1 - INTRODUCTION TO MEDICAL PARASITOLOGY Flashcards

1
Q
  • Branch of biology focused on the animal parasites of human and their significance to public health
  • From the Greek word, “parasitos” meaning food at the expense of others
A

Medical Parasitology

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2
Q

Living together for food and shelter

A

Symbiosis

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3
Q

Types of Symbiosis

A
  • Commensalism
  • Mutualism
  • Parasitism
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4
Q

1 benefits while the other is unharmed

A

Commensalism

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5
Q

both organisms benefit for each other

A

Mutualism

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6
Q

1 benefits while the other is harmed

A

Parasitism

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7
Q

Organism that provides physical protection and nourishment to the parasite

A

Host

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8
Q

Types of Host

A
  1. Definitive/Final Host
  2. Intermediate Host
  3. Paratenic Host
  4. Reservoir Host
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9
Q

harbors the adult or sexually mature stage of parasite

A

Definitive/Final Host

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10
Q

harbors the larval stage or asexual/immature forms of the parasite

A

Intermediate Host

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11
Q

early larval stage

A

1st Intermediate Host

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12
Q

infective/more mature larval stage; does not reach adult stage

A

2nd Intermediate Host

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13
Q

harbors underdeveloped stage / arrested stage of development

A

Paratenic Host

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14
Q

alternative host to a parasite that is harbored normally by humans

A

Reservoir Host

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15
Q

Caused by Filarial worms
Intermediate Host: insect
Final Host: human

A

Filariasis

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16
Q

Class of parasite
All infect snails as first intermediate host
Intermediate Host: snail

A

Trematodes (zombie snail)

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17
Q

Caused by Paragonimus westermani
2nd Intermediate Host: snail, crab, human
Paratenic Host: wild boar
Continues life cycle through ingestion

A

Paragonimiasis

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18
Q

Reservoir Host: pigs

A

Balantidium coli

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19
Q

Organism that depends on the host for survival

A

Parasite

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20
Q

a vector (arthropod) that serves as a vehicle to transfer a parasite to a host but is not essential in its life cycle

A

Mechanical Vector

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21
Q

arthropod that is essential to the life cycle

A

Biological Vector

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22
Q

Types of Parasites According to Relationship

A
  1. Obligate
  2. Facultative
  3. Temporary
  4. Intermittent
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23
Q

c

A

Obligate

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24
Q

free-living/commensal but have the tendency to become parasitic

A

Facultative

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25
Q

obligatory to 1 stage cycle but free-living in another

A

Temporary

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26
Q

visits the host only during feeding time

A

Intermittent

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27
Q

Types of Parasites According to Habitat

A
  1. Endoparasite
  2. Ectoparasite
  3. Erratic
  4. Coprophilic
  5. Hematozoic
  6. Cytozoic
  7. Coelozoic
  8. Enterozoic
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28
Q

within the host = infection (ex. Helminthic worms)

A

Endoparasite

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29
Q

outside the host = infestation (ex. ticks, fleas)

A

Ectoparasite

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30
Q

unusual place or habitat

A

Erratic

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31
Q

usually protozoans, able to multiple in fecal matter outside of the human body

A

Coprophilic

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32
Q

lives inside red blood cells

A

Hematozoic

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33
Q

lives in cells/tissues

A

Cytozoic

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34
Q

lives in body cavities

A

Coelozoic

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35
Q

parasite residing in intestines

A

Enterozoic

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36
Q

Adaptations to Parasitism

A
  1. Physiologic Adaptation
  2. Morphologic Adaptation
  3. Biochemical Changes
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37
Q

loss of enzymes

A

Physiologic Adaptation

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38
Q

c

A

Morphologic Adaptation

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39
Q

alteration of metabolic pathways and development of specialized mechanisms

A

Biochemical Changes

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40
Q

Effects of Parasites on Host (Mechanisms of Parasite Infection)

