Exam 4 Study Guide Flashcards
List blood formed elements and describe their functions.
- Bone marrow: tissue in the long bones of arms and legs; all cells originate from bone marrow
- Thymus: above the breast bone; cells go from the bone marrow to the thymus to develop
- Spleen: filters the blood for dead red blood cells and filters infection of white blood cells
innate immunity
inbuilt immunity to resist infection
o Main players: anatomical defenses, inflammation, fever, phagocytosis, complement proteins
acquired immunity
immunity established to adapt to infection
o Specificity, tolerance, and memory
List innate immune system components protecting Genito-Urinary Tract
• Mucous membranes that line the cavities, continual shedding of it
• Microbial antagonism:
o Normal flora that compete with pathogens for specie and nutrients – promote overall health by providing vitamins to the host
what does acquired immune tolerance mean?
• The ability to produce antibodies against nonself antigens while “tolerating” (not producing antibodies against) self antigens. T cells are an example
compare the layers of skin and mucous membrane and their role in the immune system
• Skin: Perspiration (high salt), Sebaceous glands secrete oil (low pH)
- Lysozyme- destroys cell wall of bacteria
- Epidermis, Tightly packed layer of cells, Shedding of dead cells
• Mucous Membrane: Line body cavities open to the outside
- Epithelium: Thin layer composed of tightly packed
live cells
- Continual shedding of cells carries attached germs
away
what are the elements of the first line of defense?
o Normal flora (bacteria and yeast)
o Epithelium
o Skin
o Macrophages in the lungs
what are the elements of the second line of defense?
o Lipases, nuclease, protease, lysozymes
o Macrophages
o Serum proteins
o Complement proteins
what are the elements of the third line of defense?
o IgG, IgM, IgA, IgE
o Cytokines
o Antibody-mediated Immunity (AMI) and Cell-Mediated Immunity
Name the primary and secondary lymphoid organs, where are all blood components are originated?
- Primary: bone marrow
- Secondary: spleen, lymph nodes, tonsils, lymphatic tissue, MALT, SALT, and BALT
- All blood components come from the bone marrow
Describe how lymph nodes and spleen are involved in immune system
• Lymph nodes: collect free liquid and put back into the body for circulation
o Pea sized organs
o Contain white blood cells
o Trap any incoming bacteria
o Under the armpits and groan
o Lymphoid tissue: drainage and collection field
• Spleen: apart of the blood system
o Filters the blood for red blood cells
o Filters out infection from the blood (with WBC)
Name the elements involved in nonspecific immunity, Give examples for each.
- Prevents pathogens from entering into the body
- First line of defense
- This includes the skin, mucous membranes of the respiratory, digestive, and urogenital tracts
how is fever produced?
• Pyrogens (chemicals) trigger the hypothalamus to increase the body’s core temperature, temperature over 37C (98.6 F)
which molecules may induce fever?
o Various types of pyrogens
o Bacterial toxins
o Cytoplasmic contents of bacteria released by lysis
o Antibody-antigen complexes (inflammation)
o Interleukins-1 (IL-1)
• Muscle contractions, increased metabolic activity, and constriction of blood vessels/reduced blood flow, raises the temperature
define inflammation and list its major characteristics
• The release of inflammatory mediators from injured tissue cells initiates
• a cascade of events which result in the signs of inflammation
o nonspecific response to tissue injury due to infection or physical means
o Cardinal signs, redness, warmth, pain, swelling, and altered function
acute inflammatory response
o Quickly developed, beneficial, promotes healing
o events which result in elimination of invading pathogens
o capillary dilation and increased blood flow
o temperature rise stimulates inflammatory response
o restrict pathogen movement
o Recruit phagocytes to the area
chronic inflammation
slow process
o Slow and causes permanent tissue damage
what are the complements and what are their functions?
- Apart of the second line of defense
- A group of plasma proteins that plays a major role in innate immunity.
- Lyse foreign cells, formation of membrane attack complex, Lysis (MAC)
- Attracts phagocytes to the area (chemotaxis)
- Aid phagocytes in doing their job (opsonization)
- Group of 20 or more proteins that bind and destroy infection and are normally not active
- Bind to the surface of bacteria and accumulate (complement fixation) – poke a hole and kill it
briefly compare classical vs. alternate complement pathways
• Classical: The antibody-dependent pathway of complement activation; it stimulates lysis of pathogens, phagocytosis, and other host defenses.
• Alternate: An antibody-independent pathway of complement activation.
o Initiated by repetitive structures on bacteria, like the membrane LPS
o Inflammation and microbial cell lysis
what is the role of acute-phase response proteins in complement fixation?
- Liver proteins that assist in the prevention of blood loss and ready the host for microbial invasion
- Bind to bacterial surfaces and act as opsonin and activate the classical component pathway
What does de-granulation refer to? Which cells are involved?
