Micro/Immuno 1 Flashcards
Microbiology
the study of microorganisms (microscopic organisms = smaller than 1 mm. in diam.) (prions, viruses, bacteria, protozoa, certain fungi, certain algae, helminthes?)
Clinical microbiology
study of those microorganisms (pathogens or pathogenic microorganisms) that cause diseases (infectious disease) in humans and domestic animals.
Parasitology
(historically) study of diseases due to protozoa and helminthes (parasites).
Immunology
the study of the body’s defenses to pathogens, foreign substances, cancer cells.
Health
a state of relative equilibrium in which body’s organ systems function adequately or properly (without evidence of disease or abnormality)
Disease
any change from state of health or equilibrium
\ an abnormal state in which part or all of body not properly adjusted or is not capable of carrying out normal functions
\ a change in the normal physiology of the body condition of an organ, part, structure or system of body in which there is incorrect functioning due to the effect of heredity, infection, diet, or environment
\ (MIMS) = when and infection has detectable clinical consequences, severe or mild
Pathology
the study of diseases (branch of biol. or medicine)
\ (pathos = latin for suffering)
Etiology
the cause of a disease (ie, infectious disease = microbes)
\ Koch’s postulate (or variation of ) used to prove specific etiology
Pathogenesis
manner in which (how) a disease develops
\factors involved in development of disease
Infectious disease
a physiologically impaired state of a plant or animal resulting from microbial infection, microbial products (i.e., toxins), or microbial
activities (disease caused by a microorganism)
What do Koch’s postutlates to prove?
a) Pathogen must be present en every case of disease
b) Pathogen must be isolated from diseased host and grown in pure culture
c) Disease must be reproduced when pure culture introduce into non-diseased susceptible host
d) Pathogen must be recovered from this experimentally infected host.
Pathogenic microorganisms (pathogens)
those microorganisms(viruses, bacteria, fungi) that can cause disease (in humans, animals, plants, etc)
Strict pathogen
Always associated with the disease
Opportunistic pathogen
only under certain conditions (i.e., immunocompromised individuals
Parasites
Those protozoans and helminthes that can cause disease
Pathogenicity
organisms ability to cause disease
Virulence
the degree of pathogenicity
Infection
invasion and colonization of body by pathogens with subsequent growth/proliferation in/on our bodies (not synonymous with disease)
\ (MIMS = presence of pathogen in individual of pop, not necessarily disease)
\ doesn’t always cause disease can include commensalism)
Communicable disease
any disease that can spread from one host to
another, either directly or indirectly (ie, chickenpox, measles, typhoid fever)
\ MIMS aka infectious
Contagious disease
a disease that is easily spread from one person to another(ie, chickenpox, measles) aka infectious
Noncommunicable disease
a disease that can’t be spread from one host to another
Signs
objective = objective changes in body that physician can observe and measure (ie, resence of lesions, swelling, fever, paralysis)
Symptoms
subjective = changes in body function (ie, pain, malaise, loss of appetite)
\ these subjective changes not apparent to observor;
Syndrome
specific group of symptoms and/or signs that always accompanies a particular disease (characterisitic of particular disease)
Localized infection
one where the invading pathogen is limited to a relatively small area of body (ie, boils and abscesses)
Sytemic (generalized) infection
infection where microorganisms or their
products are spread throughout body by circulation or lymphatic system (ie, measles)
Bacteremia
presence of bacteria in blood
Septicemia
when bacteria actually multiply in blood (blood infection)
Toxemia
presence of toxins in blood
Viremia
presence of viruses in blood
Subclinical infection
inapparent infection - one that doesn’t cause any noticeable illnes (ie, poliovirus can be carried by people who never develop polio)
Acute disease
one that develops rapidly but only lasts a short time (ie, influenza)
Chronic disease
disease that develops more slowly, body’s reaction less severe, but can last for long time period (ie, leprosy, TB)
Latent disease
one in which causative agent remains inactive for a time and then becomes active and produces symptoms of the disease (ie, shingles due to varicella-zoster virus)
Predisposing factor
a factor that makes body more susceptible to a disease and may alter the course of a disease (ie, sometimes gender, age, genetics, climate,
weather, inadequate nutrition, etc)
Epidemiology
study of when and where disease occurs and how they are Xmitted
Germ theory of disease
(1870s) (Robt. Koch) - certain diseases due to specific microbes- (1st was anthrax (1876); 2nd TB (1882))
Koch’s postulates
series of steps to prove causality between specific microorganism and specific disease (best for cellular microbes, esp bact)
Development of disease
once pathogen overcomes defenses, development of disease follows a certain sequence of steps
Period of incubation
time interval between initial infection and first
appearance of any signs or symptoms of disease (asymptomatic)
\ for some diseases constant; for others it varies
\ microbe has invaded host and is migrating to various tissues but has not yet increased to sufficient numbers to cause discomfort or infectivity
Prodromal period
relatively short period that follows incubation period in some diseases
\ characterized by early, mild symptoms of disease (ie, mild aches and malaise)
\ symptoms not usually precise enough for diagnosis
\ but patient contagious cause enough mult of microbe
Period of illness
clinical stage = time when disease most acute
\ person experiences overt signs and symptoms of disease (fevers, chills, muscle pain (myalgia), sore throat, lymph node enlargement (lymphadenopathy), etc.
