Exam 3 Vocab Terms

pathology

the study of disease

epidemiology

the study of where and when disease occur

etiology

the study of the cause of a disease

pathogenesis

the development of disease

infection

colonization of the body by pathogens

disease

an abnormal state in which the body is not functioning normally

transient microbiota

microbes that are present for days, weeks, or months

normal microbiota

microbes that permanently colonize the host

symbiosis

the relationship between normal microbiota and the host

commensalism

one organism benefits and the other is unaffected

mutualism

both organisms benefit

parasitism

one organism benefits at the expense of the other

opportunistic pathogens

normal microbiota can take any opportunity and turn against the host

microbial antagonism

competition between microbes

probiotics

live microbes applied to or ingested into the body, intended to exert a beneficial effect

symptom

a change in body function that is felt by a patient as a result of disease

sign

a change in body that can be measured or observed as a a result of disease

syndrome

a specific group of signs and symptoms that accompany a disease

communicable disease

a disease that is spread from one host to another

contagious disease

a disease that is easily spread from one host to another

noncommunicable disease

a disease that is not transmitted from one host to another

incidence

fraction of a population that contracts a disease during a specific time

prevalence

fraction of a population having a specific disease at a given time

endemic disease

disease constantly present in a population

sporadic disease

disease that occurs occasionally in a population

epidemic disease

disease acquired by many hosts in a given area in a short time

pandemic

worldwide epidemic

local infection

pathogens are limited to a small area of the body

systemic infection

an infection throughout the body

focal infection

systemic infection that began as a local infection

sepsis

toxic inflammatory condition arising from the spread of microbes, especially bacteria or their toxins, from a focus of infection

bacteremia

bacteria in the blood

septicemia

growth of bacteria in the blood

toxemia

toxins in the blood

viremia

viruses in the blood

primary infection

acute infection that causes the initial illness

secondary infection

opportunistic infection after a primary (predisposing) infection

incubation period

no signs/symptoms

prodromal period

mild signs/symptoms

illness period

most severe signs/symptoms, spike in number of microbes

decline period

signs/symptoms persist but number of microbes decreases

convalescence period

lingering signs/symptoms, still contagious but returning back to normal

zoonoses

any disease or infection that is transmissible from animals to humans

direct contact transmission

requires close association between infected and susceptible host

indirect contact transmission

spread by fomites (cups, bedding, towels)

droplet contact transmission

transmission via airborne droplets (sneeze, cough, talking)

vehicle transmission

transmission by an inanimate reservoir (food, water, air)

vector transmission

transmission of disease by arthropods

mechanical transmission

arthropod carries pathogen on feet

biological transmission

pathogen reproduces in vector

nosocomial infections

health-care associated infections

pathogenicity

the ability to cause disease

virulence

the extent (severity) of pathogenicity

ID50

infectious dose for 50% of the sample population

LD50

lethal dose (of a toxin) for 50% of the sample population

M protein

component of cell wall that helps resist phagocytosis

Opa protein

component of cell wall that inhibits T helper cells

mycolic acid

component (waxy lipid) of cell wall that resists digestion

coagulase

enzyme that coagulates fibrinogen

kinase

enzyme that digests fibrin clots

hyaluronidase

enzyme that hydrolyzes hyaluronic acid

collagenase

enzyme that hydrolyzes (breaks down) collagen

IgA protease

enzyme that destroys IgA antibodies

antigen

components on the outside of a microbe that stimulated the immune system to make antibodies or sensitized T cells

invasins

protein that rearranges actin filament and allows species to dig deeper into the cell

siderophore

protein that is secreted into medium to steal iron, using the host’s nutrients

toxin

poisonous substance that contributes to pathogenicity 

toxigenicity

ability to produce a toxin

toxemia

presence of toxin in the host’s blood

toxoid

inactivated toxin used in a vaccine

antitoxin

antibodies against a specific toxin

exotoxin

proteins produced inside pathogenic bacteria, which are then released, found in both Gram-negative and Gram-positive bacteria

endotoxin

lipid portion of lipopolysaccharide (LPS), found in the cell walls of Gram-negative bacteria only, and released when bacteria die

leukocidins

toxins that will kill phagocytic leukocytes

hemolysins

toxins that destroy red blood cells

streptolysins

hemolysins produced by Streptococci

superantigens

cause an intense immune response due to release of cytokines from host cells

cytokines

proteins produced by leukocytes, used for communication; directly or indirectly may induce fever, pain, or T cell proliferation

endotoxic shock

a result of high concentration of cytokines made by cells of the immune system

pyrogenic response

the ability of a substance to produce a febrile (fever) response

susceptibility

lack of resistance to a disease

immunity

ability to ward off disease

innate immunity

defenses against any pathogen

adaptive immunity

induced resistance to a specific pathogen

basophil

releases histamines that cause inflammation

eosinophil

kills parasites with oxidative burst

mast cell

kills infected cells (often virus-infected) via cytolysis or apoptosis

neutrophil

phagocytizes bacteria and fungi

monocyte

precursor to macrophage

dendritic cell

phagocytizes bacteria and presents antigens to T cells

natural killer cell

kills cancer cells and virus-infected cells

plasma cell

recognizes antigens and produces antibodies

B cell

recognizes antigens and produces antibodies

T cells

secrete cytokines

first line of defense

• intact skin

• mucous membranes

• normal microbiota

• flushing mechanisms

second line of defense

• phagocytes (neutrophils, eosinophils, macrophages, dendritic cells)

• inflammation

• fever

• antimicrobial substance

third line of defense

• specialized lymphocytes (T cells and B cells)

• antibodies

microbial antagonism/competitive exclusion

normal microbiota compete with pathogens or alter the environment

commensal microbiota

one organism (microbe) benefits and the other (host) is unharmed

hematopoiesis

the production of blood cells and platelets