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GENERAL PARASITOLOGY > LEC 6 - Food-borne Nematodes Pt. 1 > Flashcards

LEC 6 - Food-borne Nematodes Pt. 1 Flashcards

1
Q

Parasite/s found in Crabs, shrimp

A

Gnathostoma

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2
Q

Parasite/s found in Freshwater Fish

A

Capillaria

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3
Q

Parasite/s found in Marine fish

A

Anisakis, Gnathostoma, Pseudoterranova

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4
Q

Parasite/s found in Fruits, vegetables

A

Angiostrongylus, Ascaris

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5
Q

Parasite/s found in Squid

A

Anisakis

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6
Q

Parasite/s found in Water

A

Ascaris, Gnathostoma

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7
Q

Parasite/s found in Other Meat

A

Gnathostoma (frogs, snakes)
Trichinella (bear, cougar , horse, walrus, wild boar)

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8
Q

humans can get the disease from animal exposure (usually through ingestion – inadequate cooking/improper preparation)

A

ZOONOTIC PARASITES

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9
Q

Meat-borne parasites occurring in livestock (domesticated animals)

A

Farm to Fork Food Chain

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10
Q

Trichinella (infective encysted larvae is found in pork muscle) is example of what food chain

A

Farm to Fork Food Chain

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11
Q

Meat-borne parasites occurring in wildlife (bears, cougars, etc.)

A

Forest to Fork Food Chain

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12
Q

Example of Forest to Fork Food Chain

A

Trichinella

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13
Q

Fish-borne parasites –consumption of either
freshwater/seawater (aquatic/marine) fishes

A

Freshwater/Ocean/Pond to Fork Food Chain

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14
Q

Example of Freshwater/Ocean/Pond to
Fork Food Chain

A

Anisakis – usually from seawater and brackish water
Capillaria – ingestion of freshwater fish

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15
Q
  • A metastrongyloid parasite (that occurs in the lungs of mammals)
A

Angiostrongylus

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16
Q

Rat Lungworm

A

Angiostrongylus/Parastrongylus cantonensis

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17
Q

Disease caused by A. cantonensis

A

Angiostrongyliasis, Eosinophilic meningitis/ Neural angiostrongyliasis

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18
Q

target is CNS occasionally, ocular disease

A

Angiostrongyliasis, Eosinophilic meningitis/ Neural angiostrongyliasis

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19
Q

Disease caused by A. costaricensis

A

Angiostrongyliasis, Eosinophilic gastroenteritis (abdominal/intestinal angiostrongyliasis)

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20
Q

Definitive host A. cantonencis

A
  • Black/ House/ Roof/ Ship rat (Rattus rattus)
  • Brown/Norway rat (Rattus norvegicus)
  • Hispid cotton rat (Sigmodon hispidus)
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21
Q

Definitive host A. costaricensis

A
  • Hispid cotton rat (Sigmodon hispidus) – Main
  • Black rat (Rattus rattus)
  • Pygmy rice rat (Oligoryzomys fulvescens)
  • Short-tailed canemouse/ short-tailed zygodonts (Zygodontomys brevicauda)
  • Spiny pocket mice (Heteromys adsperus)
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22
Q

Intermediate host of A. cantonensis

A

Gastropod (slugs and snails):
- Achatina spp.
- Biomphalaria spp.
- Bulinus spp.
- Lymnaea spp.
- Pomaecea spp.
In the Philippines:
* Achatina fulica (Giant African snail)
* Helicostyla macrostoma
* Hemiplecta sagittifera
* Vaginilus plebeius
*Veronicella altae

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23
Q

Intermediate host of A. costaricensis

A

Gastropod (slug):
- Limacidae family
- Veronicellidae family

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24
Q

Aberrant/ Incidental host of A. cantonensis

A

Humans, birds, wild and domestic mammals

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25
Q

Aberrant/ Incidental host of A. costaricensis

A

Humans, non-human primates, and other mammals (opossum, raccoons)

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26
Q

Distribution of A. cantonensis

A

Predominant in SEA, tropical Pacific Islands; seen also in Africa, Australia, Caribbean, Hawaii and Southern US