\ either persons immune response and other defenses overcome pathogen and person recovers, or patient may die
\ person is contagious
Period of decline
time when signs and symptoms decline (fever
subsides, etc) - first signs of recovery
\ usually no longer contagious; but can be a carrier
Period of convalescence
person regains strength, and body returns to its prediseased state (= recovery)
Latent period
time between initial infection and infectiousness
Pathogenesis
the progression of a disease state
Virulence factors
anything that contributes to pathogens
Virulence (i.e., capsule, adhesion molecule)
\ virulence due to: adhesion, cell penetration, antiphagocytic activs,
toxin produce, interaction with immune system
\ due to many microbial genes
\ mutations produce new prots and traits, and plasmid acquisition
Epidemiology
study of occurrence (ie, source, who gets diseaes), spread and control and prevention of diseases within the human population (attempts at control and prevention of diseases= Public Health)
(CDC collects data from local agencies -reports (MMWR) and monitors
\ when and where diseases occur and how they xmitted in human pops (patterns of xmission within pop) = study of circumstances under which diseases occur in a population
methodology
study of whole population and generalize from large numbers of individual cases (induction)
\ based on collection of detailed statistical data at several levels
\ie, from purely descriptive, to analytical to experimental (can involve mathematical modeling) - this info can be very useful in combatting/preventing diseases
\ genetic differences between individuals and races
Morbidity rate
incidence of disease in a pop
= # new cases of disease during specific period / # individuals in population
Mortality rate
rate of death in a pop for a disease
= # deaths due to the disease/size of total population with the same disease
Incidence of disease
fraction of population that contracts it during particular period of time
= # new cases arising in population over defined period of time (X # / 100,000 pop in 1
year)
Prevelance of disease
fraction of population having the disease at a specified time (number of cases of infection or disease within the population at given point of time or given period)
Age specific
within an age group
Sporadic disease
disease that occurs only occasionally (typhoid fever in the U.S.)
Endemic disease
disease that is constantly present in population (common cold) \diseases which always present in population at about the same level, usually at low or moderate frequency (ie, chiken pox)
Epidemic disease
when many people in a given area acquire the disease in a relatively short time (ie, influenza) above endemeic levels
= pattern of disease xmission that affects many members of the population within a short period of time (ie, cholera)
Pandemic
epidemic that spreads worldwide (AIDS)\ global epidemics
How many microbes living on your body?
100 trillion
How many cells in your body?
20 trillion
How much of the world’s organisms are microbes?
1/3
Where do most microorganisms exist?
Free-living - in soil and water
Some are symbionts living on or in plants and animals (their hosts)
What is symbiosis?
A close relationship between two or more organisms of two or more different species
What is mutualism?
When both the host and microorganism benefit
What is commensalism?
When the microorganism benefits, but the host is neither harmed nor benefited
What is parasitism?
When the microorganism benefits, but the host is harmed
What is infection?
The growth or colonization by microorganisms (technically, we are all already infected)
When is parasitism most commonly seen?
When we get sick
Do microbes always act as mutualists, commensalists, or parasites?
