LEC 6 - Food-borne Nematodes Pt. 1 Flashcards
(104 cards)
1
Q
Parasite/s found in Crabs, shrimp
A
Gnathostoma
2
Q
Parasite/s found in Freshwater Fish
A
Capillaria
3
Q
Parasite/s found in Marine fish
A
Anisakis, Gnathostoma, Pseudoterranova
4
Q
Parasite/s found in Fruits, vegetables
A
Angiostrongylus, Ascaris
5
Q
Parasite/s found in Squid
A
Anisakis
6
Q
Parasite/s found in Water
A
Ascaris, Gnathostoma
7
Q
Parasite/s found in Other Meat
A
Gnathostoma (frogs, snakes)
Trichinella (bear, cougar , horse, walrus, wild boar)
8
Q
humans can get the disease from animal exposure (usually through ingestion – inadequate cooking/improper preparation)
A
ZOONOTIC PARASITES
9
Q
Meat-borne parasites occurring in livestock (domesticated animals)
A
Farm to Fork Food Chain
10
Q
Trichinella (infective encysted larvae is found in pork muscle) is example of what food chain
A
Farm to Fork Food Chain
11
Q
Meat-borne parasites occurring in wildlife (bears, cougars, etc.)
A
Forest to Fork Food Chain
12
Q
Example of Forest to Fork Food Chain
A
Trichinella
13
Q
Fish-borne parasites –consumption of either
freshwater/seawater (aquatic/marine) fishes
A
Freshwater/Ocean/Pond to Fork Food Chain
14
Q
Example of Freshwater/Ocean/Pond to
Fork Food Chain
A
Anisakis – usually from seawater and brackish water
Capillaria – ingestion of freshwater fish
15
Q
- A metastrongyloid parasite (that occurs in the lungs of mammals)
A
Angiostrongylus
16
Q
Rat Lungworm
A
Angiostrongylus/Parastrongylus cantonensis
17
Q
Disease caused by A. cantonensis
A
Angiostrongyliasis, Eosinophilic meningitis/ Neural angiostrongyliasis
18
Q
target is CNS occasionally, ocular disease
A
Angiostrongyliasis, Eosinophilic meningitis/ Neural angiostrongyliasis
19
Q
Disease caused by A. costaricensis
A
Angiostrongyliasis, Eosinophilic gastroenteritis (abdominal/intestinal angiostrongyliasis)
20
Q
Definitive host A. cantonencis
A
- Black/ House/ Roof/ Ship rat (Rattus rattus)
- Brown/Norway rat (Rattus norvegicus)
- Hispid cotton rat (Sigmodon hispidus)
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)
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
23
Q
Intermediate host of A. costaricensis
A
Gastropod (slug):
- Limacidae family
- Veronicellidae family
24
Q
Aberrant/ Incidental host of A. cantonensis
A
Humans, birds, wild and domestic mammals
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Aberrant/ Incidental host of A. costaricensis
Humans, non-human primates, and other mammals (opossum, raccoons)
26
Distribution of A. cantonensis
Predominant in SEA, tropical Pacific Islands; seen also in Africa, Australia, Caribbean, Hawaii and Southern US
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Distribution of A. costaricensis
Caribbean, Latin America
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Specimen for A. cantonensis
Brain tissue, CSF (Neural)
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Specimen for A. costaricensis
Intestinal tissue section
30
Laboratory Diagnosis of A. cantonensis
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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Laboratory Diagnosis of A. costaricensis
Finding of eggs, larvae, or adult in tissue sections taken through biopsy/surgery
32
Molecular diagnosis of A. cantonensis
CSF real-time PCR –identification of parasite genes in a sample
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Molecular diagnosis of A. costaricensis
Tissue conventional PCR, then DNA sequence analysis (no specific molecular test is available)
34
Treatment for A. cantonensis
None (Supportive treatment only)
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Treatment for A. costaricensis
None, but may require surgery
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Prevention and Control for A. cantonensis
* 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
37
Prevention and Control for A. costaricensis
* 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
38
Cantonensis: first found in
Canton, China
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Costaricensis: first found in
Costa Rica
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group of parasites that reside in lungs of certain mammals
Metastrongyloid
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: reside in lungs of rodents
Angiostrongylus
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Lifecycle of Angiostrongylus cantonensis
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
Lifecycle of Angiostrongylus costaricensis
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
Morphology of Adult A. cantonensis - Female
- 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)
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Morphology of Adult A. cantonensis - Male
- Posterior end showing a small bursa—used for copulation and two copulatory spicules
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- Extraintestinal nematode
- An aphasmid worm (Adenophorea) with Capillaria, Trichuris, and Hymenolepis nana
(aphasmid cestode
Trichinella spp.
