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What is epidemiology?
Study on when and where disease occur and how transmitted.
What are things to focus on when looking at epidemiological data?
time, number of cases, and population size
Mobidity vs. mortality?
Morbidity is the diseased state, mortality is death.
What is pathology?
The study of disease
What is etiology?
The study of the cause of a disease
What is pathogenesis?
The development of a disease
What is an infection?
Colonization or invasion of the body by pathogens
What is a disease?
State where body isn't functioning normally
The human adult is estimated to have how many human cells? bacterial cells?
How are humans described as a "cylinder"?
Humans are a cylinder with a hole through the center with just about every surface colonized by bacteria
Two examples of sparse areas
stomach and bladder
The stomach was first thought of to be ___________ .
free of orgs
The stomach is usually free of bacteria, but helicobacter pylori survives. How? What does it do?
Not normal flora. Stomach ulcers.
Areas like the bladder can be transiently infected. But what exists to get rid of the intruders?
Normal Clearance Machanisms
What is normal microbiota?
- Permanently colonize the host
- Don't produce disease
What is transient microbiota?
- May be present for days, weeks, or months
What are locations for microbiota on and in the body?
- Nose and throat (upper respiratory system)
- Eyes (conjunctiva)
- Large intestine
- Urinary and reporductive systems (lower urethra in both sexes and vagina in females)
What is mircobial antagonism? Example?
- "Competition" between microbes
- Example = vagine
- Matains pH of 4
- Normal flora inhibits overgrowth of yeast
- if change of pH -> increase growth of yeasts (c. albicans)
- if normal flora is eliminated by: antibiotics, excessive douching, or deodorants -> vaginal infections
What are the consequences of microbial antagonism?
- Normal flora protects host against colonization of potentially pathogenic m/o's
- Complete for nutrients
- Produce substances harmful to invading m/o
- Affect conditions -> pH, O2 availability
What are probiotics?
Live microbes applied to or ingested into the body, intended to insert a beneficial effect
In a population diseases are classified by ______?
Behavior within the host
What is a communicable disease? Directly or indirectly? Examples?
- Disease that spread from one host to another.
- Both directly or indirectly.
- Chicken pox, measles, genital herpes, typhoid fever, tuberculosis
What is a contagious disease? Examples?
- Chicken pox, measles
What is a noncommunicable disease? Example?
- Not spread.
- Caused by m/o inhabiting in the body; may cause disease when introduced into the body.
- Clostridium tetani (tetanus) -> produce disease via abrasions or wounds
What is incidence?
Fraction of a population that contracts a disease during a specific time.
What is prevalence?
- Fraction of a population having a specific disease at a given time.
- Takes in to account both old and new cases.
- How serious and longa disease affects a population.
What are the 4 frequencies of occurance pertaining to disease?
- Sporadic disease
- Endemic disease
- Epidemic disease
- Pandemic disease
What is a sporadic disease?
Disease that occurs occasionally in a population.
What is an endemic disease?
Disease constantly present in a population.
What is an epidemic disease?
Disease acquired by many hosts in a given area in a short time
What is a pandemic disease?
What is herd immunity?
- Immunity in most of a population - does not provide reservoir for organism to hide/evolve/grow.
- Vaccination can provide her immunity.
What is local infection? Example?
- Pathogens are limited to a small area of the body.
- Boils, abscesses
What is a systemic infection? How does it spread?
- An infection throughout the body.
- Spread via the circulatory system.
What is a focal infection?
- Systemic infection that began as a local infection.
- Teeth, tonsils, sinuses
What is bacterium?
Bacteria in the blood.
What is septicemia?
Growth of bacteria in the blood.
What is toxemia?
Toxins in the blood.
What is viremia?
Viruses in the blood.
What is a primary infection?
Acute infection that causes the initial illness.
What is a secondary infection? Example?
- Opportunistic infection after a primary (predisposing) infection.
- Sometimes more dangerous than a primary infection.
