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Microbiology > Chapter 14 - Infection, Infectious Diseases and Epidemiology > Flashcards

Chapter 14 - Infection, Infectious Diseases and Epidemiology Flashcards

To better memorize and understand Microbiolody

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1
Q

Symbiosis

A

“to live together”

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2
Q

What are the different types of symbiosis?

A

Mutualism, Commensalism, Parasitism

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3
Q

What is Mutualism?

A

both members benefit from their interation.

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4
Q

What is commensalism?

A

One member of the relationship benefits without significantly affecting the other. -Ex: Staphylococcus epidermidis growing on the skin typically causes no measureal harm to a person.

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5
Q

What is Parasitism?

A

One member benefits and the other is harmed

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6
Q

What is a Pathogen?

A

Any parasite that cuases disease

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7
Q

Normal Microbiota

A

The microbes that colonize the surfaces of the body without normally causing disease

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8
Q

What are the two main types of normal microbiota?

A

Resident microbiota and transient microbiota.

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9
Q

What is resident micrbiota?

A

They remain a part of the normal microbiota of a person throughout life. - found on the skin and mucous membranes of digestive tract, upper respiratory tract, dital portion of the urethra and vagina.

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10
Q

What is transient Microbiota?

A

They remain in the body for only a few hours, days or months before disappearing. Found in the same locations as resident micrbiota but cannot persist because of competition.

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11
Q

What are opportunistic pathogens?

A

Microorganisms that cause disease when the immune system is suppressed, when microbial antagonism is reduced, or when introduced into an abnormal area of the body. Normal microbiota that cause disease under certain circumstances.

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12
Q

What are the conditions that are provided for opportunistic pathogens?

A
  1. Introduction of normal microbiota into unusual site in body. 2. Immune suppression. 3. Changes in the normal microbiota
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13
Q

What is microbial antagonism (microbial competition)?

A

Changes in relative abundance may allow opportunity for a member to thrive and cause disease.

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14
Q

What are reservoirs of infection?

A

Sites where pathogens are maintained as a source of infection.

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15
Q

What are three types of reservoirs of infection?

A

Animal reservoirs, human carriers, and nonliving reservoirs

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16
Q

Describe Animal Reservoirs: - What are Zoonoses? - How are zoonoses aquired?

A

Zoonoses: Diseases that spread naturally from their usual animal hosts to humans. They are aquired by direct contact with animal or its waste, eating animals, and bloodsucking arthropods.

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17
Q

Describe Human Carriers.

A

Infected individuals can be asymptomaticf but infective to others. Some individuals eventually develop the illness while others never get sick. Healthy carriers may have defensive systems that protect them.

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18
Q

Describe Non living Reservoirs

A

Examples: Soil, water adn food reservoirs of infection Microorganisms due to contamination by feces or urine Milk, meat, and vegetables also harbor pathogens.

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19
Q

What are Portals of Entry?

A

They are sites through which pathogens enter the body.

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20
Q

What are four major portals of entry?

A
  1. Skin 2. Mucous membranes 3. placenta 4. Parental route
21
Q

What is contamination?

A

The presence of microbes in or on the body

22
Q

Define Infection.

A

A successful invasion of the body by a pathogen.

23
Q

What is pathogenicity?

A

The ability of a microorganism to cause disease.

24
Q

What is Virulence?

A

The degree of pathogenicity The relative ability of a pathogen to infect a host and cause disease.

25
Q

What are the factors that contribut to virulence?

A
  1. Adhesion factors 2. Biofilms 3. Extracellular enxymes 4. Toxins 5. Antiphagocytic factors
26
Q

Portal of Entry: Skin

A
  • out layer of skin composed of relatively thick layers of tightly packed, dead, dry cells,that acts as a barrier to pathogens. - Pathogens enter through openings or cuts. - Pathogens capable of burrowing into skin layers
27
Q

Portal of Entry: Mucous Membranes

A

Line the body cavities that are open to the environment -Provide a moist, warm envirnoment hospitable to pathogens -Respiratory Tract is the most common site of entry (nose, eyes, mouth) - Gastrointestinal tract may be route of entry (must survive the acidic pH of the stomach)

28
Q

Portal of Entry: Placenta

A

-developing embryo forms an organ called the placenta which it obtains the nutrients from the mother. - cross the placenta and infect child (spontaneous abortion, birth defects, premature birth)

29
Q

Portal of Entry: Parental route

A

A means by which the portals of entry can be circumvented. - pathogens deposted directly into tissues beneath the skin or mucous

30
Q

What is the role of Adhesion in infection?

A
  • Adhesion: the process by which microorganisms attach themselves to cells.
  • Adhesion Factors: to accomplish adhesion. They are specialized structures or attachment proteins. (e.g. adhesion disks, hooks, suckers)
  • Ligands: viruses and bacteria have surface lipoprotein and glycoprotein molecules which enable them to bind to completmentary receptors on host cells
         Also called: Adhesins (bacteria) and attachment proteins (viruses)

Attachment proteins help in adhesion (found on viruses and bacteria) Viral or bacterial ligands bind to host cell receptors. The interation can be determine host cell

Changing and blocking a ligand or its receptor can prevent infection.

Inability to make attachment proteins or adhesins renders microorganisms avirulent.

