Chapter 14 Flashcards

Principles of Disease and Epidemiology

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1
Q

Pathology

A

Scientific study of disease, concerning the cause of disease and the structural and functional changes brought about by disease and with their final effects on the body

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2
Q

Etiology

A

The study of the cause of disease

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3
Q

Pathogenesis

A

The manner in which disease develops

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4
Q

Infection

A

The invasion or colonization of the body by pathogenic microorganisms pr the presence of a microorganism in part of the body where it is not normally found. It can exist in the absence of detectable disease; no symptoms.

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5
Q

Disease

A

Occurs when an infection results in any change from a state of health. It’s an abnormal state. The body cannot perform all it’s normal functions. Part or all of the body is not properly adjusted.

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6
Q

Human Microbiome Project

A

Began in 2007 to analyze microbial communities called microbiomes that live on and in the body. With a goal of trying to determine the relationship between changes in human microbiome and human health and disease.

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7
Q

Normal microbiota

A

Normal flora; Microorganisms that establish more or less permanent residents (colonize) but do not produce disease under normal conditions.

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8
Q

Transient microbiota

A

Microorganisms that may be present for several days, weeks, or months and then disappear. They are not found throughout the entire human body but are localized in certain regions.

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9
Q

What are the factors that determine the distribution and composition of normal microbiota

A

Nutrients, physical and chemical factors, defenses of the host, and mechanical factors.

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10
Q

How do nutrients affect normal microbiota and where do they come from

A

Microbes can colonize only those body sites that can supply the appropriate nutrients. These nutrients maybe derived from secretory and excretory products of cells, substances in body fluids, dead cells, and foods in the gastrointestinal tract.

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11
Q

What are the physical and chemical factors that affect the growth of microbes and result in normal microbiota

A

Temperature, pH, available oxygen and carbon dioxide, salinity, and sunlight

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12
Q

What are mechanical forces that the human body uses against microbes

A

Mechanical forces such as chewing, the flow of saliva and digestive secretions, the flushing of urine during urination.

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13
Q

How does the human body’s protect itself against microbes

A

The human body has a variety of molecules and activated cells that kill microbes, inhibit their growth, prevent their adhesion to host cell surfaces and neutralize toxins that microbes produce.

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14
Q

Microbial antagonism

A

Also known as competitive exclusion. A manner in which normal microbiota can benefit the host by preventing the overgrowth of harmful micro organisms, involving competition among microbes.

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15
Q

How does microbial antagonism protect the host against colonization by potentially pathogenic microbes

A

Normal microbiota compete with pathogenic microbes for nutrients and they produce substances harmful to the invading microbes and affect conditions such as pH and available oxygen.

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16
Q

What is the relationship between the normal micro biota and the host called and what does it mean

A

Symbiosis. At least one organism is dependent on the other

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17
Q

Commenalism

A

Symbiotic relationship in which one of the organisms benefits and the other is unaffected

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18
Q

Mutualism

A

A type of symbiosis that benefits both organisms

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19
Q

Parasitism

A

A type of symbiosis where one organism benefits by deriving nutrients at the expense of the other.

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20
Q

How can a mutualistic organism become harmful? What’s an example

A

As long as it remains in it’s normal environment it is not infectious. Once it gets access to bbn other body sites it can become infectious. Example: E. coli in the large intestine is normal, if it gets into the urinary tract it can become infectious

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21
Q

Opportunistic pathogens

A

Microbes that do not ordinarily cause disease in their normal habitat in a healthy person but may do so in a different environment. Example: E. coli

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22
Q

Example of commensalism

A

Staphylococcus epidermidis on the skin

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23
Q

Example of mutualism, how

A

E coli in the large intestine. They synthesize Vit K and some B vit that are absorbed into the bloodstream and used by cells in the body. In exchange the large intestine provides nutrients used by baceria that allows for their survival

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24
Q

Other than competition among microbes, what is another factor in the cause of disease

A

Cooperation among microbes. Example: pathogens that cause periodontal disease and gingivitis have been found to have receptors, not for teeth, but for oral streptococci that colonize the teeth

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25
Q

Noninfectious diseases

A

Diseases that are not caused by microorganisms, such as inherited and degenerative diseases

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26
Q

Infectious diseases

A

Disease caused by microorganisms

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27
Q

Where is a key criterion in the validity of any scientific proof

A

That the experimental results be repeatable

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28
Q

In summary, what are Koch’s postulates

A
  1. The same pathogen must be present in every case of the disease
  2. The pathogen must be isolated from the diseased host and grown in pure culture
  3. The pathogen from the pure culture must cause a disease when it is inoculated into a healthy susceptible laboratory animal
  4. The pathogen must be isolated from the inoculated animal and it must be shown to be the original organism
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29
Q