- De-granulation: apart of the Mast cells, which are bone marrow-derived cells that differentiate in connective tissue
- Mast cells are not phagocytic but when stimulated they rapidly release the contents of their granules in the extracellular environment
what are some examples of granules that are produced?
histamine, prostaglandins, serotonin, heparin, dopamine, platelet-activating factor, and leukotrienes
name several phagocytic cells
• Macrophages, dendritic cells, neutrophils, and eosinophils
what are the main characteristics of macrophages?
involved in phagocytosis; engulfing and ingesting cells infected with bacteria and viruses
o APC = antigen processes cells – detect infection and remove them, process this info and present to T-cells
what are the main characteristics of dendritic cells?
phagocytic cells, more involved in APC than other cells
o Reside primarily in the skin and lungs
define lysosome
• A spherical membranous eukaryotic organelle that contains hydrolytic enzymes and is responsible for the intracellular digestion of substances.
what is the role of lysosome in phagocytosis?
• Phagocytosis: process by which monocytes, macrophages, neutrophils, and dendritic cells recognize, ingest, and digest extracellular microbes. Binds to microbe. Internalize it. Fuse it with lysosome. Digest the microbe
• Different chemicals within lysosomes will degrade the bacteria depending on the type
o Lipases: kills cell membrane
o Nuclease: kills DNA and RNA
o Protease: kills enzymes
o Lysozymes: kills the cell wall
role of neutrophils
Phagocytic (PMN), Major defense against extra-cellular infections
role of T-helper cells
Main players in acquired immunity (CMI)
role of cytotoxic T cells
directly attack target cells infected with intracellular pathogens such as viruses and cancer cells
role of NK cells
Kill malignant cells and cells infected with pathogens
cell-mediated immunity (CMI)
The type of immunity mediated by T cells
o Main players: T helper, cytotoxic T cells, and NK cells
o Effects: altered self-cells, cells infected with viruses, intracellular bacteria, and tumor and cancer cells
Humoral (antibody-mediated) immunity (AMI)
The type of immunity that results from the presence of soluble antibodies in blood and lymph.
o Main players: B cells (antibodies)
o Effects: neutralize toxins, neutralize viruses, marks invaders for attack by immune system components, activate complement system, aids in phagocytosis, and stimulates inflammation
list lymphocytes
B cells, T cells, and NK cells
what are the differences between plasma cells and memory B cells?
• B cells are what is remembered after an infection; they can be kept for months, years, or lifetimes. When an antigen is detected, the B cells turn into plasma cells which produce antibodies that are released and are temporary cells
What does antigen-presenting mean (APC)? List the cells involved in this process?
- Detect infection and remove it; they will also process the information and present it to T-cells to be able to later recognize the infection
- Book definition: Cells that take in protein antigens, process them, and present peptide fragments bound to MHC molecules to T cells
- Cells involved: T-cells, macrophages, dendritic cells, and B cells
natural immunity and examples
acquired through the normal life experiences of a human and is not induced through medical means
o Active natural: person developing their own immune response to a microbe (infection)
o Passive natural: receiving immunity from another person (maternal antibody)
artificial immunity and examples
produced purposefully through medical procedures (immunizations)
o Active artificial: person developing their own immune response (vaccination)
o Passive artificial: person receiving immunity from another (immune globulin therapy)
IgG
major circulating antibody
IgM
first to appear after infection
IgA
major antibody in secretions
IgE
involved in allergic reactions
define opsonization
coating of microbes by serum proteins, which assist with recognition/ingestion by phagocytic cells
What is the effect of opsonization? Name three opsonin molecules
- Effects: molecules that carry out above are called opsonins, such as antibody and complement proteins; bind to microbial cells, coating them for phagocyte recognition
- Three types: acute phase proteins, C-reactive protein (CRP), and mannan-binding lectin (MBL)
Explain different ways macrophages recognize infectious agents and phagocytized them.
- Macrophages identify an infection, Bind to the infectious agent, engulf it, and destroy
- different surface receptors that allow them to bind to and destroy infectious agents.
- Can identify and bind to foreign antigens because they have receptors for cell surface molecules for structures like Pilli, fimbrae, lipopolysaccharides (LPS)
- Can bind to the antigen that the Fc group of an antibody and destroy it through phagocytosis
Why oxygen consumption increases (respiratory burst) during infections
• reactions occur as soon as phagosome is formed
• toxic oxygen products are produced which can kill invading microbe
o these biproducts include: Peroxide, Superoxide, Hydroxyl radical
What are the characteristics of primary and secondary immune response to infection
- When initially exposes to an infection or an antigen, the immune system takes several days to produce a response to that antigen and produce a small amount of antibodies.
- IgM is the first anti-body produced during an immune response, it is the primary antibody produced upon first exposure to a novel antigen.
- When the immune system is exposed to the antigen again, there is a much quicker response to the antigen because of memory B cells and memory T cells.
- The major anti-body produced during a secondary infection is IgG, which is the major circulating anti-body. In addition, the anti-bodies produced typically have greater affinity for the antigen. The immune system has a much more effective response to the infection
Define and list characteristics of antigen, which molecule is the most antigenic.
- Foreign molecules that include: pili, flagella, cell wall, cell membrane
- The molecule that is most antigenic is proteins
Describe how blood cell count (WBC, RBC, Interferon, etc.) laboratory results may be interpreted?