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27
Q

Distribution of A. costaricensis

A

Caribbean, Latin America

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28
Q

Specimen for A. cantonensis

A

Brain tissue, CSF (Neural)

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29
Q

Specimen for A. costaricensis

A

Intestinal tissue section

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30
Q

Laboratory Diagnosis of A. cantonensis

A

Abnormal CSF:
* Elevated pressure
* (+) protein
* (+) leukocyte
* Eosinophilia
* Rarely: (+) parasite larvae

Presence of proteins and leukocyte are signs of non-specific inflammatory reactions

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31
Q

Laboratory Diagnosis of A. costaricensis

A

Finding of eggs, larvae, or adult in tissue sections taken through biopsy/surgery

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32
Q

Molecular diagnosis of A. cantonensis

A

CSF real-time PCR –identification of parasite genes in a sample

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33
Q

Molecular diagnosis of A. costaricensis

A

Tissue conventional PCR, then DNA sequence analysis (no specific molecular test is available)

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34
Q

Treatment for A. cantonensis

A

None (Supportive treatment only)

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35
Q

Treatment for A. costaricensis

A

None, but may require surgery

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36
Q

Prevention and Control for A. cantonensis

A
  • Health education
  • Avoid consumption of raw/undercooked slugs, snails, freshwater shrimps, land crabs, frogs, monitor lizards (transport hosts), or contaminated vegetable and vegetable juices
  • Remove slugs, snails, and rats near gardens and houses
  • Thoroughly wash vegetables if eaten raw
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37
Q

Prevention and Control for A. costaricensis

A
  • Health education
  • Avoid consumption of raw/undercooked slugs or contaminated vegetable/vegetable juices
  • Remove slugs and rats near gardens and houses
  • Throughly wash hands and utensils after preparing slugs
  • Thoroughly wash vegetables if eaten raw
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38
Q

Cantonensis: first found in

A

Canton, China

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39
Q

Costaricensis: first found in

A

Costa Rica

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40
Q

group of parasites that reside in lungs of certain mammals

A

Metastrongyloid

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41
Q

: reside in lungs of rodents

A

Angiostrongylus

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42
Q

Lifecycle of Angiostrongylus cantonensis

A

1) Eggs hatch in lungs, first stage larvae are passed in rodent feces
2) First-stage larva shed from definitive host are ingested by gastropod (intermediate host)
3) Larvae reach infective stage (L3) after two molts in the intermediare host
4) Third-stage larva are ingested by the definitive host
5) Accidental ingestion of gastropod or larvae (e.g. contaminated produce)
6) Larvae migrate to the brain (occasionally eyes or lungs) in aberrant human host, and DO NOT REACH REPRODUCTIVE MATURITY

43
Q

Lifecycle of Angiostrongylus costaricensis

A

differ in target area from A. cantonensis (intestine)
* Larvae migrate to intestinal wall and maturation may occur
* Adult parasites reside in the ileocecal mesenteric arteries

44
Q

Morphology of Adult A. cantonensis - Female

A
  • Bigger than male (3 cm long)
  • Barber’s pole appearance of the parasite
  • Vaginal opening (vulva) at the subterminal posterior portion of the body
  • Made up of:
  • dark red intestine tract filled with blood intertwined; with
  • a pair of the white genital tract (uterus)
45
Q

Morphology of Adult A. cantonensis - Male

A
  • Posterior end showing a small bursa—used for copulation and two copulatory spicules
46
Q
  • Extraintestinal nematode
  • An aphasmid worm (Adenophorea) with Capillaria, Trichuris, and Hymenolepis nana
    (aphasmid cestode
A

Trichinella spp.