What are some exceptions to Koch’s postulates

A

They are modified to establish etiologies of diseases caused by viruses and some bacteria which cannot be grown on artificial media

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30
Q

What are some diseases that cannot be verified by Koch’s postulates

A

▪︎Tetanus have unequivocal signs and symptoms
▪︎Pneumonia and nephritis may be caused by a variety of microbes
▪︎Certain pathogens, such as HIV, cause disease in humans only
▪︎Some pathogens, such as S. pyrogenes, cause several different diseases

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31
Q

Symptoms

A

Subjective changes in body function such as pain and malaise

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32
Q

Signs

A

Objective changes that can be observed and measured such as swelling, fever, and paralysis

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33
Q

Syndrome

A

A specific group of symptoms and signs that accompany a particular disease

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34
Q

Communicable disease

A

Any disease that spreads from one host to another, either directly or in directly

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35
Q

Examples of communicable diseases

A

Chicken pox, measles, general herpes, typhoid fever, tuberculosis

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36
Q

Contagious diseases

A

Diseases that are easily spread from one person to another

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37
Q

Examples of contagious diseases

A

Chicken pox and measles

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38
Q

Non communicable disease

A

Diseases caused by microorganisms that normally inhabit the body and only occasionly produce disease, and is not spread from one person to another. Some only cause disease when they reside on the body and somehow get inside the body.

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39
Q

Incidence

A

The number of people in a population who develop a disease during a particular time period

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40
Q

Prevalence

A

The number of people in a population who develop a disease at a specified time regardless of when it 1st appeared. This includes both old and new cases.

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41
Q

What is a good indicator of the spread of disease

A

Incidence

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42
Q

Sporadic disease

A

A disease that occurs only occasion only

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43
Q

Endemic disease

A

A disease constantly present in a population

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44
Q

Epidemic disease

A

A disease acquired in a given area in a relatively short period

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45
Q

Pandemic

A

A disease occurring in the world wide

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46
Q

Acute disease

A

A disease that develops rapidly but lasts only a short period of time

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47
Q

Chronic disease

A

A disease that develop slowly and the body’s reaction May be less severe but the disease is likely to continue to recur for long periods

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48
Q

Sub acute disease

A

A disease that it is intermediate between acute and chronic

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49
Q

Latent disease

A

A disease in which a causative agent remains inactive for a time but then becomes active and produces symptoms of the disease

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50
Q

Herd immunity

A

When many Immune people are present in a community

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51
Q

Local infection

A

An infection in which the invading micro organisms are limited to a relatively small area of the body

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52
Q

Example of local infection

A

Boils and abscesses

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53
Q

Systemic infection

A

An infection in which micro organisms or their products are spread throughout the body by the blood or d lymph

54
Q

Example of systemic infection

A

Measles

55
Q

Focal infection

A

A confined infection to specific areas of the body that results from a local infection that entered the blood or lymphatic vessel and spread to those parts of the body

56
Q

Where do focal infections usually arise from

A

Teeth, tonsils, or sinuses

57
Q

Sepsis

A

A toxic inflammatory condition arising from the spread of my grobes especially bacteria or their toxins from a focus of infection

58
Q

Septicemia

A

Blood poisoning, A systemic infection arising from the multiplication of pathogens in the blood

59
Q

Example of septicemia

A

Sepsis

60
Q

Bacteremia

A

Presence of bacteria in the blood

61
Q

Toxemia

A

Presence of toxins in the blood

62
Q

Example of toxemia

A

Toxins from the infection ction tetanus

63
Q

Viremia

A

Presence of viruses in blood

64
Q

Primary infection

A

An acute infection that causes initial illness

65
Q

Secondary infection

A

An infection caused by an opportunistic pathogen after the primary infection has weakened the body’s defenses

66
Q

Common secondary infections

A

Occur of the skin and respiratory tract

67
Q

Which would be more dangerous, a primary infection or secondary infection of the skin or respiratory tract

A

Secondary infection

68
Q

Subclinical infection

A

AKA Inapparent infection, one that does not cause any noticeable illness

69
Q

Predisposing factor

A

A factor that affects the occurrence of disease and makes the body more susceptible to a disease and may alter the course of the disease

70
Q

Examples of predisposing factors

A

Gender, genetic background, climate and weather, inadequate nutrition, fatigue, age, environment, habitats, lifestyle, occupation, pre existing illness, chemotherapy, emotional disturbances

71
Q

Sequence of development of disease

A
  1. Incubation period
  2. Prodromal period
  3. Period of illness
  4. Period of decline
  5. Period of convalescence
72
Q

Incubation period

A

The interval between the initial infection and the 1st appearance of any signs or symptoms.

