PARASITOLOGY Flashcards
(102 cards)
1
Q
Symbiosis
A
living together of phylogenetically different organisms
2
Q
Mutualism
A
beneficial to both organisms
3
Q
Commensalism
A
beneficial to one organism, neutral to the other
4
Q
Parasitism
A
beneficial to one organism, harmful to the other
5
Q
Definitive Host
A
harbors the adult or sexual stage of a parasite
6
Q
Examples of Definitive Host
A
- Cat - DH of T. gondii
- Mosquito (Female anopheles) - DH of Plasmodium spp.
7
Q
Intermediate Host
A
Harbors the larval or asexual stage of a parasite
7
Q
Examples of Intermediate Host
A
- Mosquitoes - IH of Filarial worms
- Snail - IH of ALL trematodes (schistosomes and hermaphrodites)
- Man - IH (accidental) host of Echinococcus spp. (Dog is DH)
8
Q
Paratenic Host
A
Harbors a parasite that does not develop but remains alive and if infective to the next host. Carries or bridges the parasite to the next host.
8
Q
Examples of Paratenic Host
A
- Large fish - PH of D. Latum
- Snake, bird - PH of G. spinigerum
9
Q
Obligate Parasite
A
Depends entirely upon its host for existence. MOST PARASITES ARE OBLIGATE PARASITES.
9
Q
Reservoir
A
Allows the parasite’s life cycle to continue and serves as a source of human infection
9
Q
Example of Reservoir
A
- Pig - RH of B. coli (also considered zoonotic)
10
Q
Facultative Parasite
A
Capable of parasitic and free-living existence
11
Q
Examples of Facultative Parasite
A
- S. stercoralis
- FLAs (Naegleria, Acanthamoeba spp.)
12
Q
Classification of parasite according to number of host required
A
Transitory, Permanent, Periodic
13
Q
Transitory parasite
A
Larval stage is passed in a host while the adult is free living in only 1 host
14
Q
Example of transitory parasite
A
S. stercoralis (INDIRECT LIFE CYCLE ONLY)
15
Q
Permanent parasite
A
Completes its life cycle in 1 host for all the life stages
16
Q
Example of permanent parasite
A
H. nana - the only cestode that is capable of this. Also called monoxenous or homoxenous (DIRECT LIFE CYCLE ONLY)
17
Q
Periodic parasite
A
Requires 2 or more hosts (heteroxenous) for the larval and adult stages
18
Q
Example of periodic parasite
A
Trematodes and cestodes (Except H. nana)
19
Q
Zoonotic parasite
A
Primarily infects animals and may be acquired by man and causes infection in man
20
Q
Examples of zoonotic parasite
A
- B. coli
- D. immitis
- Agents of larva migrans
21
Accidental parasite
Occurs in an unusual host
22
Examples of accidental parasites
1. Echinococcus
2. Agents of larva migrans (maturation is arrested at larval stage - meaning life cycle will not continue)
23
Erratic parasite
Occurs in an unusual organ or habitat
24
Example of erratic parasite
1. A. lumbricoides - can cause ectopic ascariasis (it is supposed to be in the small intestine)
25
Spurious or coprozoic parasites
Passes through the intestinal tract without causing any disturbance (DON'T CAUSE INFECTION)
26
Examples of spurious or coprozoic parasite
1. F. hepatica unembryonated eggs - not infectious, metacercaria is the infective stage in man
2. C. hepatica unembryonated eggs
27
Endoparasite
Lives inside the body of a host (MOST PARASITES ARE ENDOPARASITES)
28
What is it called when an endoparasite invades a host?
INFECTION
29
Ectoparasite
Lives on body surfaces
30
What is it called when an endoparasite invades a host?
INFESTATION
31
Examples of ectoparasites
1. Lice (Pediculus humanus capitis, P. h. humanus, Phthirus pubis)
2. Itch mite (Sarcoptes scabei)
32
Intermittent parasites
Visits the host only during feeding time
33
Examples of intermittent parasite
1. Bed bug
2. Mosquito
3. Flea
4. Tick
5. Biting fly
34
Arthropods are considered as?
Ectoparasite, Intermittent parasite, vectors
35
Biologic Vector
transmits a parasite only after the latter has completed part of its development; may also serve as a host
36
Mechanical or Phoretic
not essential in the parasite's life cycle and is responsible only for transporting the parasite via appendages or external surfaces
37
Examples of biological vectors
Mosquitoes
Biting flies
Kissing bugs
Ticks
38
Parasites transmitted by mosquitoes
Plasmodium spp., W. bancrofti, B. malayi
39
Parasites transmitted by biting flies
Leismania spp., T. brucei, Loa loa, Oncocerca
40
Parasites transmitted by kissing bugs (Reduviid or Triatomine)
T. cruzi
41
Parasites transmitted by ticks (Ixodes)
Babesia spp.
42
Examples of mechanical vectors
Cockroaches
House flies
43
Cockroaches and house flies are:
Mechanical vectors of A. lumbricoides and other enteric parasites (stool and soil)
44
Portal of Entry: Mouth/oral cavity
MOT: Ingestion
Example: ________
Most intestinal parasites
45
Portal of Entry: Mouth/oral cavity
MOT: Oral-anal intercourse
Example: ________
G. lamblia, E. histolytica, C. parvum, D. fragilis, E. vermicularis
46
Portal of Entry: Skin
MOT: Larval skin penetration
Example: ________
1. Hookworms
2. S. stercoralis
3. Schistosoma spp.
47
Portal of Entry: Skin
MOT: Skin inoculation (vector-borne)
Example: ________
1. Plasmodium spp.
2. Filariae
3. Babesia spp.
4. Leismania spp.
5. Trypanosoma spp.
48
Portal of Entry: Urogenital tract
MOT: Sexual intercourse (venereal)
Example: ________
T. vaginalis
49
Portal of Entry: Nasal passages
MOT: Intranasal
Example: ________
FLAs (Naegleria and Acanthamoeba spp.)
