NEMATODES (ROUNDWORMS) Flashcards
Maria, a 5-year-old girl, presented to a local clinic complaining of diarrhea and gastrointestinal pain and bleeding.
Patient history revealed that Maria recently emigrated to the United States from Puerto Rico. The physician on duty ordered a series of stool samples for O&P. Barrel-shaped
structures, as noted below, that appeared to have plugs at each end were seen on the direct wet preps, concentrated wet preps after performing a zinc sulfate flotation method,
and permanent stains.
- What is the scientific name and morphologic form of the parasite present in Maria’s samples?
- What is the common name for this parasite?
- How did Maria contract this parasite?
- Which disease state is associated with this parasite?
- Which morphologic form of this parasite may be visible
on microscopic examination of the intestinal mucosa of
this patient?
- Trichuris trichiura egg.
- Whipworm.
- Ingestion of infective eggs.
- Trichuriasis; whipworm infection.
- Adult worms.
The junvenile stage of developing nematode worms is referred to as?
Larvae
Adult nematodes are never recovered in clinical
samples. True or False?
False
Class of nematode that contains caudal chemoreceptors of round worms. The organ for the detection of food caudal chemoreceptors
Phasmid
Species that parasitize the small intestine
“CASHTs”: Capillaria, Ascaris, Strongyloides, Hookworms, Trichenella spiralis
Species that parasitize the large intestine
“ET”: Enterobius, Trichuris
Species that parasitize the tissues
Wuchereria bancrofti, Brugia malayi, Loa Loa, Dracunculus medinensis
Species that causes larva migrans in man
Ancylostoma braziliense, caninum and Toxocara
Class of nematode that lacks phasmids or caudal chemoreceptors
Aphasmids
Most primitive group of nematodes
Aphasmids
Do aphasmids have a sensory bristles or papillae? True or False
False
Common name of Trichinella spiralis?
Trichina Worm
Trichinella spiralis
Infective stage?
Main Habitat?
Ova
a. Biopsies of these larvae often reveal a?
b. What is its notable features?
Adult Female
a. Notable features of a female adult T. spiralis?
b. Is the female adult viviparous?
Adult Male
a. Notable features of a male adult T. spiralis?
Laboratory Diagnosis
a. method of choice for recovery of the encysted larvae
b. Other laboratory findings may also serve as indicators for disease
c. In correlation to CC, what enzymes are elevated?
d. A test that uses antigen prepared from Trichinella larva
e. A test that uses albino rats
Life Cycle Notes
a. Human infection with T. spiralis is the result of accidental human infection with a parasite whose normal host is?
b. Human infection is a dead-end infection?
Disease: Trichinosis, Trichiniasis, Trichinelliasis
a. generalized inflammation of duodenal and jejunal mucose, malaise, nausea, diarrhea, and abdominal cramps
b. fever, facial edema (particularly the eyes), pain, swelling and weakness of the involved muscle
c. begins at about the end of the 3rd week; cyst wall subsides; the larva itself will calcify
-Encysted larva
-Small intestine, skeletal muscles (coiling up in the muscle fibers and becoming encysted)
Ova
-Distinctive inflammatory infiltrate
-coiled; Inflammatory infiltrate
present around nurse cell, spear-like burrowing tip at its tapering anterior end
Adult Female
-Blunt, round posterior end; single ovary with
vulva in anterior fifth of body
- Yes it is capable of laying live larvae
Adult Male
-single testis, curved posterior end with two rounded appendages
Laboratory Diagnosis
-Examination of the affected skeletal muscle/Muscle Biopsy
-eosinophilia and leukocytosis
-Elevated serum muscle enzyme levels, such as lactate dehydrogenase, aldolase, myokinase and creatinine phosphokinase aid in T. spiralis diagnosis.
-Bachmann Intradermal Test
-Beck’s Xenodiagnosis
Life Cycle Notes
- an animal (zoonosis)
-yes
Disease
-Intestinal invasion
- Muscle invasion
-Convalescence
The specimen of choice for the identification of Trichinella spiralis is which of the following?
A. Cerebral spinal fluid
B. Stool
C. Skeletal muscle
D. Urine
C
The diagnostic stage of Trichinella spiralis is which of the following?
A. Encysted larvae
B. Cysts
C. Eggs
D. Adult worms
A
Trichinosis is acquired via which of the following?
A. Swimming in contaminated water
B. Consuming contaminated water
C. Ingestion of contaminated food
D. Inhalation of contaminated air droplets
C
Common name of Capillaria philippinensis
Pudoc worm / mystery disease
Capillaria philippinensis
Infective stage?
