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Micro 2 سو ساد > Chapter 1 > Flashcards

Chapter 1 Flashcards

1
Q

What is pathogenicity?

A

The ability to cause disease by overcoming the defenses of the host

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2
Q

What is a pathogen

A

A microorganism causes infection/disease

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3
Q

What is the virulence?

A

The degree or extent of pathogenicity

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4
Q

What is an infection?

A

The invasion or colonization of the body by pathogenic microorganisms

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5
Q

When does a disease occurs?

A

When the infection results in any chance in the normal state of the body to the abnormal

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6
Q

Name an example for an infection without a disease

A

AIDS

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7
Q

Identify inflammation

A

The localized tissues response to an injury or infection, often characterized by redness, swelling,pain, warmth, and pus

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8
Q

What does the ability of microorganisms to infect or cause disease depends on?

A

1 Interactions with the host defence mechanisms
2 the virulence factor
3 quantity/ number of invading microbes

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9
Q

Name the factors that determine the distribution and composition of normal microbes

A

Nutrients

Physical and chemical: temperature, pH, Oxygen, Co2, sunlight

Mechanical factors: chewing of the teeth and tongue, flow of saliva, flushing action of urine, mucus and cilia I’m the respiratory system

Defenses of the host,age, diet, health, disability, hygiene, stress

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10
Q

What is the relationship between normal and pathogenic microorganisms?

A

Microbial antagonism or competitive exclusion

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11
Q

What does microbial antagonism involves?

A

COMPETITION FOR:
nutrients

Producing harmful substances to the invading microbes (E.coli—-bacteriocin)

Affecting conditions such as PH

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12
Q

Give an example on bacteria that produce harmful substances to the invading microbes

A

E.coli:

It produces bacteriocins protein that inhibits the growth of salmonella and shigella

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13
Q

Give an example for a microorganism that grows after the PH or other conditions have been effected

A

After pH change Candida albicans (fungi) causes vaginitis

After normal bacteria elimination Clostridium difficile (gram positive anaerobic) causes fatal colitis

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14
Q

What are the the relationships between normal microbes and the host are? (Symbiosis) with examples

A

Commensalism: one benefits other doesn’t
Example staphylococcus epidermis (gram positive)

Mutualism: both benefits
Example E.coli ( gram -) synthesis vitamin K and B

Parasitism: one benefits while the other gets badly effected
Example: many disease causing bacteria

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15
Q

Identify opportunistic pathogens

A

They are pathogens that doesn’t cause a disease on normal states but do so on different environmental conditions

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16
Q

Give examples for opportunistic pathogens conditions with examples

A

Gaining access to other body sites such as the skin and mucous membranes
Example E.coli ( gram negative)

The host immunity is weakened by an infection
Example: Pneumocystis pneumonia (fungal) onlu happens after AIDS

Cooperation among microorganisms
Example in the mouth pathogens that causes periodontal disease and gingivitis have receptors for the oral streptococci

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17
Q

What are the exception to Koch’s postulates with examples

A

1 some have unique culture requirements
Example: Treponema pallidum that causes syphilis

  1. Signs and symptoms can be only exhibited in humans
  2. Some diseases have poorly defined etiologies
    Example: nephritis have several pathogens with the same signs and symptoms

4 some pathogens causes several diseases for example: mycobacterium tuberculosis causes diseases in the lungs, skin and bones
Streptococcus pyogenes can cause sore throat, scarlet fever and skin infections

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18
Q

What are the sources of microbes?

A

Another host or nonliving disease reservoir

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19
Q

What are the requirements for a successful pathogen

A

1 Surviving the passage
2 attach or penetrate the hosts tissues
3 withstand the host’s defenses
4 induce damage or malfunction to the tissues

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20
Q

What does symptoms mean

A

Changes in the body functions, such as pain ( can’t be observed or seen by an observer)

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21
Q

What does signs mean

A

Changes in the body that can be seen and measured such as swelling and fever

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22
Q

What does syndrome means

A

A group of symptoms or sings are evaluated together

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23
Q

What is a communicable disease

A

A disease that spreads from one host to another, directly or indirectly

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24
Q

Incidence vs prevalence

A

Incidence: probability of developing a disease, counting ONLY NEW cases, requires a follow up from individuals, doesn’t depend on the duration of the illness, preferred when studying the cause

Prevalence: probability of already having a disease, counts BOTH new and old, does not require a follow up, depends on the duration of the disease, preferred when estimating the population based burden of chronic disease

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25
Q

Classify disease by the frequency of occurrence with examples

A

1 sporadic diseases: occasionally
Example: typhoid fever

2 endemic disease: constantly present in a population
Example: common cold

3 epidemic: many people in a given area with a certain disease in a short period
Example: Influenza

