Week 5 Microorganisms & Disease Flashcards
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
infection
the act of introducing pathogens or infectious material into or on an inanimate object
contamination
an organism that due to its own virulence is able to produce disease
true pathogen
an organism that exists as part of the normal flora but may become pathogenic under certain conditions
opportunist
the state of producing or being able to produce pathological changes and disease
pathogenicity
relative power of an organism to produce disease
virulence
dilution or weakening of the virulence of a microorganism; reducing or abolishing pathogenicity
attenuation
the microbial population that lives with the host in a healthy condition
normal flora
resistant, as in bacteria, to the action of a drug or drugs
drug-fast
chain of infection
-Causative agent exists in a reservoir
-Causative agent exits the reservoir and is transmitted to a new host through a portal of entry
-New host may become ill if certain conditions are met
factors that influence virulence
-Virulence of the organisms
-Portal of entry and exit
-Number of organisms present
-Resistance of the host
a form of infection caused by a pathogen or agent not normally present in the body
exogenous infection
organism disorder caused by an infectious agent already present in the body
endogenous infection
the first infection that a host has after a period of health from which a second infection develops
primary infection
infection caused by a different organism than the one causing the primary infection
secondary infection
infection caused by two or more organisms
mixed infection
a disease with a rapid onset and short duration
acute
a disease with a slow onset and long duration
chronic
infection (usually acute) occurring at the end of a disease usually resulting in death
terminal
a disease that may be transmitted directly or indirectly from one individual to another
communicable
a disease that occurs continuously in a particular region
endemic
a disease that is currently in higher than normal numbers in a given community
epidemic
an epidemic that has become very widespread or is worldwide
pandemic
a disease which occurs occasionally in a random or isolated manner
sporadic
diseases that do not spread from person to person
non-communicable
an infection confined to one area of the body
local
an infection that involves the whole body
general (systemic)
an infection in which the organisms are originally confined to one area but enter the blood or lymph vessels and spread to other parts of the body
focal
the presence of bacteria in the blood
bacteremia
condition characterized by the multiplication of bacteria in the blood
septicemia
the presence of toxins in the blood
toxemia
poisonous substances of plant, animal, bacterial, or fungal origin
toxins
a bacterial toxin produced within a living cell and secreted into its surrounding medium
exotoxin
a bacterial toxin that is liberated only when the cell producing it disintegrates (found only in gram negative bacteria)
endotoxin
a coating that surrounds some bacterial cells; a loose gel-like structure that, in pathogenic bacteria, helps to protect against phagocytosis (immune response) or other environmental extremes
capsule
a thick-walled body produced by a bacterium to enable it to survive unfavorable environmental conditions; allows organisms to assume a “dormant” form
endospore
proteins that act as biological catalysts; some microorganisms can produce those that damage human tissues
enzymes
Three main sources of infection or broad reservoirs
-Animals or persons ill of the infection
-Chronic animal or human carriers
-The environment
Types of direct transmission (5)
Physical contact
Droplet infection (aerosol) – respiratory droplets
Sexual transmission
Congenital –from mother to fetus
Blood-to-blood contact
Types of indirect transmission
Food
Water
Air
Milk
Fomites (any inanimate object that harbors a disease agent and may serve to transmit it)
Soil
Zoonoses
a carrier that transmits the causative organism of a disease from infected to noninfected individuals
vector
an arthropod vector in which the disease-causing organism multiplies or develops within the arthropod prior to becoming infective
biological vector
a living organism capable of transmitting infections by carrying the disease agent on its external body parts or surfaces
mechanical vector
portals of entry and exit (5)
skin & mucous membranes
respiratory tract
digestive tract
genitourinary tract
placenta
mechanical defenses (8)
Skin (epithelium)
Mucous membranes
Normal microbiota of the skin
Oils in the skin produced by the sebaceous glands
Necrobiosis
Tears
Ciliated epithelium in the respiratory tract
Flushing of urine
process by which the epithelial layer of skin sloughs off and is replaced
necrobiosis
Physiological defenses (3)
Inflammation
Fever
Phagocytosis
a tissue reaction to irritation, infection, or injury marked by localized heat, swelling, redness, pain, and sometimes loss of function
inflammation
a process in which phagocytes engulf and destroy microorganisms, other foreign antigens, and cell debris
phagocytosis
chemical defenses (5)
Body secretions
Lysozyme
Gastric juices (pH levels and hydrochloric acid)
Antibodies (immunoglobulin)
Interferons
an enzyme that uses water to break down the peptidoglycan layer in prokaryotic pathogens
lysozyme
glycoprotein substances developed by the body in response to, and interacting specifically with, an antigen
antibodies (immunoglobulins)
proteins that respond to viruses to inhibit spread of pathogenic organisms
interferons