47
Q

sensory organ found in the posterior part of nematodes

48
Q

Aphasmid Nematodes

A

Trichuris, Capillaria, Trichinella

49
Q

Source and Distribution of T. spiralis

A

Carnivorous and omnivorous animals (Pigs=primary reservoir host) - Worldwide

50
Q

Source and Distribution of T. pseudospiralis

A

Birds and mammals - Worldwide

51
Q

Source and Distribution of T. britovi

A

Carnivorous animals - Worldwide

52
Q

Source of T. nativa

A

Arctic bears

53
Q

Source and Distribution of T. nelsoni

A

African predators and scavengers

54
Q

Source and Distribution of T. papuae

A

Wild and domesticated pigs - Papua New Guinea and Thailand

55
Q

Common name of T. spiralis

A

Garbage/pork/trichina worm

56
Q

Disease caused by T. spiralis

A

Trichinellosis/Trichinosis, Neurotrichinellosis –affects the CNS due to larva migration

57
Q

Definitive/intermediate and reservoir host of T. spiralis

58
Q

Aberrant host of T. spiralis

59
Q

MOT of T. spiralis

A

Ingestion of muscle tissue infected with encysted larvae (consumption of undercooked pork)

60
Q

Habitat of T. spiralis

A

Small intestine – jejunum (Adults) Striated muscle (Larvae)
Larvae → distribute throughout the muscles due to intestinal absorption and circulation

61
Q

Manner of Reproduction of T. spiralis

A

Viviparous
* Male dies after fertilizing the female
* Female dies after 16 weeks (after discharging the larvae)

62
Q

Target site of larva: (T. spiralis)

A

striated smooth muscle

63
Q

Clinical Manifestations of T. spiralis

A

Diarrhea, facial edema, fever, headache,
myalgia

Neurotrichinellosis

64
Q
  • Sequelae (consequence) of severe
    trichinella infection
  • Encelopathy
  • Neuromuscular disturbance
  • Ocular involvement
A

Neurotrichinellosis

65
Q

(T. spiralis) 10 larvae =

A

Asymptomatic

66
Q

(T. spiralis) 50-500 larvae =

A

Symptomatic (moderate infection)

67
Q

(T. spiralis) 1000-3000 larvae =

A

Severe infetion

68
Q

Phases of the Neurotrichinellosis: – incubation and intestinal invasion

A

Enteric Phase

69
Q

Phases of the Neurotrichinellosis – larval migration and muscle invasion

A

Invasion Phase

70
Q

Phases of the Neurotrichinellosis - encystment and encapsulation

A

Covalescent Phase

71
Q

Diagnosis (T. spiralis)

A

Muscle biopsy
Muscle digestion technique using HCl and Pepsin
Serology
Molecular techniques
Nonspecific tests:

72
Q

demonstration of larvae in histological examination of 0.2-0.5 gram of muscle tissue) – most definitive diagnosis of T. spiralis

A

Muscle biopsy

73
Q

Commonly used muscle for Muscle Biopsy

A

DELTOID MUSCLE

74
Q

determine the number of larvae per gram muscle

A

Muscle digestion technique using HCl and Pepsin

75
Q

Disadvantage of Muscle digestion technique using HCl and Pepsin

A

Younger larvae may be digested, hence used to digest 10-12 days old muscle larvae (can be done 2-3 weeks post-infection)

76
Q

(T. spiralis) Diagnosis - Serology

A
  • ELISA
  • Western Blot technique – confirmatory
    test
  • Latex agglutination – rapid test, non-conclusive due to cross-reactions (with Strongyloides stercoralis); screening tests for initial diagnosis
76
Q

(T. spiralis) Diagnosis - Molecular Techniques

A

Polymerase Chain Reaction (PCR)

77
Q

(T. spiralis) Diagnosis - Non specific tests

A
  • Eosinophilia
  • Increased muscle enzymes (XK, LDH, myokinase) due to muscular damage
  • Increased total serum IgE
78
Q

(T. spiralis) GROUP A Symptoms

A

Fever, eyelid and/or facial edema, myalgia

79
Q

(T. spiralis) GROUP B Symptoms

A

Diarrhea, neurological signs, cardiac signs,
conjunctivitis, subungual hemorrhages,
cutaneous rash

80
Q

(T. spiralis) GROUP C Symptoms

A

Eosinophilia (>1,000/mL blood) and/or
increased total IgE levels, increased levels of
muscular enzymes