A
  1. Damage and obstruction to intestinal wall
  2. Destruction of tissues in intestinal wall
  3. Destruction of RBC, causing ischemia
  4. Perforation of bowel wall and invasion of nearby organs
  5. Competition against essential nutrients
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41
Q

Damage and obstruction to intestinal wall

A

Fasciolopsis buski (suckers)

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42
Q

Destruction of tissues in intestinal wall

A

Entamoeba histolytica (proteolytic enzymes)

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43
Q

Destruction of RBC, causing ischemia

A

Plasmodium falciparum

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44
Q

Perforation of bowel wall and invasion of nearby organs

A

Ascaris lumbricoides

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45
Q

Competition against essential nutrients

A
  • Human hookworms (N. americanus and A. duodanale)
  • Dibothriocephalus latus (deprives nutrients)
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46
Q

Human hookworms (N. americanus and A. duodanale)

A

Iron: Microcytic hypochromic anemia

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47
Q

Vit B12: Megaloblastic anemia

A

Dibothriocephalus latus (deprives nutrients)

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48
Q

Effects of Host on the Parasite

A
  1. Genetic Constitution
  2. Nutritional Status
  3. Immune Mechanisms
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49
Q

Genetic Constitution

A
  • Duffy null phenotype
  • Sickle cell trait
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50
Q

resistant to P. vivax

A

Duffy null phenotype

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51
Q

resistant to P. falciparum

A

Sickle cell trait

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52
Q

Nutritional Status

A
  • High-protein diet
  • Low-protein diet
  • Rich-carbohydrate diet
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53
Q

High-protein diet

A

unfavorable for development of intestinal protozoa

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54
Q

Low-protein diet

A

appearance of amoebiasis symptoms

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55
Q

Rich-carbohydrate diet

A

favors development of tapeworms

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56
Q

Immune Mechanisms

A

may be natural or acquired

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57
Q
  • Exist as motile trophozoite stage and the nonmotile infective cyst
  • Locomotor apparatus serves as one of the bases of classification
A

Protozoan

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58
Q
  • Sarcodina: amoebae: equipped with pseudopods or false feet
  • Mastigophora: flagellates: equipped with flagellum, a whip-like structure
A

Phylum Sarcomastigophora

59
Q
  • Ciliata: ciliates: equipped with cilia, hair-like structures
  • Some ciliates are multinucleate, while others contain but two nuclei, a large macronucleus, and a small micronucleus
A

Phylum Ciliophora

60
Q

only ciliate parasite of humans

A

Balantidium coli

61
Q
  • Parasites that are not equipped with definite locomotor apparatus
  • Demonstrates 2 cycles:
  • Schizogony – asexual cycle
  • Sporogony – sexual cycle
  • Contains apical complex that is composed of the ff: micronemes, subpellicular tubules, polar rings, conoids, rhoptries
A

Phylum Apicomplexa

62
Q

causative agent of malaria

A

Plasmodium spp.

63
Q

causative agent of Nantucket fever

A

Babesia microti

64
Q

causative agent of Toxoplasmosis

A

Toxoplasma gondii

65
Q
  • Flatworms
  • Characterized by a flat, bilaterally symmetrical body
  • Most are hermaphroditic; having both male and female reproductive organs in the same individual
  • Except schistosomes
  • Adults may be less than 1 mm long or they may reach a length of many meters
  • Most are parasites, living on or in the body of their hosts
A

Phylum Platyhelminthes

66
Q
  • Mostly existing as free-living forms inhabiting terrestrial, freshwater, and marine environments
  • Ciliated epithelium envelops the body of the adult worm
  • With or without suckers
  • Direct development without metamorphosis
  • Commensals or parasites of invertebrates especially of echinoderms and molluscs
A

Class Turbellaria

67
Q
  • “Flukes”
  • Leaf-shaped or elongated, slender organisms
  • Possess attachment organs in the form of cup-shaped muscular depressions called suckers
  • An incomplete digestive tract is present
  • Of the three orders of the
  • Trematoda, the order Digenea contains all the species that are parasitic in humans
  • Members of this order have complex life histories, with at least one intermediate molluscan host
  • Included in the digenetic trematodes of humans are forms that inhabit: small intestine, liver, lungs, pancreas, and blood vessels
A

