Park-Infectious Disease Flashcards

1
Q

Commensalism

A

-the colonizing bacteria acquire nutrition and the host gets neither benefit nor harm
-commensal bacteria in a human body (normal flora) are 10x more than human cells

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2
Q

Mutualism

A

-both the microorganism and the host derive benefits from the interaction

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3
Q

Infectious disease

A

the host sustains injury or pathologic damage

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4
Q

infectious agents

A

prions, viruses, bacteria, fungi, and parasites

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5
Q

Viruses

A

obligate intracellular pathogens

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6
Q

What are the components of. a virus

A

capsid (protein coats) and genome (RNA or DNA)

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7
Q

How does a virus develop an envelope?

A

they become enclosed in a envelope that is derived from the cytoplasmic membrane of the host cell

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8
Q

What can viruses cause

A

Lysis and death of the host cell during replication

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9
Q

Can a virus remain in the cell without causing disease?

A

Yes, a virus can remain in a latent, non replicating stage, for long periods without causing disease
-ex: varicella zoster virus (chicken pox at first and shingles later)

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10
Q

Can viruses cause cancer?

A

yes, an example is human papilomavirus (HPV) which can cause cervical cancer

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11
Q

Bacteria are___

A

prokaryotic

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12
Q

What are shapes of bacteria?

A

-spherical (diplococci, staphylococci, streptococci)
-elongated (bacilli)
-helical (sprilla [spirochetes])

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13
Q

Spirochetes

A

-anaerobic (bacteria)
-borrelia burgdorferi (Lyme disease)
-treponema pallidum (syphilis)

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14
Q

Mycoplasma

A

-bacteria that is much smaller than other bacteria
-have no cell wall which makes them resistant to cell-wall inhibiting antibiotics (such as penicillins)
-mycoplasma pneumoniae (pneumonia)

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15
Q

Rickettsiaceae

A

-obligate intracellular pathogen (bacteria)
-transmitted via arthropod vectors (mites, fleas, ticks, lice)
-rickettsia rickettsii (rocky mountain spotted fever)

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16
Q

chlamydiaceae

A

-obligate intracellular pathogen (bacteria)
-transmitted via person-to-person contact
-chlamydia trachomatous (sexually transmitted and can cause conjunctivitis in newborns)

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17
Q

Superficial mycoses (dermatophytosis)

A

-fungi
-ringworm, athletes foot (tinea pedia), and jock itch (tinea cruris)
-caused by dermatophytes whose infection is limited to the cooler cutaneous surfaces

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18
Q

Systemic mycoses

A

-serious fungal infections of deep tissue (rare)
-candidiasis (yeast infection)..opportunistic infection of candida albican, which is commensal flora in the skin, mucous membranes, and gastrointestinal tract
-aspergillosis…a lethal form of pneumonia caused by aspergillus, a common mold in people with lung diseases or immunocompromised patients

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19
Q

What helps protect the body from systemic mycoses

A

-intact immune mechanisms and competition for nutrients provided by the bacterial floral normally keep colonizing fungi in check

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20
Q

what can lead to opportunistic infections?

A

a disease or an antibiotic therapy can upset the balance and allow opportunistic infections to arise

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21
Q

Protozoa

A

-unicellular animals (parasite)
-plasmodium (malaria)…vector born (mosquito)
-entamoeba histolytica (amebic dysentery, or amoebiasis)…contaminated water and food
-giardia duodenalis (giardiasis)…contaminated water and food

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22
Q

Helminths

A

-wormlike parasites
-roundworms, tapeworms, flukes
-mainly in GI
-transmission primarily occurs through the ingestion of fertilized eggs (ova) or the penetration of infectious larval stages through the skin

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23
Q

Parasitic arthropods

A

-ectoparasites…mites (scabies), chiggers, lice (head, body, pubic), and fleas
-these may serve as vectors of other infectious diseases such as the bubonic plague which was spread by fleas

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24
Q

prions

A

-misfolded protein found in infectious material
-creutzfeld-jakob disease (associated with other neurodegenerative conditions) is human version of mad cow disease

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25
Q

epidemiology

A

the study of the patterns and determinants of health with the goal of controlling disease and health problems

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26
Q

incidence

A

the number of new cases of an infectious disease that occur within a defined population (such as per 100,000 people) over an established period of time (such as monthly, yearly, etc)

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27
Q

disease prevelence

A

the number of active cases at any given time in a population

28
Q

endemic

A

relatively stable incidence and prevalence in a particular geographic region

29
Q

epidemic

A

an abrupt and unexpected increase in the incidence of disease over endemic rates

30
Q

pandemic

A

the spread of disease beyond continental boundaries

31
Q

penetration

A

-any disruption may allow the invasion of pathogens, which normally cannot penetrate intact skin or mucous membranes
-ex. abrasions, burns, needles, insect and animal bites

32
Q

sexually transmitted infection

A

-transmitted by the exposure of the intact skin or membrane to pathogens
-ex. gonorrhea, syphilis, chlamydia, and genital herpes

33
Q

congenital infection

A

-infection of a child during gestation or birth from mother (vertical transmission)
-ex. toxoplasmosis, other (syphilis, varicella zoster, parvovirus B19), rubella, cytomegalovirus infection, and herpes simplex virus (TORCH infection) and HIV

34
Q

what are examples of direct contact transmission

A

-sexually transmitted infection
congenital infection

35
Q

TORCH infection

A

-Toxoplasmosis
-Others (syphilis, varicella zoster, parvovirus B19)
-Rubella
-Cytomegalovirus infection
-Herpes simplex virus

36
Q

Ingestion

A

-cholera, typhoid fever, amoebic dysentery, food poisoning, etc
-the low pH of the gastric acid acts as a barrier for many pathogens but some are resistant to low pH
-the normal bacterial flora of the bowel often compete with the pathogens

37
Q

What pathogens are resistant to low gastric pH?

