Vol.3-Ch.10 "Infectious Diseases and Sepsis" Flashcards
(77 cards)
What is the first individual to introduce an infectious agent called?
The Index Case
What are normal flora?
The normal bacteria in our body that don’t cause problem and are a part of our Host Defenses and produce an environment that is not livable for pathogens
What are Opportunistic Pathogens?
What are Pathogens?
Opportunistic Pathogens are ordinarily non harmful bacteria that cause disease only under unusual circumstances.
Pathogens are disease producing microorganisms
What are bacteria?
They are microscopic single celled organisms. They are classified as Prokaryotes b/c they do not have a distinct nuclear membrane and possess only one chromosome in the cytoplasm. They reproduce independently but require a host for nutrients.
They are easily identified by their staining or appearance under a microscope
What is the Gram Stain test?
It is the most common method of differentiating different bacteria.
If PURPLE it is POSITIVE
If RED it is NEGATIVE
What are the 3 appearance categories of bacteria?
Which are Gram Stain positive or negative?
- Cocci or Spheres (Staphylococci, Streptococci) are
round and are Gram Positive - Rods (Enterobacter sp., E. Coli) are elongated and are
Gram Negative - Spirals (Spirochetes, Vibrio) are coiled
Exotoxin VS Endotoxin
- Exotoxin:
are poisonous proteins shed by bacteria during
bacterial growth. They are more dangerous of the 2.
The body CAN create antibodies against this, but heat
also destroys these - Endotoxin:
consist of proteins, polysaccharides, and lipids. They
come from the bacterial cell wall and are released
when the bacterial cell is destroyed. The body
CANNOT create antibodies against this unless BOTH
the protein and polysaccharide portions are present.
ONLY gram negative bacteria make endotoxins.
Bactericidal VS Bacteriostatic Antibiotics?
Bactericidal Antibiotics kill bacteria
Bacteriostatic Antibiotics inhibit bacterial growth and reproduction
What are Viruses?
Viruses are much smaller than bacteria and require an electron microscope instead of just a microscope.
They cannot reproduce themselves and therefore must get inside a host cell and take it over so that it can make the cell itself grow and produce other virus bodies. This is why they are called OBLIGATE INTRACELLULARPARASITES (not prokaryotes or eukaryotes).
B/c they live inside a host cell it resists antibiotics and makes it hard to kill b/c it will also kill the cell.
A common one is the common Cold
What are Prions?
A new class of disease producing agents that are referred to as “slow viruses”. They are not prokaryotes or eukaryotes but are actually protein particles that fold in a way that Proteases (enzymes that break down proteins) cannot act on them.
These collect in the nervous system and brain tissue, destroying them and giving them a spongy appearance on gross examination.
Remember this is what causes they Creutzfeldt-Jakob disease
What are Fungi?
They are plant like microorganisms that are mostly not pathogenic. Examples are yeast, mold, and mushrooms. Usually not a problem unless the pt has HIV or is taking a lot of antibiotics that kill the normal flora and allow an environment that does not inhibit fungal growth
What are Protozoa?
Single celled parasitic organisms with flexible membranes and can MOVE. Most live in soil and ingest decaying organic matter. May enter the body through fecal-oral route or mosquitos. Causes malaria and form of gastroenteritis
What are Parasites?
Common where sanitization is very poor. Round worms live in the intestinal mucosa. Diagnosis is done by finding eggs in stool
What are Pinworms?
Common in Civilized countries. Tiny worms that live in the distal colon and crawl onto anal mucosa to lay eggs while the host sleeps. Typically only cause an itchy butt but is very contagious and runs rampant in institutionalized kids. One rounds of antibiotics usually kills them
What are Hookworms?
They hook onto barefeet and travel to the intestines where they grip and irritate the intestinal wall and feed on blood. Epigastric pain and anemia are possible
What is Trichinosis?
Contracted through raw or poorly cooked pork. The females lay thousands of eggs that travel to the skeletal muscle and each creates a cyst that stays. Causes GI disturbances, edema (especially in eyelids), fever, and others. Death may result if they travel to the heart, lungs, or brain
What are infectious RESERVIOIRS?
Animals, humans, insects, and the environment
What are the 2 basic ways that diseases can spread?
- Direct:
cough, sneeze, kiss, or sexual contact - Indirect:
Received from environment like touching a doorknob,
handrail, or keyboard
Communicable VS Contamination VS Infection
Communicable is the ABILITY of diseases to be transmitted
Contamination is when the agent only exists on the surface of the host
Infection is when the agent actually penetrates the host
What are the 5 things that infection probability depends on?
- Correct mode of entry
- Virulence (the disease’s strength or ability to infect
and overcome the body’s defenses - Number of organisms Transmitted (dose)
- Host Resistance
- Other host factors (age, status, population, travel
tendency, ect)
Latent Period VS Communicable Period VS Incubation Period
Latent Period is when the pt is first infected and CANNOT infect others
Communicable Period is the pt may now start to show symptoms and CAN infect others
Incubation Period is the time between exposure to presentation of S&S
Seroconversion VS Window Phase VS Disease Period
Seroconversion is when a person takes a test for antibodies developed against a disease to see if it is present, sometimes a person has the disease and tests negative but then later the antibodies form and then the test becomes positive; this is Seroconversion
Window phase is the time between exposure and Seroconversion (or the development of antibodies)
Disease Period is the time from onset of symptoms until the resolution of the disease normally or death of host
What are the three major body defense systems?
- Immune system
- Complement system
- Lymphatic System
Lymphocytes are in charge of what respose?
Cell mediated and Humoral
Cell mediated uses T lymphocytes and does not end in antibody production but Humoral uses B lymphocytes and does end in antibody production (autoimmunity is the dark side of humoral immunity).