3M Flashcards
a disease that can be spread from one person to the other.
Communicable disease
a non-infectious disease that cannot be spread, lifestyle related
Non-communicable disease
disease
pathos
microbe that can cause a disease
Pathogen
study of structural and functional manifestations of the disease
Pathology
the ability of the pathogen to cause a disease
Pathogenicity
mechanism s involved in the development of a disease
Pathogenesis
colonization by a pathogen
Infection
o the virulence of the pathogen
o how the pathogen that enters the body
o number of organisms that enter the host
AGENT
person’s health and nutritional status
HOST
o Physical factors such as heat, location, etc.
o Availability of appropriate reservoirs, hosts, vectors
o Sanitary and housing and water supply
ENVIRONMENTAL FACTORS
EPIDEMIOLOGIC TRIAD
AGENT
HOST
ENVIRONMENTAL FACTORS
CHAIN OF INFECTION
pathogen
source of the pathogen/reservoir
portal of exit
mode of transmission
portal of entry
susceptible host
4 PHASES IN THE COURSE OF AN INFECTIOUS DISEASE
INCUBATION PERIOD
PRODROMAL PERIOD
PERIOD OF ILLNESS
CONVALESCENT PERIOD
time between the arrival of the pathogen and the onset of symptoms
INCUBATION PERIOD
person feels out sorts but doesn’t experience actual symptoms; person feels like coming down with something but is unsure about it
PRODROMAL PERIOD
person experiences typical symptoms associated with that particular disease; This is where communicable diseases are easily transmitted
PERIOD OF ILLNESS
patient recovers or may have permanent damage from the destruction of tissues
CONVALESCENT PERIOD
infections located in one organ or organ system
LOCALIZED INFECTION
infection that involves 2 or m ore organ system
GENERALIZED / SYSTEMIC INFECTION
known to have a rapid onset and recovery
ACUTE INFECTION
infection with a slow onset and
prolonged duration; i.e. leprosy
CHRONIC INFECTION
in between; i.e. bacterial endocarditis
SUBACUTE INFECTION
o experience perceived by the patient only
o subjective manifestation meaning only the patient can tell and express the presence and degree of severity of a manifestation
SYMPTOMS
objective evidence of a disease
SIGN
infectious disease that may go from symptomatic to asymptomatic, then sometime later go back to symptomatic
LATENT INFECTIONS
infectious disease caused by one pathogen
PRIMARY INFECTION
an infection that superimposes the primary infection but caused by a different pathogen
SECONDARY INFECTION
STEPS IN THE PATHOGENESIS OF INFECTIOUS DISEASE
Entry of pathogen
Attachment of pathogen to some tissues Multiplication of pathogen resulting in localized infection
Spread of pathogen to neighboring tissues or to the bloodstream
Evasion of host defenses
Damage to host tissues
VIRULENCE FACTORS
ATTACHMENT
OBLIGATE INTRACELLULAR PATHOGENS
FACULTATIVE INTRACELLULAR PATHOGENS
CAPSULE
FLAGELLA
EXOENZYMES
TOXINS
some pathogens must anchor or attach them selves to target cell right after they have gained access to the body
ATTACHMENT
some bacteria must live within host cells to survive and multiply. These pathogens can quickly adapt to an intracellular environment
OBLIGATE INTRACELLULAR PATHOGENS
Pathogens that can live both within and outside host cells. It is considered a virulence factor because these pathogens can reside practically anywhere
FACULTATIVE INTRACELLULAR PATHOGENS
enables the flagellated (motile) bacteria to invade aqueous areas of the body, thus it also enables the bacteria to avoid phagocytosis since it’s more difficult for phagocytes to catch a moving target
FLAGELLA
enzymes produced by pathogens that enable them to evade host defense mechanisms, invade, or cause damage to body tissues
EXOENZYMES
exoenzymes that destroy tissues
Necrotizing Enzymes (proteases and lipases
▪ causes clotting by conversion of fibrinogen
to fibrin
▪ enable the pathogen to clot plasma and
thereby to form a sticky coat of fibrin around
themselves for protection from phagocytes
Coagulase
▪ have the opposite effect of coagulase
▪ pathogens that produce kinases are able to escape from clots. It is necessary for them because normally, the host will cause a fibrin clot to form around pathogens in an attempt to wall them off and prevent them from invading deeper. If they are able to escape the clot, they will not be trapped and can certainly move away from the pathogen
Kinases / Fibrinolysins
▪ also called as “spreading factor”
because they dissolve hyaluronic acid and collagen enabling pathogens to invade deeper into tissues
▪ Hyaluronic acid and collagen are important structures in the tissues and blood vessels
Hyaluronidase
Enzymes that cause damage to the
host’s red blood cells and also provides the pathogens with a source of iron
Hemolysins
breaks down phospholipids that are
collectively referred to as lecithin. They
are destructive to cell m em branes because the membranes are made up if phospholipid bilayer
Lecithinase
breaks down collagen, produced by Clostridium perfringens
Collagenase
▪ parts of the cell walls of Gram-negative bacteria
▪ can cause serious, adverse, physiologic effects such as fever and shock. Shock is a life-threatening condition resulting from very low blood pressure and an inadequate blood supply to body tissues and organs
Endotoxins
▪ toxins that are produced within cells
and then released from the cells;
Exotoxins
▪ affects the Central Nervous System
▪ Produced by Clostridium botulinum
Neurotoxins
▪ affect the gastrointestinal tract, often
causing diarrhea and sometimes
vomiting
▪ Vibrio cholerae – CHOLERA, Bacillus
cereus – FOOD POISONING in IMPROPERLY COOKED FOOD, Salmonella sp. – ACUTE GASTROENTERITIS Shigella - DYSENTERY
Enterotoxins
▪ causes the epidermal layers of skin to slough
away
▪ Staphylococcus aureus – Staphylococcal
Scalded Skin Syndrome
Exfoliative toxin
Produced by Streptococcus pyogenes –
SCARLET FEVER
ERYTHROGENIC TOXIN
kills WBCS, Staphylococcus aureus
LEUKOCIDIN
produced by Corynebacterium diphteriae
DIPHTHERIA TOXIN
Pathogens are able to periodically change their surface antigens
ANTIGENIC VARIATION
Pathogens conceal their foreign nature by coating them selves with host proteins
CAMOUFLAGE
Pathogen’s surface antigens closely resemble host antigens and are therefore not recognized as being foreign
MOLECULAR MIMICRY