Intermediate Host?
Developmental Stage:
A. Ova
> resembles “________” appearance
B. Atypical female
> the ______ eggs in utero are arranged in the ________ (Oviparous)
C. Typical female
> the _____ eggs in utero are arranged in _____
(Larviparous); does it cause autoinfection?
D. Male
>characterized by the presence of?
Disease: Capillariasis or Mystery Disease
a. what is Borborygmus/ Borborygmi?
Laboratory Findings
a. Shows a?
Diagnosis
a. Diagnosis is based on finding characteristic
eggs in the feces by?
Drug of choice
a. The drug of choice for the treatment
of intestinal capillariasis is
-Encysted larva/3rd stage
-glassfish, “bagsit”, “bagsang”, “ipon”
Developmental Stage:
A. Ova
- pale yellow with moderately thick striated shell, and with flattened bipolar plugs; resembles “peanut-shaped” appearance
B. Atypical female
-8-10 eggs in utero; single row
C. Typical female
-40-45 eggs; 2-3 rows; autoinfection
D. Male
-a chitinized spicule and a long spicule sheath extending beyond the length of the worm
Disease
-Gurgling stomach; diarrhea with constipation
Laboratory findings
-protein-losing enteropathy and hypoalbuminemia; malabsorption of fats and
sugars; decreased excretion of xylose; low serum potassium, sodium and calcium; and high levels of immunoglobulin E.
Diagnosis
-by direct smear or wet mount, as well as by stool concentration methods.
Drug of choice
-Albendazole, Mebendazole
Epidemiology
-Tagudin Ilocos Sur, Thailand
Drug of choice:
a. Protozoan?
b. Filarial?
c. Fowleri, acanthamoeba?
d. Nematode?
a. Mitronedazole
b. DEC
c.
d. Albendazole, Mebendazole
Common name of Capillaria hepatica
Capillary liver worm
Capillaria hepatica
Infective stage?
Main habitat?
Developmental Stages
a. Ova
- what are the shaped of its eggs?
-Outer shell
-Embryonated ova
-Liver of the host
Developmental Stages
a. Ova
- lemon shaped eggs
-Pitted like golf ball
Common name of Trichuris trichuria
Whipworm
Trichuris trichuria
Infective stage?
Main Habitat?
Ova
a. resembles a?
b. Shell Smooth; yellow-brown color because of?
Adult
a. The posterior end of the adult T. trichiura is large and resembles that of a?
b. It has a coiled posterior portion
Laboratory Diagnosis
a. Specimen of choice for the recovery of T.
trichiura eggs is?
Embryonated Ova
Cecum and appendix
Ova
-Barrel/football-shaped, Japanese lantern; A prominent hyaline polar plug is visible at each end.
-bile stained
Adult
-Whiplike (3/5 is attenuated)
-Male
Laboratory Diagnosis
-Stool
Trichuris trichiura eggs are characterized by the presence of which of the following?
A. Triple-layer cell wall
B. Flattened side
C. Hyaline polar plugs
D. Prominent cytostome
C
Of the following choices, the best laboratory diagnosis technique for the recovery of Trichuris trichiura eggs is which of the following?
A. Zinc sulfate flotation
B. Modified acid-fast stain
C. Ethyl acetate concentration
D. Wright-Giemsa stain
A
Children infected with Trichuris trichiura commonly suffer from:
A. Mental confusion
B. Hemoglobinuria
C. Severe anemia
D. Rectal prolapse
D
Common name of Ascaris lumbricoides
Giant intestinal roundworm
Most common intestinal roundworm
Asacaris lumbricoides
Ascaris lumbricoides
Infective stage
Main habitat
Mechanical Vector
Developmental Stages
a. Ova
-Unfertilized ova is?
-Layer that is absent in old specimens
-Fertilized ova is?
-3 layers:
i. outermost mamillated layer with a tanning action
ii. chitinous layer; secretory product of the egg
iii. fertilization membrane; protects the inner embryo
b. Fertilized egg
- A thick nitrogen-containing polysaccharide coating called? also known as a shell, is
sandwiched in between the embryo and mammillated albuminous material (corticated)
c. Adult
- white, creamy, or pinkish yellow when freshly expelled and resembles?
- head is provided with ______ lips which are finely denticulated
-The adult female resembles a _______ in thickness.