- RBS does not have an influence on infection rates
- High neutrophils means bacterial infection
- High lymphocytes means viral infection
- High eosinophils means parasite infection
- Interferon: free bacteria, largest phagocytic cells in the blood
define immune-complex
- Immune complexes is the interaction between antigens and anti-bodies, which is called the immune complex formation. referred to the interaction between antigens and anti-bodies.
- complement fixation: complement proteins become active and begin destroy target cells by poking holes in them. Classical pathway
aggulation
when anti-bodies bind to insoluble bacterial cell antigens, causing the bacteria to cross-link and clump up. Visible clumps or aggregates of cells or particles; prevents the bacteria from being effective
immunoprecipitation
used to detect soluble antigens, binding of bivalent or multivalent antibodies to antigens forms lattice that precipitates, lattice formation occurs only when there is an optimal ratio of antigen to antibody
opsonization immune complexes
coating of microbes by serum proteins, which assist with recognition/ingestion by phagocytic cells
o Molecules that carry out above are opsonin, such as antibody and complement proteins
o Bind to microbial cells, coating them for phagocyte recognition
what is hypersensitivity?
When the immune response occurs in an exaggerated form and results in tissue damage to the individual
type 1 hypersensitivity
A form of immediate hypersensitivity arising from the binding of antigen to IgE attached to mast cells, which then release anaphylaxis mediators such as histamine. Examples: hay fever, asthma, and food allergies.
type 2 hypersensitivity
A form of immediate hypersensitivity involving the binding of antibodies to antigens on cell surfaces followed by destruction of the target cells (e.g., through complement attack, phagocytosis, or agglutination).
o IgG or IgM antibodies are inappropriately directed against host cell-surface antigens
o Mismatched blood transfusions is an example
type 3 hypersensitivity
A form of immediate hypersensitivity resulting from the exposure to excessive amounts of antigens to which antibodies bind. These antibody-antigen complexes activate complement and trigger an acute inflammatory response with subsequent tissue damage.
o Too many IgG or IgM are produced and not gotten rid of and can trigger an inflammatory response
o Can affect blood vessels, kidneys, and joints
type 4 hypersensitivity
A delayed hypersensitivity response that results from the binding of antigen to activated T lymphocytes, which then release cytokines to trigger inflammation that damages tissue. Type IV hypersensitivity is seen in contact dermatitis from poison ivy, leprosy, and tertiary syphilis.
list immunodeficiency deseases
• Chronic granulomatous disease, X-linked agammaglobulinemia, DiGeorge syndrome, and severe combined immunodeficiency disease (SCID), HIV, malnutrition, severe stress, HIV, and meningitis
What is meant by primary and acquired immunodeficiency?
• Primary: congenital; result from genetic or developmental effect; develop in infants and young children
• Acquired: develop as a direct consequence of some other recognized cause, develop later in life
o Examples include HIV, severe stress, or malnutrition
toxoid vaccines
Chemically or thermally modified by bacteria toxins. Useful for some bacterial diseases/ Stimulate antibody-mediated immunity/ Require multiple doses
o DTP and Tetanus vaccines
attenuated vaccines
o Mild infections/no disease, strong immune response/ triggers CMI
o Viral vaccines trigger a cell-mediated immune response
o Results in herd immunity
o Problems: with reversion, with immunosuppressed, with pregnant
inactivated vaccines
o Problems: May causes inflammatory response and no herd immunity
o Antigenically weak, and needs high or multiple doses, or the incorporation of an adjuvant, to make the vaccine more effective, (also may produce allergic reactions)
what are cytokines?
Soluble proteins or glycoproteins that act as mediators
o released by one cell population that act as intercellular mediators or signaling molecules
o Immune system horomones, inhibit or grow cells, chemotaxis, apoptosis
MHC proteins
collection of membrane proteins (glycoproteins)
o Receptor molecules are like fingerprints
o On all cells except RBC
o Two classes of them
CSF
proliferation; fight infection, promote healing
TNF
kills cells; necrosis factor (tumor necrosis factor)
interferons
fight against viruses; protect other cells
MCH1
Tc (cytoxic T cells) – kills infected cells because cancer cells have different MCH1 receptor molecules
o Kills cells with viruses as well
MCH2
T helper cells; MCH2 cells react, tell T helper cells, produce B cells, which produce plasma cells to make antibodies against the antigen
What are some practical uses of ELISA test? Differences between direct and indirect ELISA?
- Can be used to detect antigens or antibodies in a sample
- Direct ELISA: detects antigen
- Indirect ELISA: detects antibody produces in response to antigen
rheumatic fever
type 2 – myocarditis, heart valve scarring, and arthritis
hemolytic anemia
type 2 – red blood cells
Graves disease
type 2 – thyroid stimulating hormone (TSH)
multiple sclerosis
types 2 and 4 – antibodies and activated T cells, nerves
myasthenia Gravis
type 2– skeletal muscle, neurotransmitter receptors
Lupus
type 3 – DNA, nucleoprotein, cardiolipin, and blood clotting components
type 1 diabetes
type 3 – T cells and pancreatic beta cells
define graft-host disease
Graft cells attack the recipient tissues like in bone marrow transplants
• disease prevented by treating donor with immunosuppressive drugs to deplete marrow of mature T cells
Why are organ transplants often rejected?
