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83 Cards in this Set
- Front
- Back
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Define pathogen |
A microbe that causes disease |
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Define pathogenesis |
The process by which a pathogen causes disease |
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Define infection |
The replication of a pathogen in/on a host |
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Define primary pathogen and give an example |
A microbe that readily causes disease in healthy hosts. Entamoeba is an example (gives fatigue, fever, loss of appetite, bloody stool, diarrhea, flatulence, etc.). |
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Define opportunistic pathogen and give an example |
A microbe that only causes disease when it is in an unusual location or when an immunocompromised individual is exposed to it. E. coli is an example. |
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Define ID50 |
The dose of the pathogen where 50% of the people exposed to the it will get the disease. |
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Bacillus anthracis: what disease does it cause and what type of pathogen is it? |
Anthrax Primary |
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Bordetella pertussis: what disease does it cause and what type of pathogen is it? |
whooping cough Primary |
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Borellia burgdorferi: what disease does it cause and what type of pathogen is it? |
Lyme disease Primary |
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Cornynebacterium diphtheriae: what disease does it cause and what type of pathogen is it? |
Diphtheria Primary |
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Escherichia coli O157:H7: what disease does it cause and what type of pathogen is it? |
Hemorrhagic colitis Primary |
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Helicobacter pylori: what disease does it cause and what type of pathogen is it? |
Gastritis/ulcers Primary |
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Mycobacterium tuberculosis: what disease does it cause and what type of pathogen is it? |
Tuberculosis Primary |
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Salmonella Typhi: what disease does it cause and what type of pathogen is it? |
Typhoid fever Primary |
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Salmonella Typhimurium: what disease does it cause and what type of pathogen is it? |
Salmonellosis Primary |
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Treponema pallidum: what disease does it cause and what type of pathogen is it? |
Syphilis Primary |
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Vibrio cholerae: what disease does it cause and what type of pathogen is it? |
Cholera Primary |
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Yersinia pestis: what disease does it cause and what type of pathogen is it? |
Plague Primary |
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Define serovar |
Variant based on cell surface antigens |
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Clostridium botulinum: what disease does it cause and what type of pathogen is it? |
Botulism Opportunistic |
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Clostridium difficile: what disease does it cause and what type of pathogen is it? |
Colitis Opportunistic |
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Clostridium tetani: what disease does it cause and what type of pathogen is it? |
Tetanus Opportunistic |
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Escherichia coli (uropathic): what disease does it cause and what type of pathogen is it? |
UTIs Opportunistic |
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Haemophilus influenza: what disease does it cause and what type of pathogen is it? |
Meningitis Opportunistic |
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Klebsiella pneumoniae: what disease does it cause and what type of pathogen is it? |
Pneumonia Opportunistic |
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Legionella pneumoncystic: what disease does it cause and what type of pathogen is it? |
Pneumonia, septicemia --> Legionnaire's disease Opportunistic (when it gets in old people's lungs) |
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Listeria monocytogenes: what disease does it cause and what type of pathogen is it? |
Meningitis, septicemia Opportunistic |
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Mycoplasma pneumonia: what disease does it cause and what type of pathogen is it? |
Atypical pneumonia (walking pneumonia) Opportunistic |
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Neisseria meningitides: what disease does it cause and what type of pathogen is it? |
Meningitis Opportunistic |
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Pseudomonas aeruginosa: what disease does it cause and what type of pathogen is it? |
Pneumonia, skin infection Opportunistic |
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Staphylococcus aureus: what disease does it cause and what type of pathogen is it? |
Skin infection, toxic shock Opportunistic |
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Streptococcus pneumoniae: what disease does it cause and what type of pathogen is it? |
Meningitis, pneumonia Opportunistic |
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Define Case |
A person who is infected and has symptoms |
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Define Asymptomatic Carrier |
An infected individual who does not exhibit symptoms of the disease |
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What does CI stand for? What does it mean? |
Case-to-Infection ratio The proportion of infected people who develop the disease |
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Define virulence |
The capacity of a pathogen to cause disease |
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How do pathogens cause disease? List the steps |
Gain entry to the host Attach to and invade specific host cells/tissues Evade host defenses Obtain nutrients from the host Offspring exit the host |
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What are the routes of transmission of infectious disease? |
Direct human contact (blood-borne, air-borne, sexually transmitted) Indirect contact (food/water-borne, fomite-mediated, vector-borne) Zoonotic transfers |
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What does fomite refer to? |
inanimate objects |
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What are zoonotic transfers? |
transferring a disease from 1 species to another |
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What are virulence factors? |
Molecules produced, or behaviors exhibited, by a pathogen that contribute to its pathogenicity. |
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What was the virulence factor in Frederick Griffith's S strain? |
The capsule |
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How do viruses attach to cells? |
They use a very specific interaction between a viral attachment protein and a cell receptor. This triggers virus/genome entry. |
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How do bacteria attach to our cells? |
They use adhesins such as fimbrae/pili or lipoteichoic acid |