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sensory organ found in the posterior part of nematodes
Phasmid
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Aphasmid Nematodes
Trichuris, Capillaria, Trichinella
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Source and Distribution of T. spiralis
Carnivorous and omnivorous animals (Pigs=primary reservoir host) - Worldwide
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Source and Distribution of T. pseudospiralis
Birds and mammals - Worldwide
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Source and Distribution of T. britovi
Carnivorous animals - Worldwide
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Source of T. nativa
Arctic bears
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Source and Distribution of T. nelsoni
African predators and scavengers
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Source and Distribution of T. papuae
Wild and domesticated pigs - Papua New Guinea and Thailand
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Common name of T. spiralis
Garbage/pork/trichina worm
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Disease caused by T. spiralis
Trichinellosis/Trichinosis, Neurotrichinellosis –affects the CNS due to larva migration
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Definitive/intermediate and reservoir host of T. spiralis
Pigs/rats
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Aberrant host of T. spiralis
Humans
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MOT of T. spiralis
Ingestion of muscle tissue infected with encysted larvae (consumption of undercooked pork)
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Habitat of T. spiralis
Small intestine – jejunum (Adults) Striated muscle (Larvae)
Larvae → distribute throughout the muscles due to intestinal absorption and circulation
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Manner of Reproduction of T. spiralis
Viviparous
* Male dies after fertilizing the female
* Female dies after 16 weeks (after discharging the larvae)
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Target site of larva: (T. spiralis)
striated smooth muscle
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Clinical Manifestations of T. spiralis
Diarrhea, facial edema, fever, headache,
myalgia
Neurotrichinellosis
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- Sequelae (consequence) of severe
trichinella infection
* Encelopathy
* Neuromuscular disturbance
* Ocular involvement
Neurotrichinellosis
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(T. spiralis) 10 larvae =
Asymptomatic
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(T. spiralis) 50-500 larvae =
Symptomatic (moderate infection)
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(T. spiralis) 1000-3000 larvae =
Severe infetion
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Phases of the Neurotrichinellosis: – incubation and intestinal invasion
Enteric Phase
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Phases of the Neurotrichinellosis – larval migration and muscle invasion
Invasion Phase
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Phases of the Neurotrichinellosis - encystment and encapsulation
Covalescent Phase
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Diagnosis (T. spiralis)
Muscle biopsy
Muscle digestion technique using HCl and Pepsin
Serology
Molecular techniques
Nonspecific tests:
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demonstration of larvae in histological examination of 0.2-0.5 gram of muscle tissue) – most definitive diagnosis of T. spiralis
Muscle biopsy
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Commonly used muscle for Muscle Biopsy
DELTOID MUSCLE
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determine the number of larvae per gram muscle
Muscle digestion technique using HCl and Pepsin
75
Disadvantage of Muscle digestion technique using HCl and Pepsin
Younger larvae may be digested, hence used to digest 10-12 days old muscle larvae (can be done 2-3 weeks post-infection)
76
(T. spiralis) Diagnosis - Serology
* ELISA
* Western Blot technique – confirmatory
test
* Latex agglutination – rapid test, non-conclusive due to cross-reactions (with Strongyloides stercoralis); screening tests for initial diagnosis
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(T. spiralis) Diagnosis - Molecular Techniques
Polymerase Chain Reaction (PCR)
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(T. spiralis) Diagnosis - Non specific tests
* Eosinophilia
* Increased muscle enzymes (XK, LDH, myokinase) due to muscular damage
* Increased total serum IgE
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(T. spiralis) GROUP A Symptoms
Fever, eyelid and/or facial edema, myalgia
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(T. spiralis) GROUP B Symptoms
Diarrhea, neurological signs, cardiac signs,
conjunctivitis, subungual hemorrhages,
cutaneous rash
80
(T. spiralis) GROUP C Symptoms
Eosinophilia (>1,000/mL blood) and/or
increased total IgE levels, increased levels of
muscular enzymes
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(T. spiralis) GROUP D Symptoms
Positive serology (with a highly specific test)
82
(T. spiralis) 3 Group A and one Group C symptoms - INTERPRETATION
Probable
83
(T. spiralis) only 1 symptom from Group A, B, or C
- INTERPRETATION
Very unlikely
84
(T. spiralis) the presence of 1 symptom from Group A or two from Group B, and one from
Group - INTERPRETATION
Suspect
85
(T. spiralis) presence of 3 Group A and 2 Group C symptoms - INTERPRETATION
Highly probable
86
(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
Confirmed
87
Trichinella spiralis - Human Lifecycle (Accidental/Aberrant)
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
Trichinella spiralis - Pig Lifecycle
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
Three Lifecycles of T. spiralis
- Urban/Domestic
- Marine
- Sylvatic
90
Lifecycles of T. spiralis - Poorly cooked pork is ingested/eaten by man
Urban/Domestic
91
Lifecycles of T. spiralis - Predators and scavengers become hosts of the parasite
Sylvatic
92
Lifecycles of T. spiralis - Polar bears, seals, walruses, and whales become hosts of the parasite
Marine
93
Morphology of T. Spiralis - Adult
- 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
Morphology of T. Spiralis - Larva
- 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
Lifespan of T. Spiralis (encysted)
5-10 years, or up to 40 years (chronic infection especially if asymptomatic)
96
Calcification of infected muscle cell + larva:
6-12 months post-infection
- Creation of a nurse cell is 6-12 months
- Pepsin-HCl digestion releases larva from nurse cell
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- Muscle biopsy (get sample)
- Add HCl-Pepsin to digest muscle to release encysted larvae
Pepsin-HCl digestion as Diagnostic Tool (Muscle Digestion Technique
98
T. Spiralis Treatment - Mebendazole
5 mg/kg daily for 10-15 days
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T. Spiralis Treatment - Albendazole
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
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T. Spiralis Treatment - Thiobendazole
Not used for adverse drug reactions
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T. Spiralis Treatment -Supportive treatments
(analgesics, antipyretics, corticosteroids)
Control symptoms (corticosteroids= control hypersensitivity from larvae. Treat myosistis and vasculitis)
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T. Spiralis Prevention and Control
* 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
NOTE: Salting, smoking, or drying of meat DOES NOT KILL THE LARVAE of T. spiralis
OMSIM lods
