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Micro Exams > Exam 4 > Flashcards

Exam 4 Flashcards

1
Q

fungal disease: community-acquired

A

infections caused by environmental pathogens

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2
Q

fungal disease: hospital-associated

A

infections caused by fungal pathogens in clinical settings

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3
Q

fungal disease: opportunistic infections

A

caused by low-virulence species infecting already-weakened individuals

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4
Q

Dermatophytes

A

Unique group of fungi that infect keratinous tissue and are able to invade the hair, skin, and nails of a living host
(a) Athlete’s foot. (b) Ringworm on a child’s face and (c) on an adult index finger.

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5
Q

Dermatophytes: Genus Examples

A
  • Microsporum
  • Epidermophyton
  • Trichophyton
    Causes: Ringworm, athlete’s foot, jock itch, fungal nail bed infections
    among others
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6
Q

Cryptococcosis

A

A pulmonary or disseminated infection acquired by inhalation of soil contaminated with the encapsulated yeasts.

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7
Q

Cryptococcus neoformans

A
  • Infection commonly associated with
    immunosuppressive
  • Meningitis and meningoencephalitis
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8
Q

Cryptococcus gatti

A
  • Infections NOT associated with
    immunosuppression
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9
Q

Aspergillosis

A

An infection caused by Aspergillus species, a common mold

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10
Q

Aspergillus species

A
  • Ubiquitous in the environment
  • Mainly in immunocompromised individuals
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11
Q

Aspergillus fumigatus

A

most prevalent and is largely responsible for invasive aspergillosis with a very high mortality rate

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12
Q

Aspergillus flavus

A

synthesizes a poison called aflatoxin,
potentially lethal to animals who eat contaminated grain
- can lead to acute hepatitis, immunosuppression, hepatocellular
carcinoma, and neutropenia (LIVER ISSUES)

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13
Q

Ophiocordyceps unilateralis

A

“Zombie-ant fungus”
- Insect-pathogenic fungus
- Predominantly in tropical
forest ecosystems
- Genus examples: Other members of Cordyceps and Ophiocordyceps also
parasitize insects

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14
Q

Histoplasmosis

A

“Ohio Valley Fever”

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15
Q

“Ohio Valley Fever”

A

Caused by the fungus Histoplasma capsulatum
- * Not contagious so it can’t be spread from person to person
* Primarily affects lungs
→ symptoms similar to pneumonia
- Naturally found in soil, often associated with bat or bird droppings
- In Latin America and the Caribbean, histoplasmosis is one of the most
common infections among people living with HIV
- 75% of adults who
live in areas where H. capsulatum is common have been infected before

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15
Q

Candidiasis

A

A fungal infection typically on the skin or mucous membranes caused by a yeast – Candida
- Residential flora
* Found on skin, mouth, throat, gut, and vagina

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15
Q

Ergot: a group of fungi in the genus Claviceps

A

Most commonly Claviceps purpurea

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15
Q

Candida albicans (most common)

A

Opportunistic pathogen
* Thrush, vaginal yeast infection,
cutaneous candidiasis

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16
Q

Ergotism

A

Poisoning produced by eating food affected by ergot
- gangrene of the fingers and toes
- Also known as: Saint Anthony’s Fire,
ergotoxicosis, or ergot poisoning
- Infects rye and other cereals

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17
Q

Aflatoxins are produced by?

A

Aspergillus

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18
Q

Which of the following structures would NOT be associated with fungi?

A

chloroplasts

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19
Q

Ergosterol synthesis is often the target of anti-fungal drugs T or F

A

True

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20
Q

Claviceps can cause several effects in humans and other animals, such as
hallucinations and gangrene. It is usually ingested by contaminated?

A

Grain

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21
Q

Which of the following fungi are the cause of ergotism?

A

Claviceps

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22
Q

Algae

A

A group of photosynthetic organisms
- Widespread in both fresh and marine waters
- Contribute significantly to oxygen content of the atmosphere through photosynthesis

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23
Q

Algae what organelles?