A

-shigella
-giardia
-have differences (lower) infectious dose

38
Q

Inhalation

A

-bacterial pneumonia, meningitis, and tuberculosis
-viral infections such as measles, mumps, chickenpox, influenza, the common cold, and COVID
-the respiratory tract is equipped with multiple-tiered defense system (mucous membrane, coughing, antibodies and enzymes, phagocytosis, etc)

39
Q

What can weaken the defense system of the respiratory tract?

A

-smoking and diseases such as cystic fibrosis can impair the defense system

40
Q

Endogenous

A

opportunistic infection acquired from the hosts own microbial flora

41
Q

Exogenous

A

environment (water, food, soil, air)

42
Q

Person

A

direct contact

43
Q

Fomites

A

-inanimate objects contaminated with infected body fluids
-rhinovirus through shared toys
-HIV and HepB virus through shared syringes

44
Q

Animal (zoonoses)

A

-infectious diseases passed from other animal species to humans
-HIV, rabies. plague, influenza, SARS, MERS
-70% of emerging viral infections are zoonoses

45
Q

Vector

A

-biting arthropod
-Lyme disease by deer tick
-west nile virus by mosquitos

46
Q

nosocomial infection

A

healthcare associated infection (occurs in health care setting)

47
Q

What are types of places an infection can be acquired

A

-nosocomial
-community

48
Q

What are the stages of a disease?

A

-incubation period
-prodromal
-acute
-convalescent
-resolution

49
Q

what happens during the incubation period?

A

-active replication of a pathogen without recognizable symptoms

50
Q

What happens during the prodromal stage?

A

-initial appearance of symptoms
-mild fever, myalgia, headache, and fatigue (somewhat nonspecific)

51
Q

what happens during the acute stage?

A

-maximum impact of the infectious process
-inflammation and issue damage (more specific)

52
Q

What happens during the convalescent stage?

A

progressive elimination of the pathogen

53
Q

What happens during the resolution stage?

A

total elimination of a pathogen

54
Q

virulence factors

A

substances or products generated by infectious agents that enhance their ability to cause disease

55
Q

What are virulence factors?

A

-exotoxins
-endotoxins
-adhesion factor (adhesins)
-evasive factors
-invasive factors

56
Q

exotoxins

A

-proteins released by pathogenic bacteria
-inactive key cellular constituents (diphtheria toxin inhibits protein synthesis)
-many are superantigens inducing excessive and nonspecific inflammatory responses

57
Q

What can superantigens cause?

A

-induce excessive and nonspecific inflammatory responses
-bind to the (major histocompatibility complex) MHC of antigen-presenting cells and T cell receptors
-T cells are activated regardless of the antigen presented on MHC

58
Q

endotoxins

A

-lipids and polysaccharides that are not released (lipopolysaccharides)
-can induce clotting, bleeding, inflammation, hypotension, and fever (endotoxic shock)

59
Q

what are signs and symptoms of endotoxic shock?

A

-clotting
-bleeding
-inflammation
-hypotension
-fever

60
Q

Adhesion factors (adhesins)

A

-bind to macromolecules on the surface of host cells
-adhesion is critical for the colonization of the pathogens
-some pathogens form a mucous layer (slime)

61
Q

evasive factors

A

-inactivate the hosts immune system
-leukocidins form pores in the cell membrane of neutrophils and macrophages
-some pathogens survive and reproduce within phagocytes after phagocytosis by neutralizing lysosomal contents with evasive factors

62
Q

invasive factors

A

-facilitate the penetration of anatomic barriers
-pseudomonas aeruginosa collagenase breaks skin

63
Q

Anthelminthics are drugs to treat infections by___
A. viruses
B. bacteria
C. fungi
D. protozoa
E. wormlike parasites

A

E. wormlike parasites

64
Q

Which of the following pathogens is a protozoon (unicellular animal) For your information, the name of the disease caused by each pathogen is shown in parentheses.
A. Candida albican (candidiasis)
B. rickettsia rickettsia (rocky mountain spotted fever)
C. mycoplasma peumoniae (pneumonia)
D. plasmodium falciparum (malaria)
E. borrelia burgdorferi (Lyme disease)

A

D. plasmodium falciparum (malaria)

65
Q

Tetanus toxin induces paralysis in the host cell by blocking neurotransmitter release. What type of virulence factor is tetanus toxin?
A. endotoxin
B. exotoxin
C. evasion factor
D. adhesion factor
E. invasion factor

A

B. exotoxin

66
Q

Which of the following infections is not a classical example of congenital infections (Hint: These infections are frequently called TORCH infections)
A. toxoplasmosis
B. rubella
C. cytomegalovirus infection
D. herpes simplex virus infection
E. shigella

A

E. shigella

67
Q

Which of the following is an example of infection through fomites?
A. a student has contracted COVID after talking to an infected friend
B. a man contracted syphilis after a sexual contact
C. a hotel guest contracted the flu after touching a contaminated button in an elevator
D. a woman has contracted lyme disease after a tick bite
E. a hiker has contracted amoebic dysentery after drinking water from a lake

A

C. a hotel guest contracted the flu after touching a contaminated button in an elevator