MHC compatibility is hard to achieve between the donor and host; T helper cells recognize that the foreign MHC molecules on the transplanted tissue and aid cytotoxic T cells or releases cytokines to destroy the organ
why are fetuses not rejected by the mother?
The fetus is not a privileged site but is not rejected
• Rejection is prevented by the many different immunosuppressive mechanisms
• Early embryos do not express MHC class I and II molecules on the placental layer that is in contact with maternal tissues
• Cytokines that enhance MHC expression have no effect on placental cells
• T cells are prevented from functioning in the placenta to reject the fetus
What is the importance of monoclonal antibody? How can you make them?
• Monoclonal antibodies are used to detect infections
isolate B cells from animals that can produce antibodies to a certain disease
Inject HIV into a rabbit, kill it and isolate the spleen and the B cells in it, the primary cells will die but mix it with cancer cells to keep a stock of different antibodies of different diseases
alveolar macrophages
- A vigorously phagocytic macrophage located on the epithelial surface of the lung alveoli, where it ingests inhaled particulate matter and microorganisms.
- These cells ingest and kill most inhaled microorganisms by phagocytosis
lactoferrin
- An iron-sequestering protein released from macrophages and neutrophils into plasma.
- Found in breast milk and mucous secretions
- Sequester iron reducing its availability to invading microbial pathogens thereby limiting their ability to multiply
granulocytes
- A type of white blood cell that stores preformed enzymes and antimicrobial proteins in vacuoles near the cell membrane.
- Contain reactive substances that kill microbes and enhance inflammation
agranulocytes
cells that lack granules and include monocytes (which mature into dendritic cells and macrophages) and lymphocytes
haptens
small organic molecules; not antigenic by themselves but may become antigenic when bound to larger carrier molecule e.g., penicillin
epitopes
antigenic determinant sites; An area of an antigen that stimulates the production of, and combines with, specific antibodies; also known as the antigenic determinant site.
adjuvants
Material added to an antigen in a vaccine preparation that increases its immunogenicity; can be any nontoxic material that prolongs antigen interaction with immune cells, assists in processing of antigens by antigen presenting cells, and nonspecifically stimulates the immune response to the antigen
serology
study and diagnostic use of antigen-antibody interactions in serum
neutralization
Binding of specific immunoglobulins to toxins or viruses, inhibiting their biological activity; antibodies prevent binding
widal test
diagnostic for typhoid fever – agglutination
hem-agglutination
used to indicated the presence of virus specific antibody
flow cytometer
used to directly count microbes and to gain detailed information about them; creates a stream of cells so narrow that one cell at a time passes through a beam of laser light; as each cell passes through the beam, the light is scattered
Normal microbiota (flora) may significantly impact human health and disease.
true
What are the major characteristics of group of Clostridium?
- Gram positive bacilli
- Spore forming
- Obligate anaerobe
- Highly toxigenic
Clostridium perfringenes
gangrene
Clostridium tetani
tetanus; neurotoxin that disturbs muscle and nerve communication, contracts muscles, like with lockjaw
Clostridium botulinum
also produces a neurotoxin, disturbs muscle and nerve communication, relaxes muscles that normally contract like the diaphragm
CDAD
clostridium defficile associated diarrhea
o Toxins a and b dissolve connections between tissues
o Antibiotic associated diarrhea
o Damages cytoskeleton, causing colitis (damage of colon), damage to pseudo
List major virulence factors involved in attachment
pili or fimbriae
list major exotoxins
AB exotoxins, specific host site exotoxins, membrane-disrupting exotoxins, super-antigens that stimulate T cells directly to make cytokines
exotoxins
soluble, heat-labile, proteins, produced and released, highly immunogenic, some highly lethal
o Produced by Gram + and Gram -, but mostly +
o Often travel from site of infection to other tissues or cells where they exert their effects
o Diphtheria, tetanus, whopping cough
endotoxins
LPS, outerembrane of Gram – bacteria, toxic component is the lipid portion, lipid A, can leak out as bacteria grows, but is released when bacteria dies or is lysed
o The effects of this is coagulation, inflammation, internal bleeding, septic shock (release of cytokines), organ damage, fever (macrophages to release endogenous pyrogen)
chronic infections
persisting over a long time
acute infections
short but severe
latent infections
persisting in tissues for long periods, during most of which there are no symptoms
opportunistic infections
resulting from endogenous microbiota, especially when host resistance is very low
mycobacteria
thick, waxy cell wall, lipid, acid fast
spirochetes
spiral, Lyme disease, syphilis
vibrio
cholera, curved
Gram negative bacilli
Enterobacteriaceae, E. coli, salmonella, shigella
gram positive bacilli
bacillus and clostridium, endospores
gram negative cocci
Neisseria, gonorrhea, meningitis, pneumonia
gram positive cocci
staph, cluster, strep chains
what are the characteristics of Streptococcus pyogenes?