A

chloroplasts

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24
Q

Diatoms

A

One of the most prevalent groups on Earth are the single-celled diatoms

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25
Q

Cell wall of diatoms?

A

contains silica

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26
Q

Diatoms high diversity

A

High diversity is useful in forensics in analyses of bodies of water

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27
Q

Forensic Limnology

A

the study of freshwater ecology for the presence of diatoms (particularly) in order to solve forensic and medical cases

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28
Q

Diatoms with silica

A

Cosmetic products, Used as an insecticide, Structural Materials

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29
Q

Prototheca: infections algae

A
  • associated with skin and subcutaneous infections in humans and animals
  • infection rare, most of the time just toxic
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30
Q

Prototheca

A
  • Only recognized as human and animal pathogens in the 1960s
  • First human outbreak in 2018
  • No effective drugs
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31
Q

Dinoflagellates (made toxin)

A

Can cause algae blooms
- Red tides – marine species
- Intertidal animals feed → accumulate toxins given off
by algae

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32
Q

Paralytic shellfish poisoning (causes)

A

caused by eating exposed clams or other invertebrates

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33
Q

Ciguatera (toxin)

A

a serious intoxication caused by algal toxins that have accumulated in fish

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34
Q

Protozoa

A

“first animals”
- 12,000 species of single-celled creatures
- Most are harmless, free-living inhabitants of water and soil
- few species are pathogens

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35
Q

Protozoan Form and Function

A
  • Single cells containing all of the major eukaryotic organelles
  • Cytoplasm divided into two parts: ectoplasm and endoplasm
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36
Q

Ectoplasm

A

clear outer layer involved in locomotion, feeding, and protection

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37
Q

Endoplasm

A

granular inner region housing the nucleus, mitochondria, and food and contractile vacuoles

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38
Q

Protozoan Form and Function cont.

A
  • Some organelles act as a primitive nervous system to coordinate movement
  • Can move through fluids by means of pseudopods (“false feet”)
  • Cell membrane
  • Cell shape can remain constant (as in most ciliates), or change constantly (as in amoebas)
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39
Q

Protozoa Nutritional and Habitat Range

A
  • Heterotrophic
  • Free-living species scavenge dead plant or animal debris or graze on bacteria and algae
  • Some have special feeding structures, such as oral grooves
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40
Q

Nutritional and Habitat Range cont.

A

Main limiting factor is availability of moisture
- Predominant habitats are fresh and marine water, soil, plants, and
animals
- can survive in non moist areas but don’t always grow

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41
Q

Life Cycles: Protozoa

A

Trophozoite (all can be)
Cyst (some)

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42
Q

Trophozoite

A

motile feeding stage requiring
ample food and moisture to stay active

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43
Q

Cyst

A

Dormant, resting stage when conditions in the environment become unfavorable
* Resistant to heat, drying, and chemicals
* Can be dispersed by air currents
* Important factor in the spread of disease

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44
Q

Alternating?

A

Many alternate between the trophozoite and cyst
stage, depending on the habitat

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45
Q

Reproduction: Protozoa

A

All protozoa reproduce by relatively
simple, asexual mitotic cell division
or multiple fission

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46
Q

Sexual reproduction also occurs in most protozoa (they want to)

A
  • Ciliates participate in conjugation in
    which two cells fuse and exchange
    micronuclei
  • Results in new and different genetic
    combinations → can be advantageous in evolution
    -2 organisms connecting
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47
Q

Trichomoniasis
(causative agent Trichomonas vaginalis)

A

Common STI
- Antibiotic treatment is usually very successful
- Trich can increase the risk of getting or spreading other STIs
Men:
mostly asymptomatic
Women:
symptomatic
- survive for several hours on moist
surfaces and up to a day in urine or
semen
- contaminated fomites,
such as toilet seats, sauna benches, and towels

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48
Q

African Trypanosomiasis
(Sleeping Sickness)

A

Vector: tsetse fly
- Drowsiness, Insomnia, Sleepiness
- painful nodule at site of fly
bite

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49
Q

causative agent: Trypanosoma brucei

A

Vector: tsetse fly
- Treatment should be early
- enters lymphatic system

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50
Q

Chagas Disease (American Trypanosomiasis)

A

causative agent Trypanosoma cruzi

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51
Q

Chagas Disease (American Trypanosomiasis) cont.