Class Trematoda

68
Q
  • Elongated, ribbon-like, segmented body that bears a specialized anterior attachment organ called the scolex
  • A digestive tract is absent
  • Adult cestodes or tapeworms inhabit the small intestine
  • Cestode larvae require an intermediate host for development
  • Hymenolepis nana or the dwarf tapeworm may or may not require an intermediate host; autoinfection is also observed in its life cycle
  • Humans may be host to either adult or larval stages depending on the species of cestode
A

Class Cestoda

69
Q
  • Nematodes or roundworms
  • Elongated, cylindrical worms frequently attenuated at both ends
  • They possess a stiff cuticle which may be smooth or may be extended to form a variety of structures, particularly at the anterior and posterior ends
  • The sexes are separate
  • Males are frequently smaller than the female and possess copulatory structures like spicule or bursa
  • A complete digestive tract is present
  • A large number of species are parasitic
  • Intermediate hosts are necessary for the larval development of some forms
  • Parasites of humans include intestinal and tissue-inhabiting species
A

Phylum Nemathelminthes

70
Q
  • Formerly classified with the Sporozoa
  • Minute intracellular parasites of many kinds of vertebrates and invertebrates
  • Differ significantly in structure from the Apicomplexa
  • Rarely cause disease in immunocompetent persons, but may do so with greater frequency in immunosuppressed persons
  • Fungi-related microorganisms
  • Most human infections are caused by the ff genera: Enterocytozoon and Encephalitozoon
A

Phylum Microsporidia

71
Q

Life Cycle

A
  1. Mode of Transmission
  2. Infective Stage
  3. Diagnostic Stage
72
Q

means whereby a parasite gains entry into an unsuspecting host

A

Mode of Transmission

73
Q

morphologic forms which invades humans

A

Infective Stage

74
Q

forms that can be detected in laboratory retrieval methods (nag-iiba based on lab test)

A

Diagnostic Stage

75
Q

Multicellular

A

aMetazoan

76
Q

Unicellular

A

Protozoan

77
Q

Life Stages of a Protozoan Parasite

A
  1. Cyst
  2. Trophozoite
78
Q

nonmotile, resting/nonfeeding form

A

Cyst

79
Q

motile, active/feeding form

A

Trophozoite

80
Q

transformation from trophozoite to cyst stage

A

Encystation

81
Q

transformation from cyst to trophozoite stage

A

Excystation

82
Q

Life Stages of a Metazoan Parasite

A
  1. Ova/Egg
  2. Larva
  3. Adult
83
Q

Modes of Reproduction

A
  1. Sexual
  2. Asexual
84
Q

release unembryonated/immature eggs; is not infective right away

A

Oviparous

85
Q

release embryonated eggs; already infective (autoinfection)

A

Ovoviviparous

86
Q

release larva directly/immediately

A

Larviparous

87
Q

like mitosis

A

Binary Fission

88
Q

Parasite Transmission Based on Transmission

A
  1. Soil-transmitted
  2. Vector-transmitted
  3. Food-borne
  4. Water-borne
  5. Direct Contact
89
Q

Through ingestion

A

Ascaris lumbricoides
Trichuris trichiura

90
Q

Through skin penetration

A

Hookworm
Strongyloides stercoralis

91
Q

Unholy Three

A
  • Most common parasites
  • Can be present simultaneously
  • Ascaris lumbricoides
  • Trichuris trichiura
  • Strongyloides stercoralis
92
Q

Any agent which carries and transmits an infectious organism into another living organism

A

Vector-transmitted

93
Q

such as mosquitoes and ticks may carry pathogens that can multiply within their bodies and be delivered to new hosts, usually by biting

A

Biological Vector

94
Q

such as flies can pick up infectious agents on the outside of their bodies and transmit them through physical contact

A

Mechanical Vector

95
Q

Examples of Vectors

A
  • mosquito
  • tsetse fly
  • reduviid bug
  • sand-fly
  • ticks
  • snails
  • black fly
  • fruitfly
96
Q

causative agent of malaria

A

Plasmodium spp.

