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Lab 2: Measuring Parasite Eggs, Fecal Flotation, Ascarids

Terms in this set (30)

40
100
400
1000
Measuring Parasites with Compound Microscope
Conversion Factor
_____________: Precalculated using a stage micrometer reference value
Ocular objective (10X) x nosepiece objective
Total Magnification =
1.Superimpose calibrated ocular micrometer over the egg and count the number of divisions (Ocular Units; O.U.)
2. Multiply the number of O.U. by the conversion factor (for that objective) to get µm
•35 O.U. in length at 40X (total magnification?):
•35 O.U. x 2.5 "µm" ⁄"O.U" = 87.5 µm in length
3. Scan using 10X objective, measure using 40X
•Adjust condenser
•Adjust lighting

Basically want to be as zoomed in as possible being able to see the whole organism, will usually be 40x objective
Measuring Parasites
nitrate and saturated salt solutions

F, a number of studies have shown that this procedure will detect significantly fewer parasite infections than the centrifugal flotation.

33% ZnSO4 or sugar (Because Sheather's sugar is very viscous, eggs may need more time to float to the surface. Additionally, the feces were not strained before the eggs were floated, and large fecal particles tended to float during standing flotations with Sheather's sugar.)

the salt may crystallize on the edge of the coverslip so that it will not lie flat on the slide.
Simple Fecal Flotation Procedure
When a centrifugal flotation procedure cannot be performed, sodium __________ can be used in a benchtop flotation test
T/F?
A number of studies have shown that this procedure will detect significantly more infections than the centrifugal flotation.

This technique is not recommended for _____________ flotation tests:
1. Mix several grams (a teaspoonful) of feces with the flotation solution in a cup.
2. Strain the mixture through cheesecloth or a tea strainer.
3. Pour into a test tube, pill vial, or container provided in a commercial kit. Add enough mixture or additional flotation fluid until there is a reverse meniscus on the top of the container. Place a coverslip on the fluid drop at the top.
4. Allow the flotation to stand for at least 10 minutes, remove the coverslip, place it on a slide, and examine. If the test is allowed to stand for too long, what might happen?
•Fecasol® (NaNO3 )
•Other saturated salt solutions can be used (NaCl, Epsom)

1.41
Simple Fecal Flotation
Flotation media
________________

Specific gravity is measured with a hydrometer
•Saturated NaNO3, ______________
Ascarids—Adults
___________________
Superfamily Ascaridoidea
•Among the largest nematodes
•"Roundworms"
•In small intestines
•Stout-bodies, taper at each end
•Mouth surrounded by 3 fleshy lips
•Males have ventrally curved tails
Toxocara canis
Ascarids-Adults
Superfamily Ascaridoidea—ascarids
•__________________
oUp to ~15 cm long (5-6")
oLanceolate-shaped cervical alae (more narrow)
F, the larger more developed the heavier an egg will be
T/F?
In general, the smaller less developed the heavier an egg will be
Toxocara cati
Ascarids-Adults
•_______________
oUp to ~12 cm long (3-5")
oProminent, arrow-shaped cervical alae
Ascaris suum: intestinal large roundworm
Host: Pigs (Distinct from A. lumbricoides in humans even though morphologically identical)
Site of infection: Adults in SI
Distribution: Common, pigs raised outdoors
Infection: ingestion of third stage larvae in eggs
PH:
-earthworms
-dung beetles
NO TRANSPLACENTAL OR TRANSMMARY INFECTION
PPP=6-8 weeks (eggs infective in 2-4 weeks under ideal conditions)
Pathogenesis due to migrating juveniles:
-Mechanical destruction of tissue-early infection
--initial focal hemorrhages (milk spot lesions in liver)
--respiratory distress
-hypersensitivity
--hyperemia
--edema
--eosinophilic infiltrates
-Fibrosis="milk spot" lesions
Pathogenesis/clinical signs due to adults
-interference with proper nutrition and growth
-diarrhea
-occasional occlusion or perforation
-subclinical effects-reduced growth rate and poor weight gains
Diagnosis: Patent infection
-eggs in flotations
-adults at necropsy
Diagnosis: Prepatent period
-respiratory signs in young pigs
-feeder pigs 2-5 months
Egg:
-50-70 by 40-60 micrometers
-thick pitted outer wall
-golden brown
-Adults up to 30 cm (11 inches)
Superfamily Ascaridoidea—ascarids
•______________
Ascaris suum
Superfamily Ascaridoidea—ascarids
•_______________
400x
What is the total magnification of the 𝘛. 𝘤𝘢𝘯𝘪𝘴 egg you measured using the 40x objective?
10x
40x
100x
400x
1000x
Eggs of 𝘛. 𝘤𝘢𝘵𝘪 are similar in appearance to those of 𝘛. 𝘤𝘢𝘯𝘪𝘴. The eggs have a thick-shell wall that is pitted on the surface, usually stained dark in color, and contain a single cell inside the egg in fresh feces. However, eggs of 𝘛. 𝘤𝘢𝘵𝘪 are smaller and measure 71-75 by 61-65 microns.
Morphologically, how do eggs of 𝘛𝘰𝘹𝘰𝘤𝘢𝘳𝘢 𝘤𝘢𝘵𝘪 differ from those of 𝘛𝘰𝘹𝘰𝘤𝘢𝘳𝘢 𝘤𝘢𝘯𝘪𝘴? *
𝘛. 𝘤𝘢𝘯𝘪𝘴
𝘛. 𝘤𝘢𝘵𝘪.
____________ should measure up to 12.5 cm (5 inches) and up to 7.5 cm (3 inches) for ___________
Male ascarids are usually shorter than females, have a curved posterior end, and possess spicules
How do you differentiate males and females of 𝘛𝘰𝘹𝘰𝘤𝘢𝘳𝘢 spp? *
All ascarids have 3 prominent lips.