- ex. Skin and respiratory tract infecitons
- Pneumocystis pneumonia -> AIDS
- Streptococcal bronchopneuminia -> following influenza
What is a subclinical (inapparent) disease?
- No noticable signs or symptoms.
- Can be carried by people who never develop the illness.
What is a reservoir?
There must be a reservoir of infetion as a source of pathogens for an infectious disease to occur.
What is transmissoion?
- The pathogen must be transmitted to a susceptible host by...
- direct contact
- indirect contact
- or by vectors
What is invasion?
Microorganism enters the host and multiplies.
What is pathogenesis?
- Microorganism injures the host.
- Directly or by toxins
What happens to a vector during mechanical transmission?
Passive transport -> insects feet or other body parts.
What happens to a vector during biological transmission?
Active process -> arthropod bites affected host, pathogen reproduce in vector, transmitted to another host.
What are nosocomial (hospital-acquired) infecitons?
- Acquired as a result of a hospital stay.
- 5-15% all hospital patients acquire nosocomial infections.
- Infections result of human error and misunderstanding of sterile technique.
Bacterial pathogenesis processes include:
- Maintained reservoir
- Transported into host
- Adhere to colonize and/or invade the host
- Multiply in host or host cells (nutrient?)
- Bacterial product secretion and damage
- Shedding and return to environment or reservoir
Reservoir includes _____ , ______, and _____.
humans, animals, and the environment
Animals are a major carrier of bacterial pathogens. True/False?
What are virluence factors?
Any bacterial products that contribute to disease processes, and mutation of these genes result in decrease in infection potential
Invasion includes attacking _______, ________, and ______ and can potentially spread throughout the body
basement membranes, cells, and tissue.
How do microorganisms enter a host to cause disease?
- Adhere to host tissue
- Penetrate or evade host defenses
- Damage host tissues
- Some m/o do not cause disease by direct damaging host tissue
- accumulation of waste products
What are the 3 portals of entry?
3 mucous membranes (portal of entry)
- Respiratory tract
- entry: inhalation -> mouth or nose; drops, moisture, and dust particles
- disease: common cold, pneumonia, TB, influenza, measles, small pox
- Gastrointestinal tract
- entry: food, water, contaminated fingers; most mo's entering body destroyed by HCl and enzymes in stomach; bile and enzymes in small intestines
- disease: hep A, typhoid fever, cholera, etc; pathogen eliminated in feces and can be transmitted to other hosts
- Genitourinary tract
- entry: sexual contact
- disease: STDs
How do MO get into body through the parenteral route?
MO have a preferred portal of entry. If they enter some other way, will you get symptoms?
How do MO "adhere" to the host cell?
Things called "adhesin" that cling onto receptors on the host cell.
How do capsules help invading MO fight the host defense?
Prevents phagocytes from adhering to them.
How does the cell wall of the invading MO helps fight the host defense? (2 types)
M protien: heat and acid resistant. mediates attachment of phagocytes.
Waxy lipid: resists digestion from phagocytes.
What causes the "blackening" of an infected site?
How does invading MO penetrate host's cytoskeleton by rearranging the actin?
Gram negative type IV secretion system secrete what?
Gram negative type III secretion system secrete what?
What is Yersina?
Limits phagocytosis and immune signaling.
Innate vs. adaptive immunity?
- Innate: any pathogen
- Adaptive: specific defense
Our first line of defense consists?
- Normal microbiota
Our second line of defense consists?
- Natural killers
What is our third line of defense?
Where to B-cells mature? T-cells? Lymphocytes?
- Bone barrow
- Lymph nodes
Peripheral lymphoid organs do what? (3 things)
- Trap antigens
- Initiate immune response
- Signal recirculation of lymphocytes
What role does dendritic cells have in immunity?
Take material and present them to T-cells.
What chemical is released by a damaged cell that causes vasodilation?
What are the 3 pathways of antimicrobial activation? How are they activated?
Alternative - does not involved ab. initiated by complement proteins and pathogens
Lectin - marcophage ingest, sti. liver to release lectins.