o Gram +
o Mild to life threatening diseases: Sore throat, cellulitis (flesh eating)
o Treated with penicillin
o Virulence factors: M protein and capsules (antiphagocytic), hyaluronidase (dissolves connective tissues), streptolysin (endotoxin that kills WBC, RBC, and epithelial cells)
o Types of infections: impetigo (skin infection, very contagious), erysipelas (patches of redness on face and chest), necrotizing fasciitis (destroys tissue, permanent scarring, flesh eating, can be systemic, kill within a few days), respiratory infections. Sore throat, rheumatic and scarlet fever
o Systematic/invasive diseases
what are the characteristics of Staphylococcus aureus?
gram positive and cocci
o Infections: folliculitis (pimple), infection of a hair follicle, sty, furuncles, carbuncles (multiple rashes clumped together), MRSA, scalded skin syndrome, impetigo, wound infections, toxic shock syndrome (superantigen), food poisoning
o Virulence: coagulase (prevent immune system WBC to reach it, insulate around not destroy it), hemolysin (kills RBC), protein A (kills Ab), exfoliation (SSSS – staphylococcal scalded skin syndrome)
bacterial meningitus
Streptococcus pneumoniae
- Leading cause of meningitis in adults
- Only encapsulated strains are virulent
o Neisseria meningitidis (Meningococcal meningitis)
- Fimbria, capsule, and LOS
- Can become epidemic
o Haemophilus influenzae (Vaccine available)
viral meningitus
o Milder and more common form of meningitis
o Mostly caused by Enterovirus entering body via GI tract or inhalation
o Similar signs and symptoms as bacterial, Examine CSF, if no bacteria, it is viral
o No specific treatment exists
fungal meningitus
o Cryptococcal Meningitis
List several microorganisms that may live on human skin
- Coagulase-negative staphylococci Diphtheroids Cutibacterium acnes Staphylococcus aureus Streptococcus spp.
- Bacillus spp. Malassezia furfur Candida spp. Mycobacterium spp. (occasionally)
What is the significance of Lactobacillus acidophilus colonizing the human body? Where do you expect to find this microorganism?
- Döderlein’s bacillus. They ferment glycogen produced by the vaginal epithelium, forming lactic acid. As a result, the pH of the vagina and cervix is maintained between 4.4 and 4.6, inhibiting other microorganisms. In addition to L. acidophilus, metagenomic sequencing has identified a variety of anaerobic Gram-negative and Gram-positive bacteria
- Genitourinary Tract and skin
List cells, structures and materials involved in protecting lung against infectious agents.
• Cilia and hairs (protect bacteria from going into lungs), alveolar macrophages, normal flora, mucociliary blanket (coats the mucosal surfaces of lower portions of the respiratory system), microbes are transported outwards with coughing and sneezing, and saliva washed microbes out of the mouth and into the stomach
T/F; Recent research has demonstrated a correlation between the presence of certain types of Gram-positive bacteria in the human gut with obesity and type 2 diabetes
true
Define Microbiome. What is the purpose of Human Microbiome Project?
- The sum of all the microorganisms that live on and in the human body.
- Provide knowledge regarding microbes in the human body, understood that there is no one single healthy microbiome, understood that it is microbes are influenced by environment, diet, medications, and other factors, and the overall role of microbes in our lives
Define opportunistic pathogen and their impact on Compromised hosts
- A microorganism that is usually free living or a part of the host’s normal microbiota but may become pathogenic under certain circumstances, such as when the immune system is compromised.
- Typically happens a bacteria infects a host outside their typical niche; find hosts that will meet growth and replication requirements
Do Microbes Make People Fat? Briefly explain this concept
- Demonstrated through fecal matter transplants
- Bacteria help our body to digest short-chain fatty acids (SCFAs) like butyrate, propionate, and acetate. Butyrate is the principle source of calories for intestinal epithelial cells which causes the calories to not be as high. Propionate travels to the liver where it inhibits cholesterol synthesis, and along with butyrate helps regulate weight by increasing the release of intestinal hormones that suppress hunger. On the other hand, acetate is readily absorbed by a variety of host cells and acts as a precursor for lipid synthesis in liver and fat cells. But this also depends on what you eat as well. We have a lot of control over the environment of our microbiome
Briefly discuss the development of human normal Microbiota
• It is a selective process that is determined by body location, age, gender, diet, nutrition, and environment
Discuss the use of Fecal Transplant in treating some bacterial diseases
- Can be associated with weight gain
- Obsess donors give FM to germ free mice, which after the transplant these mice started to develop obesity without any change in their diet or exercise routine
- It is because they have different bacteria that perform at different rates
What are the target cells for HIV? What are the major targets of anti-HIV drugs?
- CD4+T cells like macrophages, dendritic cells, and monocytes
- Goal is to make the viral loads undetectable
What is the most efficient mode of HIV transmission? What is the most common mode of HIV transmission?
• Blood transfusions; sexual contact
Why it is very difficult to develop a vaccine against HIV infection?