Diseases: Ascariasis, Dooryard or Backyard Infection
-pneumonia like with infection of Ascaris lumbricoides
Embryonated Ova
Lumen of the SI
Cockroaches
Developmental Stages
a. Ova
-long and narrower/oblong
-Albuminoid layer
-Broadly ovoidal and thick/Circle
-i. Albuminous layer
ii. Chorionic/true shell
iii. Vitelline layer
b. Fertilized egg
- Chitin
c. Adult
-earthworm
-with three conspicuous lips
-pencil lead
Diseases
-Loeffler’s syndrome
Ascaris lumbricoides
Stool examination may give negative results due to the following:
-Infection is still early (worms are still immature)
-During larval migration through the bloodstream
-Male worms are the only present in the intestine
keep in mind
Individuals contract Ascaris lumbricoides via which of the following?
A. Inhalation
B. Insect bite
C. Ingestion
D. Inappropriate sexual practices
C
The term that describes the lack of an outer mammillated albuminous coating is called which of the following?
A. Unfertilized
B. Fertilzed
C. Corticated
D. Decorticated
D
The specimen of choice for the recovery of Ascaris lumbricoides eggs is which of the following?
A. Stool
B. Gallbladder biopsy
C. Urine
D. Sputum
A
Kato thick or Kato Katz
a. For screening purposes (Quali)
b. for egg count (Quanti)
a. Kato thick
b. Kato katz
Unholy trinity
HAT (Hookworms, Ascaris, Trichuris)
Human Hookworms
Common Name of N. americanus
Common name of A. duodenale
A. ceylanicum
-American murderer/American hookworm/New
World Hookworm
-Old World Hookworm
Animal Hookworms
Common name of A. braziliense
Common name of A. caninum
- cat hookworm
- dog hookworm
IDA (capable of depriving individual with Fe) is commonly associated with?
Vit. B12/Pernicious Anemia is commonly associated with?
-Hookworms
-D. latum (Cestodes)
Hookworm
Ova
-how many cell stage when passes in the feces (surrounded by a clear zone)
-Sensitive for?
Feeding stage (active metabolism)?
-short and stout
-has a long narrow buccal cavity
-flask-shaped esophagus
-very small genital primordium
Non-feeding stage; infective stage?
-mouth is closed with a protecting sheath
-longer and slender with a pointed
posterior end
Buccal Cavity
i. 1 pair of semilunar cutting plates
ii. 2 pairs of fused ventral teeth
iii. 3 pairs of ventral teeth
iv. 1 pair of larger outer teeth and 1 pair of very inconspicuous median teeth
Mode of Transmission?
Diseases
Due to larval stage:
a. Intense itching, edema and erythema and later papulovesicular eruption
b. Creeping eruption aka ?
-“Serpiginous tunnel” in the stratum germinativum of the skin
c. causes pulmonary lesions
The primary means for laboratory diagnosis of
hookworm is the recovery of the eggs?
-4-8
- sensitive for disintegration
-RHABDITIFORM LARVA
-FILARIFORM LARVA
i. N. americanus
ii. A. duodenale
iii. A. caninum
iv. A. brazilliense
-MOT: skin penetration
Diseases:
a. Ground itch (aka Coolie itch or Dew itch)
b. aka Cutaneous Larva Migrans/Plumber’s itch/Duck hunter’s itch
- “Serpiginous tunnel” in the stratum germinativum of the skin
c. Wakana disease
-Stool samples
Blood loss:
N. americanus
A. duodenale
N. americanus: 0.03-0.05 ml/day
A. duodenale: 0.16-0.34 ml/day
Medium used in Harada Mori culture technique
-if nasa taas?
-if nasa baba?
Distilled H2O
-Strongy
-Hookworm
This adult hookworm is characterized by a buccal cavity that contains teeth.
A. Ancylostoma
B. Necator
C. Both Ancylostoma and Necator
D. Neither Ancylostoma nor Necator
A
Individuals contract hookworm via which of the following?
A. Contaminated water
B. Skin penetration
C. Insect bite
D. Contaminated food
B
Which of the following are appropriate Ascaris lumbricoides prevention and control strategies?
A. Proper water treatment
B. Appropriate food handling
C. Use of insect repellent
D. Proper sanitation practices
D
Common name of Strongyloides stercoralis
Threadworm
Strongyloides stercoralis
Habitat?
Developmental stages:
a. Ova resembles a?
- not found in feces except?
b. Adult has no teeth, no cutting plates but bears a?