Classical - Ab binds to Ag
The complement system produced by the liver destroys microbes in what three ways? Other than those three ways, what other functions do they have?How can MO evade this system?
- recruit phags
- puncture cells causing lysis
- unite specific and non-specific to act as one
- Surface lipid-carbs prevent MAC formation
- enzymes digest C5.
What is opsonization? Who carries this out?
Process of coating a MO so that phags can recognize and eat. Opsonins carries this out.
What role do toll like receptors play in immunity?
Attach to MO and induce cytokines. (they say that this right here is a fucka that needs to be messed with)
What do alpha, beta and gamma interferons do?
Alpha/beta inhibit viral replication
Gamma causes neutros and phags to phagosize bacteria
How do natural killers destroy a MO?
- Release perforin
- creates pore
- fluid goes in
What's in the humoral component of the adaptive system?
Extracellular and B-cells everything else is cellular component.
B-cells mature where and is part of the cellular or humoral response system?
T-cells mature where and is part of the cellular or humoral response system?
B-cells and T-cells recognize which: Intact and fragment antigens.
What do antibodies bind to?
CD4 and CD8 goes with what mhc class? (think of making both equal 8)
What is the variable region of the immunoglobulin?
The part of the antibody that binds to the antigen
vertebrates produce millions of antibody proteins, if they only have a few
hundred genes coding for those proteins?
DNA rearrangement & somatic mutation
What is junctional diversity?
DNA sequence variations introduced by the improper joining of gene segments during the process of V(D)J recombination.
What are the 5 immunological classes? (like sounds like GMA TV!)
What are the functions of each?
- IgG: enhance phags, neutro toxins, activate, complement system, protect newborns
- IgM: agglutinates microbes, first to respond
- IgA: protects mucAs
- IgD: innitiate immune response on B-cells
- IgE: allergy and parasites
Which immunological class is the first to arrive? IgG IgM IgA IgD IgE?
Which is most abundant in body?
Which is most abundant in serum?
What is the "clonal selection" of the B-cell?
mature B-cell shas it's own immunoglobulins on surface. Sees something, attaches to it and some B-cells proliferate to memory while most into anti-body producing plasma cells.
How do MHC-I work with CD8 (cytotoxic T-cells) to destroy the virus?
MHC-I are on nucleated cells. If something invades it, MHC-I takes a piece and presents it outside. CD8 is the only one that sees this and if it does, it destroys it.
Naturally acquired natural and passive immunity?
Natural: immunity from exposure or some transfer of antibodies from immune donor.
- Passive: antibodies without having to look for a
- "donor". like birth, or breast milk.
artificially acquired vs artificially passive immunity?
Arti acquired: vaccine
Arti passive: transplant of precursor antibodies (bone marrow transplant)
What is the Edward Jenner experiment?
Cowpox rubbed on skin. Ab formation and memory. Rubbed second time = rapid and intense immune response.
Inactivated polio vacc. from monkey's kidney. inactivated by formalin.
oral polio vaccine with weakened live virus.
Difference between Attenuated whole-agent and Inactivated whole-agent vaccines and Toxoids?
Attenuated: Weakened, lifelong immunity, no booster
Inactivated: MO has been killed
Toxoids: aimed at toxins produced by pathogen. boosters every 10. like tetanus.
What are subunit vaccines?
- Uses antigen fragments
- can't reproduce in body
What are recombinant vaccines?
Uses other microbes programmed for antigenic fraction.
What are acellular vaccines?
Use fractions of a bacterial cell
What are conjugated vaccines?
Used for children with low response to vaccines due to capsular polysaccharides.
What are nucleic acid vaccines?
Newest type not used yet. Naked DNA
What is the most safest and effective way to prevent disease in children?
What is the ELISA test?
Unknown antigen is placed on an enzyme. Antibodies are then showered on it. The enzyme will use a signal(chromogen) if the right antibody forms with the antigen.
What are monoclonal antibodies?
Antibodies that are produced in a lab from a single B-cell.
What is the difference in procedure between direct and indirect ELISA?
Antibody put first.
Antigen put first.