4 pandemic: worldwide disease
Example p: COVID-19 حبيب الشعب

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26
Q

Classify diseases by severity or duration

A

1 Acute: rapid but last a short time
Example: tonsillitis

2 chronic disease: develops slowly and last a long period
Example: Lyme disease

3 subacute: between Acute and chronic

4 latent : remains inactive then becomes active to produce symptoms
Examples versilia zoster( virus) (خبيث زي انشالوتي)

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27
Q

What is the herd immunity

A

Many immune people are presein a community

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28
Q

What is a local infection

A

invading microorganisms are limited to a relatively small area
of the body. Such as boils and abscesses

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29
Q

What is a systematic infection

A

infection, microorganisms or their products are spread

throughout the body by the blood or lymph. Such as Measles and scarlet fever.

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30
Q

What is a focal infection

A

agents of a local infection enter a blood or lymphatic vessel
and spread to other specific parts of the body

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31
Q

Identify the following

Sepsis, septicemia, bacteremia, toxemia, viremia

A

Sepsis: a toxic inflammatory conditions arising from the spread of microbes

Septicemia: blood poisoning because of pathogens in the blood

Bacteremia: bacteria in the blood

Toxemia: toxins in the blood

Viremia: viruses in the blood

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32
Q

What are the differences between primary and secondary infections

A

Primary infection: an Acute infection that causes the main illness

Secondary infections: is an infection caused by an opportunistic pathogens because of the weakened immune system due to the primary infection
Example: any infection because of AIDS
Streptococcal bronchopneumonia after influenza

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33
Q

What is the subclinical (inapparent) infection

A

An infection that doesn’t cause any noticeable illness

Example: polio virus, AIDS, H.pylori, hepatitis A

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34
Q

Identify predisposing factors and name them with examples

A

They are the factors that makes the body more susceptible to a disease and may change the course of the disease

  1. Gender: females higher UTI than males males higher pneumonia and meningitis
  2. Genetic background: sickle cells patients are resistant to the malaria
  3. Climate and weather: higher respiratory disease increase during the winter

4 other: age, habits, lifestyle, chemotherapy, preexisting illness

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35
Q

What are the stages of disease developments

A 
1 Incubation
2 prodromal
3 period of illness
4 period of decline
5 period of convalescence
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36
Q

What is the incubation period and what does it depend on

A

It’s the time between the initial infection and the appearance of any signs or symptoms

It depends on:
1 virulence
2 number of microorganisms
3 resistance of the host

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37
Q

What kind of symptoms does the prodromal period have

A

Mild symptoms such as aches and malaise

38
Q

At what stage dies the illness become severe

A

Period of illness

39
Q

When does the patient becomes the most vulnerable to secondary infections

A

Period of decline

40
Q

What are the three main ways of disease transmission

A

1 contact
2 vehicle
3 vectors

41
Q

What are the types of contact transmission with examples

A

1 Direct contact (person to person)
Example: touching, kissing and sexual intercourse

2 indirect contact by fomite (nonliving objects
Examples: towels, tissues, bedding, cups, toys

3 droplets (less than 1M) 
Examples coughing, sneezing, laughing and talking
42
Q

Identify vehicle transmission and it’s types

A

Transmission by medium such as water, blood and other fluids

1 airborne: infection by droplets in nuclei in dust that TRAVELS MORE THAN 1 METER

2 Waterborne By water contaminated with sewage

3 Foodborne by poorly cooked food

43
Q

What is transmission by vectors and it’s types

A

Transmission by biological agents such as insects
The types
1 mechanical transmission such as insects feets

2 biological transmission such as biting

44
Q

What is nosocomial infections and name the top causes

A

It’s hospital related infections caused by
1 microorganisms in the hospital
2 The weakened status of the host
3 The chain transmission in the hospital

45
Q

What are the most frequent nosocomial infections

A

1 UTI 34%
2 skin infections 22%
3 surgical site 17%
4 LRTI 13%

46
Q

What are the contributing factors for emerging infectious diseases

A

1 evolution of a new strain such as V. Cholerae and E coli

2 inappropriate use of antibiotics which results in antibiotics resistance strains

3 changes in the weather

4 modern transportation systems such as airplanes ventilation system

5 ecological disaster such as coccidioidomycosis after 1994 California earthquake

6 insects and animals control measure
Exam, Lyme disease because of the rise in deer population

7 public health failure

8 diphtheria

47
Q

Identify epidemiology

A

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

48
Q

What are the epidemiology applications?