A
  • Latin America
  • Vector: Triatomine bugs, known
    as ‘kissing bugs’
  • transmitted by feces of the insect (bites face)
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52
Q

Chagas Disease (American Trypanosomiasis): acute and chronic

A
  • acute: maybe asymptomatic or
    mild like fever, malaise
  • followed by remission – no
    symptoms for many years
  • chronic: includes digestive
    problems and heart failure
  • treat early
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53
Q

Giardia causative agent

A

Giardia intestinalis

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54
Q

Giardia

A

Most frequently diagnosed intestinal parasitic disease in the United States

  • Transmitted via contaminated sources or fecal-oral route (hands or fomites)
  • The thick-walled cysts are resistant to chlorine
  • most outbreaks have been associated with water systems that
    used only chlorination as a means of water purification
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55
Q

Giardia

A
  • form cyst
  • Cysts are hardy and can survive several months in cold water
  • The chances of people getting a Giardia infection from dogs or cats are small
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56
Q

Amoebic dysentery - Amebiasis causative agent

A

Entamoeba histolytica

57
Q

Amoebic dysentery - Amebiasis

A
  • untreated sewage is allowed to enter surface waters
  • Parasite only lives in humans and is passed via feces
  • Commonly asymptomatic (9/10)
  • no vaccine, but treated with drugs
  • common for reinfection because it does not confer immune memory
58
Q

Primary amebic meningoencephalitis (PAM) causative agent

A

“Brain-eating Amoeba” →Naegleria fowleri
- Warm fresh water and soil
- Enters the body through the nose → travels to the brain → extensive hemorrhage and brain damage
- Otherwise….nearly always fatal (>97% mortality rate)

59
Q

Acanthamoeba
keratitis

A

Rare, but severe infection of the eye (cornea)
- Can result in permanent visual impairment or blindness
- More common in people who wear contact lenses

60
Q

Acanthamoeba
keratitis causative agent

A

Acanthamoeba → free-living ameba
* Found in bodies of water, soil, and air

61
Q

Balantidiasis causative agent

A

Balantidium coli

62
Q

Balantidiasis

A

The only ciliate known to be capable of infecting humans
- Often associated with swine → primary reservoir host
* Humans can also be reservoirs, and other potential animal hosts include rodents and nonhuman primates
- Cysts are the stage responsible for transmission
- Mostly asymptomatic, sometimes a perforated colon

63
Q

Toxoplasmosis causative agent

A

Toxoplasma gondii

64
Q

Toxoplasmosis

A

Cat litter box disease; contaminated food and water
- Severe infections more likely in newborn
- 1-5 days to become infectious

65
Q

Cryptosporidiosis “Crypto” disease (commonly confused)

A

Leading cause of waterborne disease among humans in the United States
- Can survive long periods of time outside host
* Protected by an outer shell
* Tolerant to chlorine disinfection
- Water is the most common method of transmission
-

66
Q

Leading cause for human infection

A

Cryptosporidium parvum and Cryptosporidium hominis

  • leading cause of pediatric
    diarrhea worldwide, and it is responsible for nearly 9% of fatalities due to infectious disease in children
67
Q

Malaria causative agent

A

Plasmodium
- 5 species that cause malaria in humans
* P. falciparum and P. vivax most threatening

68
Q

Malaria

A

Vector: female Anopheles mosquitoes
* Resistance to antimalarial medicines is a recurring problem
* Can be controlled by eliminating mosquitoes

69
Q

Flagellates that infect the genital tract?

