Chapter 24-Microbe Virulence and Human Resistance

coagulase

A bacterial enzyme that causes blood plasma to clot

phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

ID50

infectious dose: number of microbes required to produce infection in 50% of population

types of immunity

innate and adaptive

LD50

lethal dose: amount of toxin or pathogen necessary to kill 50% of the population in a particular time frame

tears

mechanical barrier of eyes

droplet transmission

microbes are spread in mucous droplets that travel short distances

reservior

natural habitat of a disease causing organism

noncommunicable diseaes

not spread from one person to another

secondary infection

opportunistic infection after a primary (predisposing) infection

pathogen

organism capable of producing diease

host

organism from which a parasite obtains its nourishment

focal infection

organisms are originally confined to one area but enter the blood or lymph vessels and spread to other parts of the body

cytomegalovirus

pathogen that can cross the placenta

direct contact transmission

person-to-person transmission, no intermediate object is involved

3 mechanisms of direct transmission

physical contact, droplet infection and congenital transmission

googles or face shield

place over face and eyes and adjust to fit

toxemia

presence of toxins in the blood

viremia

presence of viruses in the blood

bactermia

presense of bacteria in the blood

resistance

relative ability of the body to defend itself against infection

virulence

relative power and degree of pathogenicity possessed by organisms to produce disease

mask or respirator

secure ties at middle of head and neck, fit band to nose bridge, fit snugly to face and below chin, fit-check respirator

general infection

systemic infection

pathogenicity

the ability of a microorganism to survive and cause infection in a host

resistance

the ability of the human to defend against a pathogen

necrobiosis

the process by which the epithelial layer of skin sloughs off and is replaced with new cellscontinuously dies

natural active immunity

the result of developing a disease and recovering from it, body produces antibodies

artificial passive immunity

the result of injection of pre-made antibodies in the form of convalescent serum

infection

the state or condition in which the body, or a part of it, is invaded by a pathogenic agent that under favorable conditions, multiplies and produces injurious effects

mechanical vector

transports the infectious agent without being infected

olgoadenylate synthetase

type of antiviral protein (AVP)

gloves

extend to cover wrist of isolation gown

hyaluronidase

hydrolyzes hyaluronic acid, breaks down connective tissue, promotes spread of disease

2 modes of disease transmission

indirect and direct

exogenous infections

infections caused by organisms not present in the body

endogenous infections

infections causes by bacteria that are normally nonpathogenic and normally inhabit that digestive tract

phagolysosome

Intracellular vesicle formed by fusion of a phagosome with a lysosome, in which the phagocytosed material is broken down by degradative lysosomal enzymes.

antigen

a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies.

exotoxin

a toxin, generally a protein, produced by a microorganism and excreted into its surrounding medium

biological vector

actively participates in a pathogen's life cycle

primary infection

acute infection that causes the intital illness

indirect contact transmission

agent is transferred via a nonliving object

fomites

any inanimate objects to which infectious material adheres and can be transmitted

septicemia

bacteria or its products are present in the blood

endotoxin

bacterial toxin that is confined within the body of a bacterium that is released only when actively dividing or being broken down

body secretions

body line of chemical defense against diseases

sepsis

body's immune response to the presence of bacteria or its products in the blood

mixed infection

caused by 2 or more organisms

local infection

caused by microorganisms lodging and multiplying at one point in a tissue and remaining in that tissue

indirect forms of transmission

food, milk, fomites, water, soil, biological and mechanical vectors

gown

fully cover torso from neck to knees, arms t end of wrists, and wrap around the back

pandemic diseaes

diseases that affect the majority of the population of a large region, or are epidemic at the same time in many parts of the world

epidemic diseases

diseases that attack many people at the same time in the same geographic region

communicable disease

diseases that may be transmitted directly or indirectly from one individual to another

endemic disease

diseases that occur continuously in a particular region but usually have low mortality

sporadic diseases

diseases that occur occasionally or in scattered instances within a geographic region

antibodies

Glycoproteins that attach to antigens, keeping them from harming the body

interferon

Protein produced by cells in response to being infected by a virus; helps other cells resist the virus.

fibrinolysin

enzyme that breaks down the fibrin meshwork that stabilizes blood clots; also referred to as plasmin

phagocyte

a cell that ingests and destroys (digests) foreign matter or microorganisms, produced in bone marrow

lysozyme

a chemical enzyme that is found in tears and saliva that uses water to break down the peptidoglycan layer in prokaryotic pathogens

vectors

a live animal that transmits an infectious agent from one host to another

inflammation

a localized response to an injury or to the destruction of tissues

causative agent

a pathogenic microorganism that causes disease

fever

a physiological defense mechanism where WBC release chemicals that increase the body's internal temperature