A

1) descriptive: Collection and analysis of data regarding
occurrence of disease

2) analytical: Comparison of a diseased group and a
healthy group

3) experimental: Study of a disease using controlled experiments
4) case reporting: Health care workers report specified disease to local, state, and national offices
5) nationally notifiable diseases: Physicians are required to report occurrence

49
Q

What are the differences between morbidity and mortality

A

Morbidity: incidence of a specific notifiable disease

Mortality: deaths from notifiable diseases

50
Q

What is the morbidity rate

A

number of people affected/total population in a given time period

51
Q

What is the mortality rate

A

number of deaths from a disease/total population in a given time

52
Q

What are the portals of entry

A

1) skin
2) mucous membranes
3) parenteral
4) preferred portal of entry such as swallowing and inhaling

53
Q

How does the microorganism enters the body through the skin?

A

1) Openings in the skin such as sweat glands
2) boring in the skin such as the larvae of the hookworms
3) grows on the keratin in the skin like fungi
4 infection of the mucous membrane itself such as conjunctiva

54
Q

Where is the mucous membrane membrane

A

1) respiratory tract
2) gastrointestinal tract
3) conjunctiva
4) genitourinary tract

55
Q

What is the most frequently traveled portal of entry?

A

Respiratory tract

56
Q

Name some diseases that uses the respiratory tract as an entry

A

the common cold, pneumonia, tuberculosis, influenza, and

measles

57
Q

Same some microbes that causes diseases the gastrointestinal tract

A

Poliomyelitis, hepatitis E & A, typhoid fever, amebic dysentery,
giardiasis, shigellosis (bacillary dysentery), listeriosis,
salmonellosis and cholera.

58
Q

Name some sexually transmitted infections (genitourinary tract entry)

A

HIV infection, genital warts, chlamydia,

herpes, syphilis, Borrelia and gonorrhea

59
Q

How does the microorganism enters using the parental route

A

Punctures, injections, bites, cuts, wounds,

surgery, and splitting of the skin or mucous
membrane due to swelling or drying can all establish parenteral routes

60
Q

Name same diseases that uses the parenteral route

A

HIV, the hepatitis viruses, and bacteria that cause tetanus, Lyme disease and gangrene

61
Q

What bacteria prefers the entry route through swallowing

A

Typhoid fever, (Salmonella typhi)

62
Q

What bacteria prefers the entry route through inhaling

A

Streptococci cause pneumonia

63
Q

Name some microorganisms with multiple entry routes

A

Yersinia pestis (gram negative) and Bacillus anthracis (gram negative)

64
Q

What are the different ID50s for Bacillus anthracis

A

oThrough the skin (cutaneous anthrax) is 10 to 50
endospores;
o Inhalation 10,000 to 20,000 endospores;
oGastrointestinal 250,000 to 1,000,000 endospores

65
Q

Give some examples for LD50

A

✓ Botulinum toxin in mice is 0.03 ng/kg; for
✓ Shiga toxin, 250 ng/kg; and
✓ Staphylococcal enterotoxin, 1350 ng/kg

66
Q

How do the bacterial pathogens penetrate the host defenses

A

1) capsules
2) cell wall components
3) enzyme
4) antigenic variation

67
Q

What are the capsules made of with some examples

A

Glycocalyx
Example: ➢Streptococcus pneumoniae, only capsulated Strains are virulent.
➢Klebsiella pneumoniae, a causative agent of bacterial
pneumonia

68
Q

Give some examples for cell wall components

A

A. M protein produce by Streptococcus pyogenes found on both the cell surface and fimbriae.

B. Fimbrae and Opa protein in Neisseria gonorrhoeae grows inside human epithelial cells and leukocytes.

C. The waxy lipid (mycolic acid) that makes up the cell wall of
Mycobacterium tuberculosis also increases virulence by
resisting digestion by phagocytes, and can even multiply inside phagocytes

69
Q

Give some examples for exoenzymes

A

a. Coagulases are bacterial enzymes that coagulate (clot) the fibrinogen in blood.
b. Bacterial kinases are bacterial enzymes that break down fibrin and thus digest clotsformedby the body to isolate the infection such as : fibrinolysin (streptokinase)

c. Hyaluronidase hydrolyzes hyaluronic acid,a type of polysaccharide that holds
together certain cells of the body,
particularly cells in connective tissue

70
Q

Give some examples for an antigenic variation

A
  1. N. gonorrhoeae has several copies of the Opa-encoding gene.
  2. Influenza virus
  3. Trypanosoma brucei gambiense the
    causative agent of African trypanosomiasis (sleeping sickness).
71
Q

How Bacterial Pathogens Damage Host Cells

A

(1) Using the host’s nutrients; Bacteria can obtain Iron by:
– Siderophores which are proteins secrete by microbes to obtain free iron from iron transport proteins lactoferrin,
transferrin, Hemoglobin and ferritin of the host.

