

A membrane that separates the internal cell contents from the outside environment.

Pneumonia

Inflammation of the lung caused by microbes.

Tetanus

An infection caused by Clostridium tetani characterized by muscle spasms due to toxins produced by the bacteria.

Toxins

Molecules (usually proteins) produced by bacteria that are toxic to the host's cells, and a major reason for the symptoms of an infectious disease.

Transport channels

Protein complexes in the cell membrane used to transport ions and molecules across the membrane.

Turgor pressure

The pressure caused by the plasma membrane on the cell wall as the result of water flowing from a dilute outside environment into more concentrated internal cell content

Budding

The process in which viruses leave the host cells by budding off its surface by wrapping their capsids in the host cell membrane.

Capsid

Protein shell of a virus surrounding and protecting its genome. Complex Viruses that have a capsid that is not icosahedral nor helical and may have additional structures.

Cytoplasm

The internal content of a cell, excluding the nucleus when present.

Endocytosis

The process which cells use to absorb molecules from the outside by engulfing and bringing them inside the cytoplasm.

Endosome

A membrane bound vesicle in eukaryotic cells used to transport molecules within the cytoplasm. These molecules can be engulfed from outside or produced inside the cell.

Envelope

Membrane layer surrounding the capsid that is derived from the host cell membrane.

Eukaryotes

Organisms that contain a membrane bound nucleus and organelles.

Extracellular

Outside of the cell.

Genome

The genetic material of an organism.

H1N1

A strain (type) of the flu virus.

Helical

Having the shape of a spiral or a helix.

Hemagglutinin

A protein on the surface of flu viruses which is used as a receptor to bind to host cells.

Icosahedral shape

Having the shape of an icosahedron that has 20 identical triangular faces.

Lysis

The process of rupturing or breaking down of a cell.

Micron (micrometer, µm)

One millionth of a meter

Prokaryotes

Organisms that lack a nucleus or other membrane-bound organelles.

Receptor

A molecule in or on a cell that receives chemical signals.

Sialic acid

A modified sugar molecule present on the surface of many cells and used as a receptor by the flu virus.

Tropism

The property of a specific virus to attach to only a specific type of cells.

Uncoating

The process of release of the viral genome.

Virion

One viral particle that contains all the components of a mature virus.

Viruses

Small, non-cellular (lacking a cell), infectious agents that can replicate only within the cells of living organisms

Antibodies

Proteins produced by the immune system that bind to and eliminate foreign bodies.

Bone marrow

The soft tissues inside the bones, producing our blood cells.

Cilia

Hair-like organelles that are found on the surface of some eukaryotic cells. In the trachea, they help brush up mucus and dust particles away from the lungs.

Colonization

The process of bacteria adapting to permanently inhabit our bodies.

Commensal flora

The microbes that normally inhabit our bodies and coexist with us without causing disease.

Commensal microbes (flora)

The microbes that normally reside within a host.

Commensalism

Symbiotic relationship in which one organism derives a benefit, and the other is unharmed.

Complement system

Proteins produced by the body that are toxic to microbes.

Defensins

Small peptides, which can poke holes microbial cell membrane causing them to die.

Keratin

Protein that is one of the key components of skin, nails, and hair

Lysozyme

An enzyme found on skin or in saliva that can degrade the cell walls of Gram-positive bacteria.

Peritoneal cavity

Space between the organs in the abdominal cavity and the abdominal wall.

Phagocyte

Scavenger cell that engulfs and samples foreign bodies.

Phagocytosis

The process of engulfing of solid particles by a phagocyte.

Sterile

Free of any biological agents including microscopic ones such as bacteria, fungi and viruses.

Thymus

Soft organ behind the breastbone where T cells mature (develop) to respond to pathogens.