50
Portal of Entry: Transplacental
MOT: Vertical transmission (mother to fetus)
Example: ________
1. T. gondii
2. T. cruzi
3. Plasmodium spp.
51
Autoinfection can either be:
internal or external
52
Internal autoinfection
within the intestine
53
Examples of internal autoinfection
1. S. stercoralis - rhabditiform transforms into filariform in the intestine
2. C. philippinensis - atypical females
3. C. parvum
4. T. solium - reverse peristalsis of eggs (cysticercosis, can be fatal!)
54
External autoinfection
hand to mouth
55
Examples of external autoinfection
1. E. vermicularis
2. H. nana
56
Portals of exit
Anus
Mouth
Urogenital tract
Skin
57
Who coined the binomial system of nomenclature?
Carl Linnaeus
58
Genus
represents the taxon to which the species belongs; first letter is capitalized
59
Specific epithet
trivial name that distinguishes the species within the genus
60
Protozoa
unicellular eukaryotes
61
Phylum Sarcomastigophora
Amoebae and flagellates
62
Phylum Ciliophora
Ciliates (B. coli)
63
Phylum Apicomplexa
Sporozoans and coccidians
64
Similarity between Phylum Sarcomastigophora and Ciliophora
Asexual reproduction
Locomotory organelles
65
Characteristics of Phylum Apicomplexa
Sexual and asexual reproduction
Generally nonmotile
66
Other unicellular (not true protozoa) parasites include:
1. Blastocystic spp. - stramenophiles
2. Microsporidians - Encephalitozoon spp., enterocytozoon spp. (obligate intracellular fungi; smallest intestinal parasites (1.5 - 3 um)
3. Pneumocystis jirovecii - atypical fungus
67
Classification of helminths
Phylum Nemathelminthes
Phylum Platyhelminthes
68
Phylum Nemathelminthes
Nematodes (roundworms) - non hermaphroditic
69
Phylum Platyhelminthes
Tramatodes (flukes) - hermaphrodites (monoecious flukes) and non-hermaphrodites (schistosomes)
Cestodes (tapeworms) - hermaphroditic
70
Classification of arthropods
Class Arachnida
Class Insecta
Class Crustacea
71
Class Arachnida
Ticks
Mites
Chiggers (bacteriology - mite larvae)
72
Class Insecta
Mosquitoes
Flies
Midges
Bugs
Lice
Fleas & Beetles (IH of Hymenolepsis and D. caninum)
Cockroaches (Mechanical vector of A. lumbricoides)
73
Class Crustacea
Crabs and crayfish (2nd IH of P. westermani)
Copepods - cyclops, Diaptomus spp. (IH of D. medinensis, G. spinigerum; 1st IH of D. latum and Spinometra)
74
Clearance period of antacids, antidiarrheals, barium, bismuth, laxatives (leave crystalline residues)
7-10 days
75
Clearance period of antimicrobial agents
2-3 weeks
76
Clearance period of gallbladder dyes
2 weeks
77
Sufficient quantity of stool specimen
2-5 grams (thumb sized) - formed
5-6 tbsp - liquid
78
What should the label contain in a stool specimen?
Patient's name, age, sex, date and time of collection
79
Number of specimens to be examined for stool in parasitology:
3 spx collected on separate days within a 10 day period (to recover the parasites that shed diagnostic forms intermittently - e.g. G. lamblia, S. stercoralis)
80
Liquid stool specimens must be processed or preserved within
30 mins
81
Soft/semi-formed stool specimens must be processed or preserved within
1 hour
82
Formed stool specimens must be processed or preserved
up to 24 hours but must be refrigerated
83
For longer periods of preservation:
2-vial system - 1 part 10% formalin, 1 part PVA
84
Ratio of stool to preservative:
1 stool : 3 preservatives
85
10% formalin is an
All-purpose fixative
86
10% formalin can be used in:
WM (Wet Mount)
CT (Concentration Technique)
IA (Immunoassay)
87
Merthiolate-iodine-formalin can:
Fix and stain
88
Merthiolate-iodine-formalin can be used in:
WM (Wet Mount)
CT (Concentration Technique)
89
Sodium acetate-acetic acid formalin:
Can be used for permanent stains
90
Sodium acetate-acetic acid formalin can be used in:
WM (Wet Mount)
CT (Concentration Technique)
Permanent Staining (PS)
91
Schaudinn's fluid w/o PVA contain:
Mercuric Chloride (toxic to man)
92
Schaudinn's fluid w/o PVA can be used in:
Permanent Staining (PS)
93
PVA (SF w/ PVA) contain:
Mercuric Chloride (toxic to man)
94
PVA (SF w/ PVA) can be used in:
Permanent Staining (PS)
95
Modified PVA may be used in:
NAATs (PCR)
96
Modified PVA contain:
Zinc sulfate or copper sulfate
97
Modified PVA can be used in:
Permanent Staining (PS)
98