81
Q

(T. spiralis) GROUP D Symptoms

A

Positive serology (with a highly specific test)

82
Q

(T. spiralis) 3 Group A and one Group C symptoms - INTERPRETATION

83
Q

(T. spiralis) only 1 symptom from Group A, B, or C
- INTERPRETATION

A

Very unlikely

84
Q

(T. spiralis) the presence of 1 symptom from Group A or two from Group B, and one from
Group - INTERPRETATION

85
Q

(T. spiralis) presence of 3 Group A and 2 Group C symptoms - INTERPRETATION

A

Highly probable

86
Q

(T. spiralis) 3 Group A, 2 Group C, 1 Group D; or any of symptoms from Group A or B, and one from Group C and one from Group D - INTERPRETATION

87
Q

Trichinella spiralis - Human Lifecycle (Accidental/Aberrant)

A

1) Human ingestion of infected pig (most likely means of transmission)
2) Processed meat, ham, sausage (homemade)
3) Improperly cooked meat ingested by human
4) DEAD END

88
Q

Trichinella spiralis - Pig Lifecycle

A

1) Pig eat larva → enzymes digest meat, larva remain → small intestine
2) Larva excysts in small intestine and develops to adult (copulation)
3) L1 larva deposited and absorbed in intestinal tissue
4) Enter blood circulation
5) Enter striated muscle
6) Encysts in muscle cells

89
Q

Three Lifecycles of T. spiralis

A
  • Urban/Domestic
  • Marine
  • Sylvatic
90
Q

Lifecycles of T. spiralis - Poorly cooked pork is ingested/eaten by man

A

Urban/Domestic

91
Q

Lifecycles of T. spiralis - Predators and scavengers become hosts of the parasite

92
Q

Lifecycles of T. spiralis - Polar bears, seals, walruses, and whales become hosts of the parasite

93
Q

Morphology of T. Spiralis - Adult

A
  • Females are larger than males
  • Smallest nematodes in human
  • Male
    • No spicule
    • Pair of conspicuous papillae (claspers) – uses to hold female during reproduction
  • Females are VIVIPAROUS (not sure)
94
Q

Morphology of T. Spiralis - Larva

A
  • 80x7-8 mcm
  • Encysted larva: 1 mm length x 36 mcm
  • NOTE: encystation only occur in striated muscles (not in other tissues as they degenerate and are absorbed → calcification
95
Q

Lifespan of T. Spiralis (encysted)

A

5-10 years, or up to 40 years (chronic infection especially if asymptomatic)

96
Q

Calcification of infected muscle cell + larva:

A

6-12 months post-infection
- Creation of a nurse cell is 6-12 months
- Pepsin-HCl digestion releases larva from nurse cell

97
Q
  • Muscle biopsy (get sample)
  • Add HCl-Pepsin to digest muscle to release encysted larvae
A

Pepsin-HCl digestion as Diagnostic Tool (Muscle Digestion Technique

98
Q

T. Spiralis Treatment - Mebendazole

A

5 mg/kg daily for 10-15 days

99
Q

T. Spiralis Treatment - Albendazole

A

15 mg/kg of body weight daily in 2 divided doses for 10-15 days

Children >=2 years old: 10mg/kg body weight daily in 2 divided doses for 10-15 day

100
Q

T. Spiralis Treatment - Thiobendazole

A

Not used for adverse drug reactions

101
Q

T. Spiralis Treatment -Supportive treatments
(analgesics, antipyretics, corticosteroids)

A

Control symptoms (corticosteroids= control hypersensitivity from larvae. Treat myosistis and vasculitis)

102
Q

T. Spiralis Prevention and Control

A
  • Health education
  • Adequate cooking of meat (minimum of +77 C or +170 F)
  • Freezing or storing at -15 C for 20 days or -30 C C for 6 days
  • Regular animal monitoring
  • Keep pigs in rat-free pens
  • Proper disposal of suspected carcasses
103
Q

NOTE: Salting, smoking, or drying of meat DOES NOT KILL THE LARVAE of T. spiralis

A

OMSIM lods

GENERAL PARASITOLOGY (7 decks)

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