Bacterial pathogens attach to each other to form a biofilm. (e.g. dental plaque)

31
Q

Define Symptoms

A

Subjective characteristics of a disease that can be felt by the patient alone

e.g. pain, headache, dizziness and fatigue

32
Q

Define Signs

A

Objective manifestations of disease that can be observed or measured by others.

eg; swelling, rash, redness, and fever

33
Q

Define Syndrome

A

A group of symptoms and signs that collectively characterizes a particular disease or abnormal condition

e.g. (AIDS is characterized by malaise, losss of certain wbc’s, diarrhea, weight loss, pneumonia, etc)

34
Q

Define Asymptomatic (subclinical)

A

Lack symptoms but certain signs may still be detected

35
Q

What is etiology?

A

The study of the cause of disease.

36
Q

Koch’s postulates

Germ Theory of Disease

A

GTD: states that disease is caused by infections of pathogenic microorganisms.

37
Q

What are the five stages of Infectious diseases?

A
  1. Incubation Period: time between infection and occurence of the first symptoms or signs of disease
  2. Prodromal Period: a short time of generalized, mild symptoms that precedes illness.
  3. Illness: the most severe stage of an infectious disease. Signs and Syptoms most evident
  4. Decline: the body gradually returns to normal
  5. Convalescence: the patient recovers from the illness.
38
Q

What are portals of exit?

A

Pathogens leave hosts through portals of exit.

Many portals of exit are identical to portals of entry

Pathogens often exit hosts in materials that the body secretes or excreats (e.g. earwax, tears, nasal secretions, saliva, sputum and respiratory droplets)

39
Q

What is transmission?

What are three groups of transmission?

A

Transmission: from a reservoir or portal of exit to another host’s portal of entry

  1. Contact transmission: Direct, indirect, or droplet
  2. Vehicle Transmission: airborne, waterborne, or foodborne
  3. Vector Transmission: vectors are animals that transmit diseases from one host to another
  • Biological (Anopheles): also serve as hosts for multiplication of pathogen.
  • Mechanical (Musca): not required as hosts by the pathogens they transmit
40
Q

Classification of Disease

Terms of Disease

A
  • They can be classified by the body system they affect, into taxonomic categories, their longevity and severity, how they are spread to their host and the effects they have on population.

Terms:

Acute disease: develops rapidly but last a short time

**Chronic disease: ** develop slowly and are continual

subacute disease: between acute and chronic

Latent disese: pathogen remains inactive for a long time before becoming active

communicable: comes from another infected host

contagious: easily transmissible between hosts

41
Q

What is Epidemiology?

A

The study of where and when diseases occur and how they are transmitted with populations.

42
Q

Frequency of Disease

Incidence

Prevalence

Occurrence

A
  • Track occurrence of diseases using two measures
  • Incidence: number of new cases of a disease in a given area during a given period of time
  • Prevalence: number of total cases of a disease in a given area during a given period of time
  • Occurence: evaluated in terms of frequency and geographic distribution
43
Q

Name the terms for the occurence of disease and give definitions for each.

A

Endemic: A disease that normally occurs continually at a relatively stable incidence within a given population or geographical area.

Sporadic: when scattered cases occur within an area or population.

Epidemic: disease occurs at a greater frequency than is usual for an area or population.

Pandemic: When an epidemic occurs simultaneously on more than one continent.

44
Q

What are Nosocomial Infections?

Name the different types of Nosocomial infections and define.

A

Nosocomial Infections: Those that are acquired by patients or health care workers while they are in health care facilities, including hospitals, dental offices, nursing homes, and doctor’s waiting rooms.

Types:

  1. Exogenous: pathogen acquired from the health care environment
  2. Endogenous: Pathogen arises from normal microbiota due to factors within the health care setting
  3. Iatrogenic: results from modern medicual procedures
45
Q

Epidemiology and Public Health:

What are the agencies concerned with sharing information concerning disease?

What do the agencies do?

A

The agencies are: The united States Public Health Service and World Health Organization (WHO)

  • They work to limit disease transmission and monitor water and food safety. The public health agencies campaign to educate the public on healthful choices to limit disease.
46
Q

Virulence Factors:

Extracelular Enzymes

A
  • Secreted by the pathogen
  • dissolve structural chemicals in the body
  • Help pathogen maintain infection, invade and avoid body defenses

Hyaluronidase and collagenase

Coagulase and Kinase

47
Q

Virulence Factors:

Toxins

A
  • Chemicals that harm tissues or trigger host immune responses that cause damage
  • Toxemia refers to toxins in the bloodstream that are carried beyong the site of infection

Two types:

  1. Exotoxins: secreted from living cells
    * Cytotoxins, neurotoxins &enterotoxins
  2. Endotoxins: portion of outer cell wall membrane released upon cell death (Lipid A) of Gram negative bacteria
48
Q

Virulence Factors:

Antiphagocytic Factors

A

Factors prevent phgocytosis by the host’s phagocytic cells

  1. Bacterial Capsules
  • composed of chemicals not recognized as foreign
  • slippery; diffifcult for phagocytes to engulf bacteria
  1. Antiphagocytic Chemcials
  • Prevent fusion of lysosome and phgocytic vesicles
  • Leukocidins directly destroy phagocytic white blood cells.

Microbiology (6 decks)

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