Diseases
Laboratory Diagnosis
-Stool concentration with _______ has successfully recovered these eggs
Treatment
-both an ovicidal & larvicidal
Upper small intestine (Duodenum)
Developmental stages:
a. chinese lantern
- diarrhea and hyperistalsis
b. crown of chitinous, leaf-like processes
Disease: Cochin-china diarrhea
Laboratory Diagnosis:
-Zinc sulfate
Treatment
-Thiabendazole
This diagnostic stage of Strongyloides stercoralis is best seen in stool using fecal concentration techniques:
A. Eggs
B. Rhabditiform larvae
C. Filariform larvae
D. Adult worms
B
The life cycle of Stronglyoides most resembles that of which of the following?
A. Pinworm
B. Whipworm
C. Hookworm
D. Threadworm
E. Human roundworm
C
The two clinical symptoms most commonly associated with Trichinella spiralis are which of the following?
A. Constipation and abdominal pain
B. Vomiting urticaria
C. Diarrhea and vomiting
D. Abdominal pain and diarrhea
D
Enterobius vermicularis
* Ova:
a. Developing larva surrounded by
- Adult:
- Expansion of cuticle called the “________ alae or _________ wings”
- It has an oral end and ___ lips
- What is the shaped of the esophagus?
a. Female
- Tail is _____ resembles _________
- Specimen of choice: _________
- flattened on one side (D-shaped)
a. conspicuous double-layered, thick-walled colorless shell
*Adult
- Cephalic alae/ lateral wings
- oral end, 3 lips
- Hour glass shaped esophagus
a. Adult Female: Tail is pointed resembles pin head
- Specimen of choice: Cellophane tape preparation
Common name of Enterobius vermicularis
Pin/Seat/Society Worm
True or False:
It is believed that E. vermicularis may be responsible for the transmission of Dientamoeba fragilis
True :)
The most likely individual to contract pinworm infection is(are) a(an):
A. Older adult
B. Child
C. Adult prisoner
D. Military personnel
B
The morphologic forms recovered in cases of pinworm infection are which of the following?
A. Eggs and adult females
B. Adult males and females
C. Eggs and larvae
D. Larvae and adult males
A
Enterobius vermicularis:
a. Main Habitat
b. Infective Stage:
c. Synonym name
d. Nocturnal or diurnal perianal itching?
e. Give 3 diagnosis for E. vermicularis
a. Cecum & Appendix
b. Embryonated Ova
c. Oxyuris vermicularis
d. Nocturnal 10pm - 2am
e. Graham scotch tape, NIH Swab technique, Schuffner & Swelling Rebel Method
Enterobius vermicularis is the most contaminant found in urine
TRUE
This species causes Visceral Larva Migrans
Toxocara species
Toxocara Species:
a. Infective Stage
b. Synonym names:
c. Host
d. Are Humans the accidental host?
e. Paratenic Host
f. Known as Dog Ascarid
g. Known as Cat Ascarid
h. Habitat
a. Embryonated ova
b. Ascaris mystax, Belascaris mystax, Belascaris cati
c. Dogs and Cats
d. Yes
e. Ducks & Rabbits
f. Toxocara cani
g. Toxocara cati
h. Small Intestine
What are the 2 major forms of Toxocara species?
Ocular Larva Migrans (OLM)
Visceral Larva Migrans (VLM)
Can Ocular Larva Migrans causes Blindness?
Yes
Toxocara egg:
a. Color
b. Spherical to slightly _______ shaped, thick shelled and has a _________ surface
c. Is T. cati is slightly larger than T.canis?
a. Gold
b. Pear shaped; pitted surface
c. No. T. canis is slightly larger than T. cati
TRUE OR FALSE:
I. The larvae of Toxocara species do not develop into the adults in human, a stool examination would not detect any Toxocara eggs
II. Presumptive diagnosis of Toxocara is OLM and VLM
I. True
II. True
Mimics the eggs of Hookworms
Trichostrongylus Species
Are Trichostrongylus Species considered as zoonotic infection? And are they herbivores?
Yes
Enumerate the human infections of Trichostrongylus Species
T. colubriforms
T. orientalis
T. axei
T. brevi
Trichostrongylus Species:
a. T. tenuis - infects
b. T. axei - also known as
c. T. colubriforms - also known as
d. TRUE/ FALSE:
- These are the less frequent Trichostrongylus species (T. probolurus, T. vitrinu)
a. poultry
b. Stomach hairworm
c. Bankrupt worms
d. True
TRUE OR FALSE:
The eggs of Trichostrongylus species are similar to Hookworm eggs
TRUE
Common name of Angiostrongylus cantonensis
Rat Lungworm / Rodent lungworm
Angiostrongylus cantonensis:
a. Synonym
b. Definitive Host
- What is the IH?