A

Trichomonas vaginalis

70
Q

Which of the following is the same for both Trypanosoma cruzi and Trypanosoma brucei and the infectious diseases they cause?

A

Importance of early diagnosis
and treatment

71
Q

Which of the following is thought to be one of the agents of frequent cause of non-bacterial diarrhea in
North America?

A

Giardia

72
Q

The Helminths

A

tapeworms, flukes, roundworms
- Adult specimens are usually large enough to be seen with the naked eye
- microscope for eggs/larvae
- many live free in soil and water
~50 species cause disease in humans
- Disease-causing helminths spend part of their lives in the gastrointestinal tract

73
Q

Flatworms

A

tapeworms and flukes
- often segmented

74
Q

Roundworms

A

unsegmented body

75
Q

General Worm Morphology

A
  • Multicellular animals that are equipped to some degree with organs and organ systems
76
Q

pathogenic helminths

A
  • the most developed organ is the
    reproductive tract
  • therefore, there is a reduction in the digestive, excretory, nervous,
    and muscular systems
77
Q

Life Cycles and Reproduction: pathogenic helminths

A

fertilized egg, larval, and adult stages
- adults reproduce in host, reproduce sexually
- Helminth sexes can be separate sexes (visually similar or distinct) or
hermaphroditic

78
Q

Helminth life cycle

A

infective form (egg or larva)
- larva develops is known as the intermediate (secondary) host
- Adulthood and mating occur in the definitive (final) host
- Transport host is an intermediate that experiences no parasitic development
- contaminated food, soil, and water or infected animals

79
Q

Egg Laying: Helminths

A

Vulnerable to heat, cold, drying, and
predators
- protective shell and extra
food
- Certain helminths can lay from 200,000 to 25 million eggs a day to assure successful completion
of their life cycle

79
Q

Taeniasis

A

tapeworms by eating raw or undercooked beef (Taenia saginata) or pork (Taenia solium and Taenia asiatica)

79
Q

beef

A

Taenia saginata

80
Q

pork

A

solium and asiatica

81
Q

Taeniasis causative agent

A

(Taenia saginata) and (Taenia
solium and Taenia asiatica)

82
Q

Taeniasis symptoms

A

symptoms are usually mild or nonexistent
- abdominal pain, loss of appetite, weight loss, and upset stomach
- visible sign of taeniasis is the active passing of proglottids (tapeworm segments) through the anus and in
the feces
- segments become lodged in the appendix, or the bile and pancreatic ducts
- Taenia solium infections can lead to cysticerosis, which is a disease that can cause seizures

83
Q

Ascariasis causative agent

A

Ascaris lumbricoides

84
Q

Ascariasis

A

most common human worm infection
- The larvae and adult worms live in the small intestine and can cause intestinal disease
- nasty for children

85
Q

Schistosomiasis (Bilharzia) causative agent

A

Schistosoma mansoni, S. haematobium, or S. japonicum

86
Q

Schistosomiasis (Bilharzia)

A

Second only to malaria as the most devastating parasitic disease (CDC)
- NTDs (neglected tropical disease)
- Contact with freshwater with certain snails
- enlarged liver, blood in the stool

87
Q

Elephantiasis (Bancroft’s filariasis) causative agent

A

Wuchereria bancrofti - nematodes

88
Q

Elephantiasis (Bancroft’s filariasis)

A

Vector: Mosquitoes
- Adult worm lives in lymph system
- Interrupts lymph flow
- Lymphedema swelling of mainly legs, but can also affect arms, breasts, and genitalia
- hardening and thickening of skin

89
Q

The most developed organ system in helminths is the?