73
Q

The time of incubation depends on what

A

Specific microorganism involved, its virulence, the number of infecting microorganisms and the resistance of the host

74
Q

Prodromal period

A

A relatively short. That follows the period of incubation. It is characterized by early, mild symptoms of disease, such as general aches and malaise

75
Q

Period of illness

A

The disease’s most severe in this stage. The person exhibits overt signs and symptoms of disease such as fever, chills, muscle pain, sensitivity to light, soar throat, lymoh node enlargement, and gastrointestinal disturbances. The number of white blood cells may increase or decrease. The patients immune response and other r defense mechanisms overcome the pathogen and the period of illness ends. If the disease is not successfully overcome, the patient dies during this period.

76
Q

Period of decline

A

During this time the signs and symptoms go away. It can take from less than 24 hours to several days. The patient is vulnerable to secondary infections.

77
Q

Period of convalescence

A

The person regains strength and the body returns to its pre disease. Recovery has occurred.

78
Q

During which development of disease period can one serve as a reservoir and spread infection to other people

A

Incubation, period of illness, and convalescence

79
Q

Reservoir of infection

A

A source that can be either living or an inanimate object that provides a pathogen with adequate conditions for survival and multiplication and an opportunity for transmission

80
Q

What are the different types of reservoirs

A

Human, animal, and non living

81
Q

Human reservoir

A

Many people harbor pathogens and transmit them directly or indirectly to others. This can occur when people have signs and symptoms of disease or they can be carriers

82
Q

When are people considered carriers of a disease

A

During the latent peroid, during incubation, or during the convalescent period.

83
Q

Animal reservoirs

A

Both wild and domestic animals are living reservoirs that can carry microorganisms that can cause human disease

84
Q

Zoonoses

A

Diseases that occur primarily in wild and domestic animals and can be transmitted to humans

85
Q

Examples of zoonoses

A

Rabies and Lyme disease

86
Q

How are zoonoses transmitted to humans

A

Direct contact with infected animals, By direct contact with domestic pet waste, By contamination of food and water, By air from contaminated hides, furs or feathers, By consuming infected animal products, By insect vectors

87
Q

2 major Nonliving reservoirs

A

The 2 major non living reservoirs of infectious disease or soil and water

88
Q

What microbes does soil harbor

A

Fungi and bacteria

89
Q

How is water usually contaminated

A

By the faces of humans and other animals, It’s fully responsible for gastrointestinal disease

90
Q

What are other non living reservoirs

A

Improperly prepared are stored food

91
Q

What are the different ways disease can be transmitted

A

Contact transmission, Vehicle transmission, Vectors

92
Q

Contact transmission

A

The spread of an agent of disease by direct contact, indirect contact, droplet transmission

93
Q

Direct contact

A

Person to person transmission by physical contact between its source and a susceptible host

94
Q

What diseases can be transmitted through direct contact

A

Viral respiratory tract diseases, staphylococcal infections, hepatitis A, measles, scarlet fever, and STD’s. Pathogens from animals to humans can occur by direct contact as well.

95
Q

Indirect contact transmission

A

Occurs when the agent of disease is transmitted from its reservoir to a susceptible hosts by means of a nonliving object

96
Q

Term for a nonliving object involved in the spread of infection

A

Formite; tissues, eating utensils, towels, money contaminated syringes

97
Q

Droplet transmission

A

Microbes that are spread in droplet nuclei that trouble only short distances. These droplets or discharge into the air by coughing, sneezing, laughing, or talking and travel less than one meter from reservoir to the host.

98
Q

Vehicle transmission

A

The transmission of a disease by a medium such as water, food, air, body fluids, drugs, intravenous fluids.

99
Q

Most important group of disease vectors

A

Arthropods are the most important group of disease vectors, animals that carry pathogens from one host to another

100
Q

What are the to general method arthropods transmit disease

A

Mechanical and biological transmission

101
Q

What is mechanical transmission

A

It is the passive transport of pathogens on the insects feet or other body parts

102
Q

Biochemical transmission

A

An active process of transmission in which the arthropod bites an infected person or animal and ingest some of the infected blood. The pathogen reproduces inside the vector and this increases the number of pathogens which increases the possibility that they will transmit to another host.