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What is determines the pathogen's host range? |
The group of organisms to which the pathogen is able to infect. |
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Describe the emergence of the broad host range of Parvovirus? |
Mutations enabled the parvovirus to infect foxes and dogs as well as cats (the original target). |
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How do pathogens overcome the challenge of penetrating intact skin? |
They survive on the skin in ready position or associate with biting insects |
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How do pathogens escape the mucin layer? |
They avoid binding to mucin, some can move through viscous materials (spirochetes), some take advantage of M cells, and others degrade the mucin (using proteases). |
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How do pathogens resist antibacterial peptides? |
They use peptidases (to kill them), have proteins that counter permeabilizing effects of channels, or they have a negatively charged LPS in their outer membrane (disguise them). |
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How do M cells work? |
They are designed for pinocytosis. They drink in antigens in the process. T cells, macrophages, try to activate B cells so they will make antibodies (secreted IgA (sIgA) --> secreted into the lumen of the GI tract where it binds to mucin and gets flushed out of the body). |
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What type(s) of pathogen(s) use M cells to gain access to the body? |
Salmonella and Shigella |
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How do pathogens escape from sIgA? |
They have sIgA proteases to break them down. |
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How do pathogens get into host cells? |
They can use invasins and induce phagocytosis (and survive once inside). |
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How do invasins work? |
They mimic the host proteins that control actin polymerization and depolymerization (trick the cell into letting them in). |
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How do pathogens survive after phagocytosis? |
They can escape the phagosome, prevent acidification of lysosome, or they detoxify the chemicals from oxidative bursts (by producing catalase and/or superoxid dismutase). |
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What are capsules? What are they made of? |
Extracellular matrix of polymers that surrounds some bacterial cells. They are commonly composed of polysaccharides, proteins, or a mixture of polysaccharides and proteins. |
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How does the complement system work? |
??? |
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What is chemotaxis? |
The movement of a motile cell or organism, or part of one, in a direction corresponding to a gradient of increasing or decreasing concentration of a particular substance.
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What are opsons? |
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How do pathogens prevent complement activation? |
Prevent binding of activation factors. Binds host molecules (e.g. sialic acid) that degrade. |
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How do pathogens prevent migration of phagocytes? |
Proteases may specifically degrade anaphylatoxins. Toxins inhibit oxidative burst or kill phagocytes. |
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How do pathogens evade antibodies? |
Antigen variation (change their surface proteins so that the antibodies won't bind to them) and camouflage with host proteins. |
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Which pathogen takes our proteins and binds them to itself so that it can hide from antibodies? |
Legionella |
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Which pathogens change their surface proteins so that antibodies won't recognize them? |
Neisseria, Streptococcus, and Mycoplasma |
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What are exotoxins? |
Soluble proteins that are transported or released outside the bacterial cell. |
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Describe the parts of A-B toxins. |
A: Enzymatically active B: Membrane-binding |
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What makes a cardiac cell different from a kidney cell? |
The specific genes they express and therefore, the specific proteins they possess. |
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What are some of the specific targets of Shiga toxin in humans? Why do they target these specific tissue types? |
Kidney, liver, and neurons. They produce globotriaosylceramide. |
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Where does the Shiga toxin come from? |
E. coli O157:H7 |
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What types of animals don't produce globotriaosylceramide? What does this have to do with E. coli O157:H7? |
Cows, sheep, deer, and pigs. E. coli O157:H7 can live inside them without killing the animal (host) |
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How do A-B toxins exert their toxic effects? |
The B subunit binds to a diphtheria toxin receptor, which causes endocytosis. Once in the endosome, a lysosome fuses with the endosome and it starts pumping in protons. The decreased pH causes the dissociation of the A and B sub-units. The B subunit turns into a channel in the lysosome which allows the A subunit to get into the cytoplasm. |
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What type of enzymes are the diphtheria pertussis, and cholera toxins? |
Transferases: specifically ADP-ribose transferases. |
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What does EF2 stand for? |
Elongation Factor 2 |
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What is the difference between paralysis caused by botulism toxin and paralysis caused by tetanus toxin? |
Botulism causes flaccid paralysis (can't contract muscles) and tetanus causes spastic paralysis (muscles can't relax). |
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Describe the botulism toxin pathway? |
The A subunit of the botulism toxin breaks down SNARE proteins, which causes Ach not to be secreted, which results in flaccid paralysis. |
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How do cytolysins work? |
khg |
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How does the alpha-toxin of S. aureus work? What is the benefit to what it does? |
kl |
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How does listeriolysin work? Where does it come from? What is the benefit to what it does? |
jkl |
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How does lecithinase work? Where does it come from? What is the benefit to what it does? |
ljk |
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What are the possible mechanisms of cytolysins? Give an example of each. |
Pore formation in plasma membrane, pore formation in endosome membrane, and phosholipases. Alpha-toxin of S. aureus, listeriolysin of Listeria, and lecithinase of C. perfringens. |
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How do superantigens work? |
ljk |
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What is a CD4+ T cell? What do they do? |
kjh |
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Describe toxic shock syndrome. |
lkj |