A

reproductive

90
Q

Virus

A

a genetic element that contains either RNA or DNA surrounded by a protein capsid and that replicate only
inside host cells

91
Q

Viruses

A

Virus is Latin for “poison”
- Most abundant biological entities on Earth
- not alive
- most abundent
- infect every type of cell, including bacteria, algae, fungi, protozoa, plants, and animals

92
Q

Viruses

A
  • Needs host cell for energy, metabolic intermediates, protein synthesis
  • their own nucleic acid genome
93
Q

Discovery of Viruses

A

For many years, the cause of viral infections was unknown
- Louis Pasteur hypothesized that rabies was caused by a “living thing” smaller than bacteria
- 1884 → developed the first vaccine for rabies

94
Q

Filterable virus

A

fluids from host organisms passed through porcelain filters designed to trap bacteria, the filtrate remained infectious
- This proved that an infection could be caused by a fluid containing agents smaller than bacteria

95
Q

Filterable virus

A

Dmitri Ivanovski and Martinus Beijerinck showed that a disease in tobacco (plant virus) was caused by a virus
- Loeffler and Frosch discovered an animal virus that causes foot-and-mouth disease in cattle

96
Q

How did viruses originate?

A
  1. Progressive Hypothesis
    - Escaped genes
    exit one cell and enter another
    - evidence is retroviruses (HIV)
97
Q
  1. Regressive Hypothesis: Reductive evolution
A

lost genetic information
over time
- Adopted a parasitic approach to replication
- evidence is Nucleocytoplasmic large DNA viruses (NCLDVs)

98
Q
  1. Virus first
A

Viruses may have existed in a precellular world as self-replicating units
- evidence some viruses have only RNA
- Nucleus as a result of an endosymbiotic-like

99
Q

Are they organisms; that is, are they alive?

A

some traits of life
- rely on host
- do not consider them cells or alive
- described as either active or inactive

100
Q

What role did viruses play in the evolution of life?

A

Infect cells and influence their genetic makeup
- Shape the way cells, tissues, bacteria, plants, and animals have evolved
- 8% of the human genome consists of sequences that come from viruses
- 10 to 20% of bacterial DNA contains viral sequences
- Obligate intracellular parasites: invade a specific host cell and instruct its genetic and metabolic machinery to make and release new viruses

101
Q

What are their distinctive biological characteristics?

A
  • animal viruses were classified on the basis of their hosts and the
    diseases they caused (Old System)
  • Newer classification systems
    structure, chem composition, DNA and RNA makeup
102
Q

Properties of Viruses

A
  • obligate intracellular parasites
  • ubiquitous in nature and have had major impact on development
  • 10 times the number of bacteria and archaea combined
    -ultramicroscopic in size
  • Are not cells
  • protein shell (capsid) surrounding nucleic acid core
103
Q

pandora virus and mimivirus (largest)
(smallest known bacteria are rickettsia)

A
  • Nucleic acid can be either DNA or RNA, but not both at the same time
  • spikes: virus surfaces give them high specificity for attachment to host cell
  • Multiply by taking control of host cell’s genetic material
104
Q

resemble cells?

A

Viruses bear no resemblance to cells

105
Q

How much of the human genome consists of viral sequences?

A

8%

106
Q

Viral Components

A
  1. External coating
  2. Core containing nucleic acids (DNA or RNA)
  3. Matrix proteins and enzymes
    (occasionally)
107
Q

naked virus

A

nucleic acid and capsid (nucleocapsid)

108
Q

enveloped virus

A

envelope, phospholipid bilayer from host, nucleocapsid

109
Q

Nucleocapsid

A

nucleic acid + protein in
enveloped viruses

110
Q

Enveloped

A

viruses have an outer layer
consisting of a phospholipid bilayer (from host cell membrane) and viral proteins

111
Q

Naked

A

viruses have no other layers

112
Q

Capsid

A

the protein shell that surrounds the
genome of a virus

113
Q

Spikes

A

can be found on naked or
enveloped viruses:
* Project from the nucleocapsid or the envelope
* Allow viruses to dock with host cells

114
Q

Viral Capsid

A

Most prominent feature of viruses
- Constructed from identical protein
subunits called capsomeres
- Capsomeres spontaneously self-assemble into the finished capsid
- Two primary types:
1. Helical
2. Icosahedral

115
Q

Complex Capsid Structure

A

Complex capsids, only found
in the viruses that infect bacteria
- They are never enveloped

116
Q

Viral Envelope (on some)

A

Take a bit of the cell membrane when released
- More flexible than the capsid so enveloped viruses are pleomorphic

117
Q

How can particles so small, simple, and seemingly insignificant be
causing disease and death?