97
Q

causative agent of filariasis

A

Wuchereria bancrofti

98
Q

causative agent of sleeping sickness

A

Trypanosoma brucei

99
Q

causative agent of chagas disease

A

Trypanosoma cruzi

100
Q

causative agent of leishmaniasis

A

Leishmania spp

101
Q

causative agent of babesiosis

A

Babesia microti

102
Q

Snails

A

Schistosoma spp

103
Q

Black Fly

A

Onchocerca volvulus

104
Q

Fruit Fly

A

Loa loa

105
Q

Copepods

A

Dracunculus medinensis

106
Q

From raw pork meat

A

Taenia solium
Trichinella spiralis
Toxoplasma gondii

107
Q

From raw beef

A

Taenia saginata (beef tapeworm)

108
Q

From raw fish

A

Heterophyes heterophyes
Clonorchis sinensis
Opistorchis spp

109
Q

From crabs/crustaceans

A

Paragonimus westermani

110
Q

From vegetables

A

Fasciola spp
Fasciolopsis buski

111
Q

Water-borne protozoans

A

Intestinal Amoeba
Intestinal Flagellates
Intestinal Coccidian

112
Q

Direct Contact

A

Trichomonas vaginalis
Enterobius vermiculari

113
Q

Portals of Entry

A
  1. mouth
  2. skin
  3. intranasal
  4. transmamary
  5. sexual
114
Q

Embryonated egg

A

Ascaris, Trichuris

115
Q

Cyst

A

Entamoeba histolytica

116
Q

Metacercaria

A

Fasciola spp

117
Q

Trophozoite

A

Entamoeba gingivalis

118
Q

Filariform Larvae

A

Hookworm & Strongyloides stercoralis

119
Q

Cercaria

A

Schistosoma japonicum

120
Q

Sporozoites

A

Plasmodium spp

121
Q

Trypomastigotes

A

Trypanosoma spp

122
Q

Intranasal

A

Naegleria fowleri trophozoite

123
Q

Transmammary

A

Ancylostoma duodenale (hookworm)

124
Q

Sexual

A

Trichomonas vaginalis

125
Q

Infected individual becomes his own direct source of infection

A

Autoinfection

126
Q
  • Already infected individual is further infected with the same species leading to massive infection with the parasite
  • Also known as hyperinfection
A

Superinfection

127
Q

Portals of Exit

A
  1. Stool
  2. Blood
  3. Sputum
  4. Urine
128
Q

Stool

A

Ascaris lumbricoides
Trichuris
Hookworm
Taenia
Entamoeba

129
Q

Blood

A

Plasmodium spp
Wuchereria
Trypanosoma

130
Q

Sputum

A

Paragonimus
Ascaris

130
Q

Urine

A

Schistosoma haematobium
Trichomonas vaginalis

131
Q

Study of occurrence and distribution of disease in human population and communities

A

Epidemiology

132
Q

No. of cases of a disease that are present in the population at a given time

A

Prevalence

133
Q

No. of new cases that developed

A

Incidence

134
Q

The act of occurring again

A

Recurrence

135
Q

Clinical consequences of infections or diseases

A

Morbidity

136
Q

No. of deaths within a particular society and period of time

A

Mortality

137
Q

No. of worms per infected persons

A

Intensity of Infection

138
Q

When a disease in a population maintains a relatively steady, moderate level

A

Endemic

139
Q

When an outbreak of considerable intensity/sharp rise occur

A

Epidemic

140
Q

If the prevalence of a disease is high

A

Hyperendemic

141
Q

If it appears only occasionally in one or few members of the community

A

Sporadic

142
Q

The disease covers extensive area of the world

A

Pandemic