c. Main Habitat
d. Infective Stage:
e. Its diagnosis has a moderate to high eosinophlic count in the spinal fluid
a. Pulmonema cantonensis
b. Rats
- IH: Achatina fulica
c. Lungs
d. 3rd stage larva
e. Brain dyscrasia
Angiostrongylus cantonensis Ova
1st or 3rd stage larva
a. Distinct dorsal minute notch
b. 2 well developed chitinous rods with expanded knob like tips
a. 1st
b. 3rd
Angiostrongylus cantonensis: Adult Worms
a. Female is described to have a transparent cuticle as _________ pattern
b. Male has a well developed caudal bursa which is ________ shaped and single lobed
a. barber’s pole
b. kidney shaped
The transmission of Angiostrongylus cantonensis is through the ingestion of raw mollusks
TRUE
It is the common gastrointestinal parasite of marine mammals with Pseudoterranova
Anisakis Species
This causes Herring Disease
Anisakis Spp
Anisakis species:
a. Infective Stage
b. Enumerate the Anisakis simplex complex
c. Enumerate the Pseudoterranova decipiens complex
e. Treatment
a. 3rd stage larva
b. A simplex sensu stricto, A pegreffii, A. berlandi
c. P. decipiens sensu stricto, P. azarasi, P. cattani
d. ALBENDAZOLE
Common name of Dracunculus medinensis
Guinea worm
Fiery serpent of the Israelites
Medina worm
Serpent worm
Dragon worm
Dracunculus medinensis:
a. Enumerate the disease caused by this parasite
b. Habitat
c. Life Span:
d. Infective Stage:
e. Diagnostic Stage
f. Treatment
a. Dracunculiasis/Dracontiasis/ Dracunculosis
b. Cutaneous & Subcutaneous
c. 12-18 months
d. 3rd Larval stage
e. Rhabditiform larva
f. Mebendazole, Niridazole, Thiabendazole
The diagnosis of calcified worm found in Dracunculus medinensis is by
Xray
The two morphologic stages present in the Dracunculus medinensis are which of the following?
A. Eggs and larvae
B. Larvae and adults
C. Eggs and adults
D. None of the above
B.
The specimen of choice for the recovery of Dracunculus medinensis is which of the following?
A. Infected ulcer
B. Skeletal muscle
C. Stool
D. Blood
A
When humans contract Dracunculus medinensis, the parasite’s life cycle ceases to continue
A. True
B. False
C. Unable to determine
B
Common Names:
1. Trichinella spiralis
2. Trichuris trichiura
3. Enterobius vermicularis
4. Dracunculus medinensis
5. Necator
americanus
- Trichina worm
- Whipworm
- Pinworm
- Guinea worm
- Hookworm
The eggs of which group of nematodes are indistinguishable?
A. Whipworm and trichina worm
B. Hookworm and threadworm
C. Guinea worm and roundworm of man
D. Pinworm and whipworm
B
Once inside a human, these two nematodes take up residence outside the intestinal tract.
A. Enterobius vermicularis and Strongyloides stercoralis
B. Necator americanus and Ancylostoma
duodenale
C. Dracunculus medinensis and Trichinella spiralis
D. Trichuris trichiura and Ascaris
lumbricoides
C
Common Diseases
1. Roundworm of
man
2. Whipworm
3. Hookworm
4. Pinworm
5. Guinea worm
- Ascariasis
- Trichuriasis
- Ancylostomiasis
- Enterobiasis
- Dracunculosis
These two nematodes are similar in that they are both suspected of being transport hosts of Dientamoeba fragilis.
A. Trichinella and Dracunculus
B. Necator and Trichuris
C. Strongyloides and Ancylostoma
D. Ascaris and Enterobius
D
The eggs of these two nematodes are never to rarely seen in stool samples.
A. Trichina and threadworm
B. Whipworm and roundworm of man
C. Guinea worm and pinworm
D. Threadworm roundworm and
hookworm
A
Egg Morphology
1. Flattened on one
side
2. Obvious albuminous
coating
3. Surrounded by a nurse cell
4. Thin shell surrounding embryonic cleavage
5. Polar plug on each end
- E. vermicularis
- A. lumbricoides
- T. spiralis
- Ancylostoma
5.Trichuris trichuria
Which of these parasites are contracted via skin penetration?
A. Enterobius, Necator, Dracunculus
B. Ascaris, Trichinella, Ancylostoma
C. Trichuris, Strongyloides, Enterobius
D. Ancylostoma, Strongyloides, Necator
D