A

>

118
Q

Nucleic Acids

A

The Core of a Virus

119
Q

genome

A

Having a larger genome allows cells to carry out the complex
metabolic activity necessary for independent life
- Viruses typically possess only the genes needed to invade host
cells

120
Q

Multiplication Cycles in Animal Viruses

A

Viruses are minute parasites that seize control of the synthetic and genetic machinery of cells
General phases:
1. Adsorption - attach
2. Penetration
3. Uncoating - envelope has to be
4. Synthesis - make more
5. Assembly
6. Release
- The length of the replication cycle varies

121
Q

Adsorption

A

A virus can invade its host cell only through making an exact fit with a specific host molecule
- Host range: the limited range of cells that a virus can
infect

122
Q

Penetration and Uncoating

A

Direct fusion of the viral envelope with the host cell membrane (virus gets absorbed):
- Envelope merges directly with the cell membrane

Endocytosis (engulf) virus cell:
- penetrated by the whole virus or its nucleic acid
- entire virus is engulfed by the cell and enclosed in a vacuole or vesicle

123
Q

Synthesis: Replication and
Protein Production

A

DNA viruses:
* Enter the host cell’s nucleus and are replicated and assembled there
RNA viruses:
* Replicated and assembled in the cytoplasm

124
Q

Assembly and Release

A
  • Size of the virus
  • Health of the host cell
125
Q

Maturation and Release of Enveloped Viruses

A

Budding of enveloped viruses causes them to be shed gradually, without the sudden destruction of the cell.

126
Q

What is the connection between viruses and cancer?

A

Persistent Infections:
- carrier relationship

127
Q

Provirus

A

Viral DNA incorporated into the DNA of the host
- Measles virus. HIV.

128
Q

Chronic latent state

A

Periodically become activated
- (chickenpox and shingles)

129
Q

Viruses and Cancer

A

permanently alter its genetic material
* Many times, leading to cancer (oncogenic)

130
Q

Cancer-causing viruses

A

oncogenic

131
Q

cancers are caused by viruses

A

13%

132
Q

Transformation

A
  • Some viruses carry genes that directly cause cancer
  • Other viruses produce proteins
133
Q

Transformed cells

A
  1. Increased rate of growth
  2. Changes in their chromosomes
  3. Changes in cell’s surface molecules
  4. Capacity to divide indefinitely
134
Q

Oncoviruses: mammalian viruses capable of initiating tumors

A
  • Papillomaviruses
  • Herpesviruses
  • Hepatitis B virus
135
Q

Viruses That Infect Bacteria

A

Bacteriophage: “bacteria eating”

136
Q

Bacteriophage

A

infects the bacteria then can infect you

137
Q

T-Even Bacteriophage

A

Most widely studied phages
- Infect Escherichia coli

138
Q

Bacteriophages

A
  • all phages can enter into lytic
  • some enter lysogenic state
139
Q

temperate phages

A

can enter into lysogenic
- can enter prophage state

140
Q

induction

A

exit of lysogenic stage
- goes straight to step 3 of lytic cycle

141
Q

The Role of Lysogeny in Human Disease

A

phage genes in the bacterial chromosome can cause the production of toxins or enzymes that the bacterium would not otherwise have

142
Q

Lysogenic conversion

A

when a bacterium acquires a new trait from its temperate
phage
-diphtheria toxin
-cholera toxin
-botulinum toxin

Micro Exams (4 decks)

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