No, they could be commensal to us but mutualistic to cows, etc.
Why do microbes inhabit hosts?
To reproduce (not just to cause disease)
What is a chemoorganoheterotroph?
Uses organic molecules for energy and carbohydrate source
What is normal microbial flora?
Microbial symbionts of humans
When is the normal flora established?
At birth
Where do the normal flora live?
Inner and outer body surfaces - epidermis upper respiratory tract mouth GI tract vagina distal end of urethra
What percentage of the normal flora live in the large intestine?
90-95%
What are the two groups of normal flora?
Normal resident flora
Transient flora
What are normal resident flora?
Not static, but more or less permanent
What are transient flora?
Temporary (days, weeks, months); changes composition
Are obligate pathogens normal resident or transient flora?
Transient flora
Are most bacteria of the normal flora mutualists, commensalists, or parasites?
Most are commensalists, but overall, the normal flora is beneficial to the human
What is an example of when the normal flora can be beneficial, in terms of pathogens? (3)
- The normal flora attach to our cells, which blocks binding sites where pathogens might try to attach
- They produce bacteriocins, antimicrobial chemicals
- They play a role in the development of the immune system
What is an example of when the normal flora can be negative to the body?
If normal flora move to a different area of the body where they are not supposed to be, like if E. coli move to the urinary tract from the GI tract, causing a UTI
Bacteria in the mouth
Strep. mitis and other streptococci
Trichomonas tenax
Candida
Bacteria in the teeth
Streptococcus mutans Bacteroides Fusobacterium Streptococci Actinomyces
Bacteria in the throat
Strep. viridans Strep. pyogenes Strep. pneumoniae Neisseria spp. Staph. epidermidis Haemophilus influenzae
Bacteria on the skin
Staph. epidermidis
Staph. aureus
Pseudomonas aeruginosa
Bacteria in urethra and vagina
Staph. epidermidis
Diphtheroids
Streptococci
Gram negative rods
Bacteria in nose
Staph. aureus
Staph. epidermidis
diphtheroids
streptococci
Bacteria in the colon
Bacteroides spp. Fusobacterium spp. Strep. faecalis Escherichia coli lactobacillus Staph. aureus Clostridium spp.
What is the term for normal flora that can be pathogenic under certain circumstances?
Opportunistic pathogens
What happens in terms of normal flora when a person uses antibiotics for a long period of time?
The normal flora may be wiped out due to the constant use of antibiotics, making room for fungal infections to take over (which are resistant to the antibiotics)
What is an infectious disease?
a disease due to microbial infection, microbial products (toxins), or microbial elicited body activities (inflammation)
Essentially, a disease caused by a microorganism
What is pathology?
Study of disease; effect on organism’s tissues/organs
What is etiology?
Cause of disease
What is pathogenesis?
Mechanism of disease
What is a strict pathogen?
It causes disease associated with it in most people when present in sufficient dose and transmitted in the correct manner
What is another name for strict pathogen?
Obligate
What is an opportunistic pathogen?
Microorganism that normally does not cause disease except under certain circumstances
What are the four steps from pathogen to disease?
- Signs and symptoms due to
- Damage/dysfunction to tissues/organs/body function due to
- Pathogen’s growth/toxins/bodily processes due to
- The pathogen
What is pathogenicity?
The ability to cause disease; a phenotype of a pathogen
What is virulence?
The degree of pathogenicity
What is the range of degree of virulency?
From avirulent to hyper virulent
What is infection?
Growth and colonization by a microorganism
What is intoxication?
When signs and symptoms primarily or exclusively are due to microbial toxins
Describe the pathogen/host interaction
A race between the pathogen’s ability to multiply, spread, and cause damage or dysfunction, leading to signs and symptoms, and the host’s ability to control and finally eliminate the pathogen
What is the disease threshold?
The minimum number of pathogens or the concentration of toxin which results in sufficient damage or dysfunction to cause disease
What influences the disease threshold?
Type of pathogen Age of host General health of host Genetic background of host Body defenses of host
What does the disease threshold say about someone who is not showing signs and symptoms?
They may be infected, but not with enough concentration of the bacterial toxin to show signs and symptoms