- viral envelope proteins continually change their antigenic properties – high mutation rate
- also the virus stays in the memory of CD4+T cells
Explain the Koch’s postulate. Why it is not applicable to some diseases
- One bacteria must be able to be cultured from a disease
- This is not applicable to all diseases because some, like syphilis, are not able to be cultured in a lab environment
- Poly-microbial infections and not all diseases caused by microbes
list the reservoirs of infection
animal, human, and nonliving
What are the modes of transmission of infectious diseases?
• Contact (direct or indirect), vehicle. And vector-borne
etiology
study of the origin of disease
epidemiology
study of the origin, cause, and spread of disease
nosocomial infections
An infection that is acquired during a patient’s stay in a hospital or other type of clinical care facility.
o UTI
o Associated with old age, weakened immune system, and hospitalization
What is meant by pathogenicity Islands? Give examples
- A segment of DNA in some pathogens that contains genes responsible for virulence; often codes for a type III secretion system that allows the pathogen to secrete virulence proteins and damage host cells.
- Yersinia spp., P. aeruginosa, Shigella flexneri, Salmonella spp., enteropathogenic Escherichia coli
List Microbial virulence factors involved in bacterial pathogen invasion and dissemination
• Coagulase (solidify the blood around bacteria), collagenase (dissolves tissues to allow bacteria to spread), hemolysin (destroys RBC), leukocidins (destroys WBC), protein A and G (destroys antibodies), hyaluronidase (destroys glue between tissue, spreading factor), and streptokinase (removes clots to spread bacteria)
Compare Chlamydia and Neisseria
- Chlamydia; mistaken for a virus because it is small and an obligate intracellular parasite and lacks ATP, enters through abrasions or laceration in conjuctctiva and mucus membrane, causes lymphogranuloma vereeenum, PID, mostly asymptomatic, most common STD in the US, affects both sexes, highest prevalent in teenage girls, can increase risk for cervical cancer, has both elementary bodies and reticulate bodies
- Gonorrhea: caused by Neisseria gonorrhea, has pili and lipooligosaccharide, men experience painful urination and pus filled discharged, women have a higher chance of contraction but no symptoms, PID, eye infections
Compare (necrotizing fasciitis) flesh-eating bacteria infection and gangrene
- Gangrene: apart of clostridium, entry through trauma and puncture wounds, symptoms: pain and swelling at injury site, fever, foul-smelling drainage, cuts the supply of oxygen to tissue, rapid growth and spread, produces N2, H2, and CO2 gases, produces toxins, treatment is surgical removal of dead tissues and antibiotic treatment
- Flesh-eating bacteria: apart of streptococcus, necrotizing fasciitis, rapid treatment to prevent death, antibiotic treatment, destroys the sheath covering skeletal muscles, inflammation and destruction of skeletal muscle and fat tissue, penetrate in a wound or bruise, and releases exotoxins
What are the characteristics of food poisoning (Intoxication)? What are the two major causes of food poisoning?
- Toxins from contaminated food cross mucous membranes of the intestinal tract; injesting a pre-formed toxin; can beta, alpha, or enterotoxins
- Potato salad and similar foods are likely sources; accumulates in high starch foods
- superantigens
- Growth of bacteria that produce enterotoxin (relatively heat stable)
- Enterotoxins are super antigens - cause severe diarrhea (no fever, water non bloody)
- Nausea, vomiting, diarrhea, cramping
- Develops quickly: Four to six hours
- Causes: Staphylococcus aureus, Clostridium botulinum
lobar pneumonia
involves the entire lobes of the lungs
primary atypical pneumonia
caused by mycoplasma
pneumococcal pneumonia
streptococci
histoplasmosis
systematic fungal infection
pneumocystis pneumonia (PCP)
caused by fungus
what are prions?
An infectious agent consisting only of protein; prions cause a variety of spongiform encephalopathies such as scrapie in sheep.
list diseases caused by prions
these diseases are called transmissible spongiform encephalopathles (Degenerative central nervous system diseases in which the brain has a spongy appearance; due to prions.), and these diseases are scrapie, kuru, Creutzfeldt-Jakob disease (CJD), variant Creutzfeldt-Jakob disease (vCJD), Gerstmann-Sträussler-Scheinker disease (GSD), and fatal familial insomnia (FFI).
Name and describe the stages that occurs during the course of infectious disease
- Initial exposure to the microbe
- incubation period: The period after pathogen entry into a host and before signs and symptoms appear. Reproducing but has not yet appeared, this time period depends on pathogen
- prodromal stage: The period during the course of a disease when signs and symptoms are present, but they are not yet distinctive enough for an accurate diagnosis. Patient is often contagious
- followed by an illness period, when the disease is most severe and displays characteristic sigs and symptoms, host immune response is triggered
- then there is a period of decline and recovery, called convalescence
infections
The invasion of a host by a microorganism with subsequent establishment and multiplication of the agent. An infection may or may not lead to overt disease. When a microorganism is growing and multiplying on or within a host, ranges in severity
infectious diseases
Any change from a state of health in which part or all of the host’s body cannot carry on its normal functions because of the presence of an infectious agent or its products.
