Chapter 13 Infection & Disease Flashcards
infection
pathogenic m.o. penetrate host’s defenses and multiply
Infectious disease
Disruption of a tissue/organ caused by microbes or their products
normal microbiota
“normal flora”
m.o. normally present in and on body
Benefits of normal flora
Provide nutrients to host (vitamins)
Can break down food for host
Immune stimulation
Sterile body organs
Heart and circulatory system, liver, kidneys and bladder, brain and spinal cord, muscles, bone, ovaries/testes, glands, internal eye, sinuses, middle and inner ear.
Opportunistic pathogen
Causes disease in immunodeficient people w/another primary disease
Virulence factors
Microbial components that contribute to ability to cause disease in a susceptible host
The 4 portals of entry for microbes
Skin: abrasions, cuts, punctures
GIT: pathogens in food and drink
Respiratory: air spit
Urogenital: STDs, mucosa, unbroken skin
Pathogens during pregnancy and birth
cross placenta or during birth.
Toxoplasmosis Other Rubella Cytomegalovirus Herpes
Exotoxins
Secreted by living cell and targets specific tissues
ex Clostridium botulism
Endotoxins
Outer layer/LPS of gram- m.o. that causes fever, shock, vasodilation, diarrhea, and death
Systemic infection
Affecting the entire body
Focal infection
Localized infection
Mixed infection
Infection on viruses and bacteria
Acute infection
Short-lived infection
Symptoms
Subjective evidence of disease as sensed by the patient
ex feeling unwell
Signs
Objective evidence of disease as noted by an observer
Incubation
Time of initial contact with m.o. to first symptoms
Prodromal stage
Time of vague symptoms
ex general fatigue
Period of invasion
Active infection with obvious signs of disease
Convalescent period
Recovery period, signs of disease subsiding
Leukocytosis
excess WBC
Leukopenia
lack of WBC
Bacteremia/Viremia/Septicemia
m.o. present in the blood
Exit portals for m.o.
Respiratory & salivary products
Skin scales
Fecal/Urogenital
Bleeding/removal of blood
Latency
dormant state, can become active again
ex mono, herpes
Reservoir
primary habitat from which a m.o. originates
Carrier
individual who is asymptomatic and spreads pathogen to others
Biological vector
Actively participates in a pathogens life cycle
ex ticks, mosquitos
Mechanical vector
Transports the infectious agent w/o being infected
Zoonosis
infection indigenous to animals but is transmissible to humans
Vertical Transmission
Transmission of disease from mother to child from pregnancy, birth, breastfeeding
Horizontal transmission
Transmission of disease from members of the same species that are not mother/child
Contact transmission
Horizontal and vertical transmission, biologic vector
Indirect transmission
Aerosols, fecal oral, food, fomites
Fomites
Toys, doorknobs, towels, soaps
Universal precautions
Assume all patient specimens could harbor m.o.
Handwashing, gloves, masks
Body substance isolation techniques
Etiology
Study of causation, origination
Epidemic
sudden acute disease outbreak
Pandemic
Worldwide epidemic
Endemic
Chronic occurrence in a specific location
Epidemiology
Study of occurrence of disease
Point source outbreak
Single source, occurring one time, potluck
Propagated epidemic
sharp rise in cases as individuals pass disease to others
Herd health view
High level of general health in the pop. will help all in community
Mortality rate
Deaths by illness
Morbidity rate
Illnesses by disease
Sporadic
Random, small outbreaks