103
Q

Nosocomial infection

A

An infection that is acquired as a result of a hospital stay or acquired in another healthcare facility

104
Q

Which facilities cause health care associated infections

A

Same day surgical centers, ambulatory outpatient healthcare clinics, nursing homes, rehab homes,1 and home health care environments

105
Q

What are the 3 factors that are involved in a nosocomial infection

A
  1. Microorganisms in the hospital environment
  2. The compromised status of the host
  3. The chain of transmission in the hospital
106
Q

Compromised host

A

One whose resistance to infection is impaired by disease, therapy, or burns

107
Q

What are the 2 principal conditions that can compromise a host

A

Broken skin or mucous membrane and a suppressed immune system

108
Q

What is the 1st line of defense of a host

A

The skin

109
Q

What can break the 1st line of defense and make a person more susceptible to disease

A

Burns, surgical wounds, trauma, injections, invasive diagnostic procedures, ventilators, intravenous therapy, urinary catheter

110
Q

Other than the 1st line of defense what is another thing that can increase a hosts susceptibility to infection

A

Things that can alter breathing and contribute to pneumonia

111
Q

Principal routes of transmission in the hospital

A
  1. Direct contact transmission from hospital staff to patient and from patient to patient
  2. Indirect contact transmission through formites and the hospital’s ventilation system
112
Q

What is the single most important means of preventing the spread of infection

A

Handwashing

113
Q

Emerging infectious diseases

A

Diseases that are new or changing, showing an increase in incidence in the recent past, or potential to increase in the near future

114
Q

What percent of emerging infections are zoonotic

A

75%

115
Q

What factors contribute to the emergence of new infectious diseases

A
  1. New strains
  2. New serovar: evolution
  3. Unwarranted use of antibiotics and pesticides
  4. Global warming/changes in weather patterns
  5. Spread of disease to new geographic areas by modern transportation
  6. Unrecognized infections appearing in individuals were an environment is undergoing ecological changes
  7. Animal control or the lack of
  8. Failures and public health measures such as lack of vaccinations
116
Q

How did the CDC and NIH and the WHO develop plans to address issues related to emerging infectious diseases

A
  1. Detect, investigate and monitor infectious pathogens
  2. Expand basic and applied research on ecological, environmental factors, microbial changes, adaptations, host interactions that influence EIDs
  3. Enhance communication of public health information and prompt implementation of prevention strategies
  4. Establish plans to monitor and control EIDs worldwide
117
Q

Epidemiology

A

The science that studies when and where diseases occur and how they are transmitted in populations

118
Q

What is an epiemiologists job

A

To study the etiology of disease and identify other possibly important factors in patterns concerning the people affected, how to control it, how effectively is it being controlled, provide data to help evaluate and plan the overall health care for a community

119
Q

What are the 3 basic types of an investigation when analyzing occurrence of disease

A
  1. Descriptive epidemiology
  2. Analytical epidemiology
  3. Experimental epidemiology
120
Q

Descriptive epidemiology

A

Involves the collection of data that describes how the disease developed. This includes information about those that were affected, and the place and period of time it occurred.

121
Q

Descriptive epidemiology

A

Involves the collection of data that describes how the disease developed. This includes information about those that were affected, and the place and period of time it occurred.

122
Q

Analytical epidemiology

A

evaluates a disease to determine why it occurred.

123
Q

What are the 2 types of analytical epidemiology

A

The case control method and the cohort method

124
Q

What is the case control method

A

With the case control method, epidemiologist compare a group of people with the disease and a group of people free from the disease. These groups are similar in age, sex, socioeconomic status, and location. They then look at factors that may have contributed to the incidence of the disease. These might include genetic, environmental, and nutritional factors.

125
Q

What is the cohort method

A

With the cohort method, two populations are examined. They include one that has had contact with the agent and another that has not.

126
Q

Experimenter epidemiology

A

an experiment that is done in regard to a specific disease. A hypothesis is made, and an experiment is done with a group of people. They might possibly test a drug to measure its effectiveness.

127
Q

What is case reporting

A

A procedure that requires health care workers to report specified diseases to local, state, and national health officials

128
Q

CDC

A

The centers for disease control and prevention is a branch of the United States public health service and a central source of epidemiological information

129
Q

Morbidity

A

The incidence if a specific notifiable disease

130
Q

Mortality

A

Number of deaths from a specific specific disease

131
Q

Isolation

A

the act of separating a sick individual with a contagious disease from healthy individuals without that contagious disease

132
Q

Quarantine

A

A period of isolation decreed to control the spread of infectious disease. These people may have been exposed to a disease and do not know it, or they may have the disease but do not show symptoms.