opportunistic pathogens
A microorganism that is usually free living or a part of the host’s normal microbiota but may become pathogenic under certain circumstances, such as when the immune system is compromised. Typically immunocompromised because they are away from their typical niche
zoonoses
A disease that can be transmitted from animals to humans. Animals can be a reservoir
virulence factors
different components of a pathogen that facilitate their survival around a host, such as mycobacterium
vectors
In epidemiology, it is a living organism, usually an arthropod or other animal, that transfers an infective agent between hosts.
extracellular pathogens
organisms that remain in tissues and fluids but never enter host cells during the course of the disease
o Example: Yersinia pestis (the plague)
intracellular pathogen
microbes that grow and multiply within host cells
facultative intracellular pathogen
those organisms that reside within the cells of the host or in the environment but can also be grown in pure culture without host-cell support
o Example: brucella abortus replicates within macrophages, neutrophils, trophoblast cells and histoplasma capsulatum is a fungus that grows within phagocytes but can be replicated in vitro
obligate intracellular pathogens
incapable of growth and multiplication outside a host cell, all viruses are this type of pathogen – require host cell for replication
o Examples: some bacterium can be this like chlamydia and rickettsia – rocky mountain fever. Cannot be grown in the lab outside their host cells. Also malaria parasites as well
communicable diseases
A disease associated with a pathogen that can be transmitted from one host to another.
epidemic
a disease that suddenly increases in occurrence above the normal level in a given population.
common-source epidemic
An epidemic characterized by a sharp rise to a peak and then a rapid but not as pronounced decline in the number of individuals infected; it usually involves a single contaminated source that infects individuals.
propagated epidemic
An epidemic that is characterized by a relatively slow and prolonged rise and then a gradual decline in the number of individuals infected. It usually results from the introduction of an infected individual into a susceptible population and transmission of the pathogen from person to person.
What were the goals of Biological Weapons Defense Initiative?
- (1) the first-ever procurement of specialized vaccines and medicines for a national civilian protection stockpile;
- (2) invigoration of research and development in the science of biodefense;
- (3) investment of more time and money in genome sequencing, new vaccine research, and new therapeutic research;
- (4) development of improved detection and diagnostic systems;
- (5) preparation of clinical microbiologists and clinical microbiology laboratories as members of first-responder teams in the event of a bioterror attack.
List and define diseases/toxins classified under Category A of “Pathogens and Toxins Defined by the CDC as Select Agents
• Botulinum neurotoxins, Ebola, Marburg, variola major virus (smallpox), variola minor (alastrim)
Define and Give Examples of Arthropod-Borne Diseases
- transmitted by bloodsucking arthropods (e.g., ticks, mosquitoes, certain types of flies) from one vertebrate host to another. They multiply in the tissues of their arthropod hosts without producing disease.
- Examples: chikungunya, dengue (DENV), dengue hemorrhagic, equine encephalitis, west nile fever (encephalitis), zika (ZIKV),
Briefly discuss Coordinated efforts in Preventions and Controlling Epidemics
- Help to trace source of food-borne disease with serotyping
- Detect antibodies
- reducing/ eliminating the source or reservoir of infection
- break the connection between the source of the infection and susceptible individuals
- reduce the number of susceptible individuals and raise the general level of herd immunity
give examples of emerging pathogens
Bartonella henselae, Ehrlichia spp., Helicobacter pylori, Borrelia burgdorferi; Encephalitozoon spp., Cryptococcus gattii strains; Acanthamoeba spp., Babesia spp.; Australian bat lyssavirus, Hendra virus, Hepatitis C virus, Hepatitis E virus, Human herpesvirus 8, Human herpesvirus 6, Parvovirus B19, MERS-CoV, Avian influenza A (H7N9), Bourbon virus, Chikungunya virus, Nipah virus
give examples of reemerging pathogens
Clostridium (Clostridioides) difficile, Streptococcus pyogenes, Staphylococcus aureus, Bordetella pertussis; Ebola virus, Measles virus, Mumps virus, Enterovirus A71, Enterovirus D68, Polio virus, Dengue virus, Zika virus
droplet nuclei
• In an airborne transmission, pathogen is suspended in air droplets, Small particles (0 to 4 μm in diameter) that represent what is left from the evaporation of larger particles (10 μm or more in diameter) called droplets., can form from salvia, mucus, or other body fluids, can be airborne for hours or days and travel long distances
airborne transmission
• The spread of a pathogen as it travels suspended in air over 1 meter or more from the source to the host. It is suspended in droplets, droplet nuclei, or dust
formites
- Common inanimate materials that transmit pathogens to humans.
- Vehicle transmission
- Examples include surgical instruments, drinking vessels, stethoscopes, bedding, eating utensils, and clothing
tropism
• The movement of living organisms toward or away from a focus of heat, light, or other stimulus. (2) The selective infection of certain organisms or host tissues by a virus due to the presence of the specific receptor to which the virus binds
Briefly Describe Mechanisms of Action Exotoxins (Fig 35.8)
- This AB toxin binds to the cell receptor within clathrin-coated pits by the B subunit. The intact toxin is endocytosed, and the pH change within the endosome causes the subunits to separate. An endosome in which
- this separation occurs is sometimes called a compartment of uncoupling of receptor and ligand (CURL). The B subunit is then recycled. The active toxin (A) subunit exerts its effect on its target, in this case the elongation factor-2 (EF-2) of protein synthesis, by enzymatically attaching an ADP-ribose to EF-2. The altered EF-2 is inhibited from assisting in protein synthesis, leading to cell death.
