Infection, Infectious Diseases, and Epidemiology Flashcards
Other names for normal microbiota?
normal flora or indigenous microbiota
What is normal microbiota?
Organisms that colonize the body’s surfaces without normally causing disease
What microbiota remain in a person for life?
Resident microbiota
What microbiota remain in the body for a few hours, days, or months?
Transient microbiota
What does axenic mean?
free of any microbes (never colonized by normal flora)
When does the acquisition of normal microbiota begin?
During the birthing process and first few months of life
Define opportunistic pathogen
Normal microbiota that cause disease under certain circumstances
What are the 3 ways normal microbiota can become opportunistic pathogens?
Introduction into unusual site (E. Coli in urethra), immune suppresion (AIDS/cancer), and changes in the normal microbiota (antibiotics)
What is a site where pathogens live until they can infect a new host?
A reservoir of infection
What are the 3 types of reservoirs of infection?
Animal reservoirs
Human carriers
Non-living reservoirs
Diseases naturally spread from animal hosts to humans?
Zoonoses
7 common zoonoses
Malaria Toxoplasmosis Anthrax Bubonic Plague Lyme Disease Rabies Yellow Fever
Characteristics of human carriers
- asymptomatic but infective to others
- may have defense systems that protect them
What are the 2 strategies to limit the spread of disease?
Isolation and quarantine
Separation of ill people who have a communicable disease is called..
Isolation
Separation and restriction of movement of well persons who may have been exposed to a communicable disease is called..
Quarantine
What are 3 examples of nonliving reservoirs? and how are they exposed to microbes?
soil, water, and food
- contaminated by feces or urine
2 ways to be exposed to microbes
contamination or infection
The mere presence of microbes in or on the body?
contamination
When organism evades body’s external defenses, multiplies, and becomes established in the body?
Infection (MAY OR MAY NOT RESULT IN DISEASE)
What are the 3 (4) major portals/pathways in which pathogens enter the body?
Skin
Mucous membranes
Placenta
(parenteral route - puncture wound)
Skin portals of entry (3)
- openings/cuts
- hair follicles/sweat glands
- burrowing into/digesting outer layers of skin
What is the MC site of entry for pathogens?
respiratory tract
4 categories of pathogens that cross the placenta
Protozoan
Bacteria
DNA Viruses
RNA Viruses
Protozoan pathogen that crosses placenta
toxoplasma gondii
Bacterial pathogens that cross the placenta
treponema pallidum and listeria monocytogenes
DNA viruses that cross the placenta
cytomegalovirus and parvovirus B19
RNA viruses that cross the placenta
lentivirus (HIV) and Rubivirus
Infection
The invasion of the host by a pathogen
Disease
Results if the invading pathogen alters normal body functions (aka morbidity)
Pathogenicity
Abilityof a microorganism to cause disease
Virulence
Degree of pathogenicity (how easy is it for the organism to cause disease)
Antigenicity
The ability of a substance to stimulate the production of antibodies or cell-mediated immune responses
Symptoms
Subjective characteristics of disease felt only by the patient (Ex: headache & nausea)
Signs
Objective manifestations of disease observed or measured by others. (ex: fever, vomiting, swelling, and redness)
Syndrome
Group of symptoms and signs that characterize a disease or abnormal condition
-osis
condition of -
patho
abnormal
septi-
rotting
terato-
defects
3 components of the triad of health
agent, host, environment (in balance = health, Out = disease)
What has the ability to make attachment proteins and attach bacteria together to form a biofilm
An adhesion factor
What are secreted by pathogens that dissolve structural chemicals in the body and help the pathogen maintain infection, invade, and avoid the body defenses
Extracellular enzymes
What is the MC biofilm?
dental plaque
What are chemicals that harm tissues or trigger host immune responses that cause damage?
Toxins
2 types of toxins? examples
exo- & endo- (cytotoxins and lipid A respectively)
What prevents phagocytosis by the host’s phagocytic cells, is a bacterial capsule, and makes the pathogen not be recognized as foreign
Antiphagocytic Factors
5 stages of infectious disease
Incubation Prodromal Illness Decline Convalescence
The time between infection and first symptoms or signs
Incubation period
A short period of generalized, mild symptoms
Prodromal period
The most severe stage, signs/symptoms most evident
Illness
The immune response/treatment vanquish pathogens, body slowly returns to normal
Decline
The patient recovers from illness, tissues repaired and returned to normal
Convalescence
direct, indirect, or droplet (mode of transmission)
contact transmission
airborne, waterborne, foodborne, fecal-oral, bodily fluids (mode of transmission)
vehicle transmission
arachnid or insect, biological or mechanical (mode of transmission)
vector transmission
mom to baby (mode of transmission)
perinatal transmission
Animals that carry pathogens (general)
Arthropods
Vector that only carries the pathogen
mechanical vector
Vector that serves as host for pathogen
biological vector
2 classes of arthropods
Arachnids & Insects
Types of arachnids
ticks & mites
Types of insects
fleas, lice, flies, mosquitos, and true bugs
Most important arachnid vector?
tick
Most important insect vector?
mosquitos
MC and most important vector?
mosquitos
Number of new cases of a disease in a given area during a given period of time
Incidence
Number of total cases of a disease in a given area during a given period of time
Prevelance
A disease that normally occurs at regular intervals at a relatively stable incidence within a given population or geographical area
Endemic
Only a few scattered caseswithin an area or population
Sporadic
Occurs at a greater frequency than is usualfor an area or population
Epidemic
An epidemic that occurs simultaneously on more than one continen
Pandemic
Careful tabulation of data concerning a disease. Try to identify the index case
Descriptive Epidemiology
Infections acquired in health-care settings (patients or employees)
Nosocomial Infections
Pathogen acquired from the HC environment
Exogenous
Pathogen arises from normal microbiota due to factors In the HC setting
Endogenous
Results from modern medical procedures
Latrogenic
What is the most effective way to reduce nosocomial infections?
Hand washing bitches
