Microbiology Chapter 13 Flashcard

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question
Define infection, disease, and infectious disease
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1. Infection: pathogenic microorganisms penetrate the host defenses, enter the tissues, replicates

2. Disease- Pathologic state that results when the infection damages or disrupts tissues and organs-

3. Infectious disease: the disruption of a tissue or organ caused by microbes or their products
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Know sites of body that harbor biota
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On skin or contiguous mucous membranes
Upper Respritory Tract
Gastrointestinal tract
Outer opening of Urethra
External genitalia
Vagina
External Ear Canal and Eye
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Sites that are Sterile (do not harbor Biota)
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All internal tissues and organs (See list Below)
Heart and Circulatory system
Liver
Kidney and Bladder
Lungs
Brain and Spinal Cord
Muscles
Bones
Ovaries/tested
Glands
Sinuses
Middle and inner ear
Internal eye

FLUIDS WITHIN AN ORGAN OR TISSUE
Blood
Urine in kidneys, ureters, bladder
Cerebrospinal fluid
Saliva prior to entering oral cavity
Semen prior to entering the urethra
Amniotic fluid surrounding the embryo and fetus
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Define microbial antagonism and endogenous infection
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Microbial antagonism-Suppress pathogens so you don’t get sick

Endogenous infection-The microbe is already there in your body (Ear infections)
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Factors that weaken the immune system
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Old age and extreme youth

Genetic defects in immunity and acquired defects in immunity (AIDS)

Surgery and organ transplant

Organic disease: cancer, liver malfunction, diabetes

Chemotherapy/immunosuppressive drugs

Physical and mental stress

Other infections
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Define virulence factor
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any characteristic or structure of the microbe that contributes to its virulence


Virulence- the degree of pathogenicity
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Know portals of entry including which one is the most common
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• Nicks, abrasions, and punctures

• Intact skin is very tough- few microbes can penetrate

• Some create their own passageways using digestive
enzymes or bites

• GI Tract

• Pathogens contained in food, drink, and other ingested substances

• Adapted to survive digestive enzymes and pH changes

• Respiratory Portal- #1 Portal of Entry

• Urogenital Portals of Entry

• Sexually transmitted diseases (STDs)

• Enter skin or mucosa of penis, external genitalia, vagina, cervix, and urethra

• Some can penetrate an unbroken surface

• Pathogens that Infect During Pregnancy and Birth

• Some microbes can cross the placenta (ex. the syphilis spirochete)

• Other infections occur perinatally when the child is contaminated by the birth canal
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Source of infectious agent
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Exogenous- outside the host
Endogenous- part of the host
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Microbe enters the tissues of the body by a portal of entry
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Usually a cutaneous or membranous boundary

Normally the same anatomical regions that support normal biota
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Know the acronym TORCH and what each letter stands for
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TORCH (toxoplasmosis, other diseases, rubella, cytomegalovirus, and herpes simplex)
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infectious dose
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amount of bacteria required to actually cause an infection
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Toxigenicity:
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the power to produce toxins
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Toxinoses:
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a variety of diseases caused by toxigenicity
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Toxemias:
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toxinoses in which the toxin is spread by the blood from the site of infection (tetanus and diphtheria)
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Intoxications
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toxinoses caused by ingestion of toxins (botulism)
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Be able to recognize what is a sign and what is a symptom and Define Syndrome
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Sign: any objective evidence of disease as noted by an observer

Symptom: the subjective evidence of disease as sensed by the patient

Syndrome: when a disease can be identified or defined by a certain complex of signs and symptoms
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Signs
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Fever
Septicemia
Microbes in tissue fluids
Chest Sounds
Skin eruptions
Leukocytosis
Lukopena
Swollen lymph nodes
Abscesses
Tachycardia (increased heat rate)
Antibodies in serum
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Symptoms
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Chills
Pain, ache, soreness, irritation
Malaise
Fatigue
Chest tightness
Itching
Headache
Nausea
Abdominal Cramps
Anorexia
Sore throat
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Difference between septicemia and bacteremia/viremia
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Septicemia: general state in which microorganisms are multiplying in the blood and are present in large numbers