- This channel-forming (pore-forming) toxin inserts itself into the host cell membrane, forming a channel (or pore). Multiple membrane pores result in an osmolarity shift, as water enters the cell and cytoplasmic contents move out. The resulting effect of this toxin is cell lysis.
Define Superantigens. Give examples.
- Toxic bacterial proteins that overstimulate the immune system.
- Toxins a and b, toxic shock syndrome
T/F: Some exotoxins can act as superantigen.
true
infectious dose
Refers to the number of organisms that infect 50% of an experimental group of hosts within a specified time period.
lethal dose
Refers to the number of organisms that kills 50% of an experimental group of hosts within a specified time period.
signs
An objective change in a diseased body that can be directly observed (e.g., a fever or rash).
symptoms
A change during a disease that a person subjectively experiences (e.g., pain, fatigue, or loss of appetite). Sometimes the term symptom is used more broadly to include any observed signs.
syndrome
A set of signs and symptoms that are characteristic of a disease.
the plague
• Zoonotic disease, vector borne, two forms as bubonic or pneumonic, carried by rodents and then transferred from fleas, virulence factors: adhesions, capsules, and phagocytic failure, facultative intracellular pathogen – grows in macrophages. NO VACCINE
rabies
- Zoonotic disease; bite or scratch from an infected animal; signs & symptoms: if you show symptoms you’re dead, but pain and itching at infection site, hydrophobia, and hallucinations; commonly come from raccoons, skunks, foxes, and coyotes
- Treatment: post exposure prophylaxis: rabies immune globulin, antibodies, and a vaccine
malaria
Caused by plasmodium, spread by mosquito, endemic in 100 countries, fever and chills every 2-3 days b/c of RBC, anemia, fatigue, and jaundice, protozoa (parasite), can be become dormant or recurrency and relapse, there is a vaccine but not needed in the US, can take chloroquine as a preventive method (preventative)
TB
mycobacterium tuberculosis, acid-fast, phagocytic failure, can be killed with heat, can leave the lung and become systemic (lymph nodes), immunocompromised most at risk, leading killer of HIV, intracellular pathogen, cell wall is toxic to humans, vaccine available but not widely in the US
• Signs and symptoms: fever, bloody cough, difficulty breathing, wheezing, night sweat, fatigue and weight loss
HAV
hepatitis A; food-borne; fecal-oral; subclinical, acute infection, vaccine available
HBV
hepatitis B; blood, needles, body secretion, placenta, sexual, vaccine
HCV
hepatitis C; blood, sexually, vaccines
Influenza
• Immunopathology, made up of pieces and N and H proteins can shift and drift, type A infection is the most dangerous, pieces mix and match, secondary bacterial infection possible, new vaccines produced every year, other drugs can lessen the symptoms and shorten course of diseases such as amantadine, Tamiflu, and Relenza
dental caries
• Streptococcus mutans – colonizes teeth, produce lactic acid from sugar metabolism, and produce glucans from sucrose, adherence of bacteria to specific receptors on teeth, dietary sugar drops pH in the mouth, which causes calcium phosphate in teeth to dissolve and bacteria to take over
syphilis
• Chancre sore, fever, rash, stroke, nervous system deterioration, treponema pallidum, primary to quaternary levels, sexual contact, non-culturable, treat with antibiotics
peptic ulcer
• Helicobacter pylori, stomach ulcer that could become cancer, flagella to attach to stomach lining, has urease, which is an enzyme that takes urea into ammonia then ammonia hydroxide to increase pH, antibiotics for 2 weeks
cystitis
UTI, Caused by E. coli, burning sensation with urination, 8x more common in women due to a shorter urethra, can cause a kidney infection if left untreated,
septicemia
- Enterobacteriaceae that has spread to the blood, originates outside the blood stream, endotoxin is released and antibiotics can enhance endotoxin release, macrophages can try to contain it but can fail which is how it ends up in the blood, and lungs are susceptible to irreversible damage
- G (-) more fatal than G(+), shock despite treatment; Escherichia, Pseudomonas
- Symptoms: Violent shaking chills/fever; accompanied by rapid heart breathing
- In case of septic shock: Urine output drops, Respiration and pulse become more rapid Arms and legs become cool and dusky colored
lyme disease
• Zoonotic disease, tick-borne, caused by borrelia burgdorferi, spirochete, simple red rash (bull’s eye) to neurological symptoms to severe arthritis (most due to immuno-pathology), starts with flu-like symptoms first, endemic in the eastern part of the country, easily treated if caught early, use insect repellent with DEET, no vaccine
Leishmaniasis
• Cutaneous, mucocutaneous, and visceral ulcers, disease of poverty associated with malnutrition, displacement, poor housing, and discrimination, reservoirs are canines and rodents and use sand flies as intermediate hosts, papule at infection