(2) Causing direct damage in the immediate vicinity of the
invasion; by rupturing the cell during penetration or after multiplication

(3) Producing toxins, transported by blood and lymph,
(4) Inducing hypersensitivity reactions: immune response

72
Q

What are the two types of Bacterial toxins?

A

Exotoxins and endotoxins

73
Q

Where is the exotoxin produced?

A

Inside gram negative and positive bacteria as part of their growth and metabolism

74
Q

What is a toxoid

A

inactivated toxins by heat or by formaldehyde, iodine, or other chemicals,
• Cannot cause the disease .
• Used as vaccine to stimulate the body to produce antitoxins..

75
Q

What are the types of exotoxins

A 
1)  A-B Toxins : consist of two parts 
designated as A and B, A part is the 
active (enzyme) component, and the 
B part is the binding component (H. 
pylori)

2)Membrane-Disrupting Toxins
cause lysis of host cells by disrupting their plasma membranes (Staph and
Streptococcus).

3) Superantigens: are antigens that
provoke a very intense immune
response (S. aureus)

76
Q

How do endotoxins differ from exotoxins

A
  1. They are part of the outer portion of
    the cell wall of gram-negative bacteria
    lipopolysaccharides (LPS)
  2. Endotoxins are released when death or during bacterial multiplication
  3. Endotoxins stimulate T-lymphocytes to release cytokines in very high concentrations

4.All endotoxins produce the same signs and symptoms, regardless of the species of microorganism
Example: Chills, fever, weakness, generalized aches, and, in some cases, shock and even death

77
Q

What are the fungi’s pathogenic properties

A
  1. The production of toxins that provokes allergic responses and causes headaches and vomiting
  2. Secrete proteases that causes skin infections
    Example: Candida albicans and Trichophyton
  3. Producing capsules like Cryptococcus neoformans that causes meningitis
  4. causing ergotism

Producing toxins lime Aflatoxin (Aspergillus flavus) and mycotoxins like phalloidin and amanitin

78
Q

How does ergotism help in resistance to antifungals

A

by decreasing the synthesis

of receptors for these drugs

79
Q

Who produces ergot and what does it do

A

Claviceps purpurea
➢ can cause hallucinations
➢ can cause gangrene of the limbs

80
Q

What are the pathogenic properties of protozoa

A
  1. The presence of protozoa and their waste products often produces disease
  2. Some protozoa can evade host defenses and cause disease for very long periods of time by antigenic variation
81
Q

Give examples for a protozoa and their waste products that causes illness

A

❖ Plasmodium, the causative agent of malaria, invade host cells
(liver, RBCs) and reproduce within them, causing their
rupture and the release of hemozoin that causes the chill and fever symtoms.

❖ Toxoplasma attaches to macrophages and gains entry by phagocytosis.

❖ Giardia lamblia, the causative agent of giardiasis, attach to host cells by a sucking disc

82
Q

Name some protozoa with antigenic variation

A

❑Giardia, which causes diarrhea,
❑Trypanosoma, which causes African
trypanosomiasis (sleeping sickness)

83
Q

What is elephantiasis and what causes it

A

Wuchereria bancrofti

This parasite blocks
lymphatic circulation, leading to an accumulation oflymph and eventually causing grotesque swelling of the legs andother body parts.

84
Q

Name some examples for algae that produce neurotoxin

A

Alexandrium, (are important

medically) they produce a neurotoxin called saxitoxin.

85
Q

What are the portals of exists

A
  1. Respiratory: coughing and sneezing
  2. Gastrointestinal: (feces and saliva)
  3. Genitourinary
  4. Skin or wound
  5. Infected blood
86
Q

Give examples for diseases that uses the RESPIRATORY exist

A

tuberculosis, whooping cough, pneumonia, scarlet fever,
meningococcal meningitis, chickenpox, measles, mumps, smallpox, and
influenza

87
Q

Give examples for diseases that uses FECES as a exist

A

salmonellosis, cholera, typhoid fever, shigellosis, amebic dysentery, and
poliomyelitis, listeriosis

88
Q

Give examples for diseases that uses SALIVA as an exit

A

rabies, mumps, and infectious mononucleosis

89
Q

Name some diseases that uses URINE as a exist

A

typhoid fever and brucellosis,

90
Q

Name disease that uses the SKIN as a portal of exist

A

yaws, impetigo, ringworm,

herpes simplex, and warts

91
Q

Name some diseases that are transmitted by biting

A

yellowfever, plague , tularemia , and malaria.

92
Q

Name some diseases that uses needles and syringes

A

AIDS and hepatitis B

Micro 2 سو ساد (1 decks)

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