Bacteremia or viremia: microbes are present in the blood but are not necessarily multiplying
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Know portals of exit
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Respiratory and Salivary Portals - Coughing, sneezing , talking and laughing
Skin Scales
Fecal Exit
Urogenital Tract
Removal of Blood or Bleeding
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Know the examples of latent infections
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Herpes simplex

Herpes zoster

Hepatitis B- more of a chronic condition, escalates over time

AIDS-infected viral count goes up for about 2 weeks, then viral count goes back down over next few months, viral count gets very low but never 0, after several years the viral count goes back up, this is stage 4 and is actual AIDS

Epstein-Barr
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Reservoir:
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the primary habitat in the natural world from which a pathogen originates
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Source:
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the individual or object from which an infection is actually acquired
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Carrier: AKA (living reservoirs)

Asymptomatic carriers
Incubation carriers
Convalescent carriers
Chronic carriers
Passive carrier
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an individual who inconspicuously shelters a pathogen and spreads it to others without any notice

Asymptomatic carriers- no sign or symptoms

Incubation carriers - spread infections agent during the incubation period

Convalescent carriers- continue to shed viable mircobes and convey infection to others.

Chronic carriers - shelters the infectious agent for a long period after recovery because of the latency of the infections agent

Passive carrier- someone that carriers infection from one person to another (such as a dentist)


NON LIVING RESERVOIRS- soil and water
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Vector:
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a live animal that transmits an infectious agent from one host to another
Majority are arthropods
Larger animals can also be vectors
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Biological vector:
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actively participates in a pathogen’s life cycle
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Mechanical vectors:
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transport the infectious agent without being infected
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Define zoonosis
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an infection indigenous to animals but naturally transmissible to humans

–Ex. Rabies, we can get the disease but cannot give it to other humans.
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Know the difference between communicable and non-communicable disease (ESSAY)
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Communicable disease: when an infected host can transmit the infectious agent to another host and establish infection in that host
1. Transmission can be direct or indirect
2. Contagious agent: highly communicable


Noncommunicable disease: does not arise through transmission of the infectious agent from host to host

1. Acquired through some other, special circumstance

2. Compromised person invaded by his or her own microbiota

Individual has accidental contact with a microbe in a nonliving reservoir
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Know how communicable diseases are spread direct vs. indirect (ESSAY)
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Patterns of Transmission-

- Contact -
Direct (kissing, touching)
Droplets - talking and spit saliva
Vertical- from mother to child during birth
Vector- a person carries it from one patient to another

- Indirect Vehicles-
Formites- person touches door knob
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Fecal-oral contamination can also lead to both of these types of transmission (above and below)
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Food, water, biological products-

Air- Droplet nuclei(inhaled through mouth) and aerosols produced by cars
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Vehicle:
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any inanimate material commonly used by humans that can transmit infectious agents (food, water, biological products, fomites)
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fomites
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Contaminated objects (doorknobs, telephones, etc.)
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Nosocomial infections:

and the #1 form of nosocomial infection
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infectious diseases that are acquired or develop during a hospital stay
2-4 million cases a year

Urinary Tract Infections is #1
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Define etiological agent and how you would determine what the agent is
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• Etiologic agent: the causative agent

• Kosh's 4 postulates is how you would determine what the agent is.
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Epidemiology:
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the study of the frequency and distribution of disease and other health-related factors in defined human populations
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Prevalence
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the total number of existing cases with respect to the entire population
Prevalence = (total number of cases in population / total number of persons in population) x 100 = %
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Incidence Rate
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the number of new cases over a certain time period

Incidence = number of new cases / total number of susceptible persons
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Mortality rate:
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the total number of deaths in a population due to a certain disease (# of deaths / entire population)
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Morbidity rate:
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the number of persons afflicted with infectious diseases
(# of people infected / total population x 100= %)
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Define epidemic, pandemic, sporadic, and endemic occurrence
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Endemic -Outbreak is spread within a defined pattern
Epidemic- no defined pattern, spread is sporatic, but does have large case numbers
Sporadic Occurance- no defined pattern and low case numbers
Pandemic- global spread
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