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57 Cards in this Set
- Front
- Back
Epidemiology
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study of health events and disease, their distribution, and associated factors in a defined population.
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What are the goals of Epidemiology?
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-Define the disease
-Identify outbreaks -Assist in developing treatments -Develop prevention |
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What requires a chain of events that must occur unbroken to allow one human to infect another?
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transmission of disease
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Explain the chain of infection transmission.
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A pathogenic organism must live and reproduce in a reservoir. The reservoir may be a human, insect, animal, or soil. The pathogen must have a portal of exit and a mode of transmission. Mode of transmission may be through something like an insect bite, nasal droplets, or semen. Therefore mode of transmission can be direct or indirect. Then the pathogen gain entry to a victim through the portal of entry; some examples are oral mucosa, skin abrasion, skin puncture, etc. Finally, the pathogen must enter a susceptible victim where the pathogen can have a breeding ground and reproduce. The typically victims are immune compromised, malnourished, and unimmunized.
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What is an inanimate object that transmits a pathogen to a new host?
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fomite
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What is it called when an microorganism is found in a host and is not a disease and does not cause harm?
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colonization
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Can a colonization be transmitted to others?
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Yes
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True or False
A colonization is a balance between the host and organism. |
True.
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During mode of transmission, what is direct transmission?
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direct contact between the reservoir and new host
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During mode of transmission, what is indirect transmission?
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is where the reservoir deposits the organism on a fomite
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Name the two host defense systems.
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1. Innate Immune System
2. Specific Immune System |
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Name some examples of the innate immune system.
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1. NK cells
2. secretions 3. phagocytes 4. mechanical barriers |
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What is the most cost effective method of altering pathogen susceptibility with a developed vaccine?
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immunization
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What is the ability of a microorganism to latch onto and gain entrance into its host?
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microbial adherence
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What is the movement of cells according to chemical gradient that attract them?
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chemotaxis
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What are the two major categories of viruses?
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1. DNA
2. RNA |
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What are the smallest known infective agents?
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viruses
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What must enter the host's cell to replicate?
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viruses
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What can adhere to the cell's wall and inject genetic material?
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viruses
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what type of mode of transmission is there direct contact between the reservoir and new host?
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direct transmission
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what type of mode of transmission is where the reservoir deposits the organism on a fomite?
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indirect transmission
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How do you reach infection control?
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You must break one of the chains in the chain of transmission.
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Name some ways to control infection.
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-hand washing
-antibiotics -antiviral drugs -destroying the nonhuman reservoirs & vectors -immunization -blocking portal of exit (mask) -improving diet |
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What is the most important way to control infection?
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wash your hands
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How does the pH of the skin act as a barrier?
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the skin's pH of 5.4 is not a desirable host to bacteria. bacteria like moist and humid environments.
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How does mucus act as a barrier?
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the mucus lining of the lungs has cilia that catches bacteria and sweeps them away. mucus also has antimicrobial chemicals that destroy bacteria.
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How are sebaceous glands a protective barrier?
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the sebaceous glands secreations act as antifungals
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What is Lactoferrin and where is it located?
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It is located in the mucosa of the oral cavity. Lactoferrin is a mucosal protein that reduces iron availability and limits bacterial growth.
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How do GI cells act as a barrier?
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They turn over every three days not giving bacteria time to adhere to them.
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What is the herd immunity?
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it is the idea to decrease the number of illnesses and diseases by immunizing a high percentage of the population
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Explain the host-microbial balance.
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the host a microbe have a symbiotic relationship. these microbes are referred to as colonization and they protect the host from harmful microbes.
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When does the host-microbial relationship become imbalanced?
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When the host is immunocompromised and the body's resident flora actually become pathogenic
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What facilitates microbial adherence?
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-direct penetration (surgical wound, insect bite)
-attach to host's epithelial cells with their glycocalyx |
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Explain the bacterial enzymes.
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they help the organisms to spread and invade tissues. most of them with dissolve or hydrolyze blood, collagen or connective tissue
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Explain encapsulation.
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this capsule prevents recognition or binding of antibodies therefore the body does not see it as foreign and it doesn't get phaocytized
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What is the mircoorganism's ability to cause disease called?
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virulence
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What is the microorganism's ability to mutate in response to the environment called?
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anitmicrobial resistance
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Explain endospore.
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-allows microorganisms to survive harsh environments.
-it protects the DNA and cytoplasm -gram + bacteria |
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What is the motile appendages that allow bacterium to swim or move toward nutrients called?
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flagella
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What are toxins that microorganisms produce that can affect the host's cells systemically or locally?
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endotoxins and exotoxins
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What causes illness and death by binding to specific receptors in target organs?
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exotoxins
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What interferes with vital metabolic pathways?
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exotoxins
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What toxins are always gram-negative bacteria
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endotoxins
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What are common causative agents with septic shock?
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endotoxins
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What toxin is part of the cell wall on the bacteria and triggers immune response when bacterium lyses?
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endotoxin
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Which are less harmful; endotoxins or exotoxins?
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exotoxins
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What are single-celled organisms that have no organelles?
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bacteria
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Name the four types of cell walls.
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1. gliding bacteria
2. spirochetes 3. mycoplasmas 4. rigid bacteria |
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Name the three possible shapes of bacteria
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1. cocci (round & non-motile)
2. bacilli (rods & half motile) 3. spiral |
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Name two types of staining.
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Gram +
Gram - |
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Which staining is dark purple?
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Gram +
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Which staining is pink?
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Gram -
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What contains ecoding information for reverse transcriptase enzyme?
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retroviruses
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What does the reverse transcriptase enzyme allow for?
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it creates mRNA to DNA from its own genome.
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Why is the reverse transcriptase enzyme so serious?
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it cause permanent mutation to host cells because every time cell replicates it replicates the viruses DNA.
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What are microorganisms that are harmless and do not cause disease in host but it can be transmitted to others?
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colonization
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Explain antibiotic resistance.
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the principle of antibiotic resistance is that society has overused antibiotics incorrectly. the majority of people never complete the prescription of antibiotics therefore creating bacteria resistance organisms
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