Toxocara canis: Dog large roundworm
Host: canines
Site of infection: Adult in SI, juveniles migrate extensively
Distribution: throughout the world, very common
Lifecycle:
-Eggs + L3 ingested (eggs are infective in 2-4 weeks under ideal conditions)
PPP=3-4 weeks
-L3 hatches and migrates to liver, then lung via blood
Option 1: Mature dogs (>6 months old)
-Somatic migration of L3s dissemination via peripheral circulation to tissues where they encyst
-Pregnant bitch
-Option 1A:
--Transplacental migration of L3s to fetal liver
--neonatal pup lungs
--tracheal migration of L3s which then migrate up the bronchial tree
--Pharynx (L3s swallowed)
--Stomach (L3-L4)
--Small intestine (L4-Adults)
-Option 1B:
--Migration of L3s to mammary glands
--L3s ingested by suckling pups
--Pharynx (L3s swallowed)
--Stomach (L3-L4)
--Small intestine (L4-Adults)
Option 2:
-Puppy <5 weeks old
-tracheal migration of L3s which then migrate up the bronchial tree
-Pharynx (L3s swallowed)
-Stomach (L3-L4)
-Small intestine (L4-Adults)
Option 3:
-Mouse (paratenic host)
-somatic migration of L3s dissemination via peripheral circulation to tissues where they encyst
-dog eats mouse, larvae released
-L3s->L4->adults in the intestine of the canine host

Pathogenesis/Clinical Signs: Migrating juvenile worms
-Respiratory disease
--2-3 day old pups
--transplacental transmission
-Heavy infection of worms in small intestines
--Nursing and weaned pups
--pot-bellied pups
--tender abdomens often due to bloating
--pups will frequently whimper and cry

Adult dogs less susceptible:
-Intestinal infection with T. canis is rare in adult togs (may not be as rare as previously thought)
-Puppies spontaneously purge intestinal infections as they mature and develop immunity to T. canis

Identification: Patent infections
-Eggs in flotations
-Adults at necropsy or in vomitus
Identification: Prepatent infections
-clinical signs and age

Eggs:
-85-90 by 75 micrometers
-thick pitted outer wall
-dark
-single cell that is developing
-subspherical

Adults:
-12.7 cm (5 inches)
-lanceolate cervical alae
-prominent 3 lips

Toxocara cati: Large roundworm of cats
Hosts: Felines
Site of infection: Adults in SI, juveniles migrate extensively
Distribution: common throughout the world
Lifecycle:
-Egg+L3 ingested
-L3s hatches and invades stomach of host
Option 1: mouse (PH)
-somatic migration migrate to and encyst in body tissues)
-cat eats mouse and L3s released
-L3s enter wall of stomach or intestine
-develop into reproducing males and females
Option 2: Cat (definitive host)
Option 2A: L3s tracheal migration migrate to liver, lungs, bronchi, trachea, pharynx, stomach and small intestines
-L3s enter wall of stomach or intestine
-develop into reproducing males and females
Option 2B: Cat (DH)
L3s somatic migration dissemination to tissues where they encyst
-pregnant queen
-migration of L3s to mammary gland
L3s ingested by suckling kittens, enter mucosa of stomach
-mature to reproducing males and females

Transmission: Ingestion of infective eggs
-no age-related immunity
-all age cats susceptible
No prenatal infections
Transmammary infections-yes but not activated by suckling like T. canis
-ingestion of paratenic hosts important
PPP 2 months

Pathogenesis and Disease:
-Respiratory signs in newborn kittens are absent (no transplacental transmission)
-Nursing kittens may obtain heavy infections from transmammary transmissions if queen is infected during preganancy
-Clinical signs may include abdominal distension and distress and chronic ill thrift

Identification: Patent infections
-Eggs in flotations
-adults at necropsy or in vomitus
Identification: Prepatent infections-clinical signs and age

Eggs: 65-75 micrometers
-thick pitted outer wall
-dark
-single cell that is developing
-elliptical
Adults: 7.5 cm (3 inches)
-arrow-shaped cervical alae
-3 prominent lips
How many lips do 𝘛. 𝘤𝘢𝘯𝘪𝘴 and 𝘛. 𝘤𝘢𝘵𝘪 possess? *
These worms possess cervical alae which are on the anterior end of the worms. We will use their anterior location later in the semester to differentiate from worms that have caudal alae on their posterior end.
Both 𝘛. 𝘤𝘢𝘯𝘪𝘴 and 𝘛. 𝘤𝘢𝘵𝘪 have alae which are wing-like projections. The alae on 𝘛. 𝘤𝘢𝘵𝘪 are more prominent than those of 𝘛. 𝘤𝘢𝘯𝘪𝘴. Are the alae present on the anterior or posterior end of the worms? *
The eggs of 𝘛. 𝘭𝘦𝘰𝘯𝘪𝘯𝘢 have a thick shell, similar to that of 𝘛. 𝘤𝘢𝘯𝘪𝘴 and 𝘛. 𝘤𝘢𝘵𝘪; however, the outside shell of 𝘛. 𝘭𝘦𝘰𝘯𝘪𝘯𝘢 is smooth like a ping-pong ball versus a pitted surface like a golf ball of 𝘛. 𝘤𝘢𝘯𝘪𝘴 and 𝘛. 𝘤𝘢𝘵𝘪. The embryo inside 𝘛. 𝘭𝘦𝘰𝘯𝘪𝘯𝘢 eggs does not take up as much of the inside of the egg.

Identification: Patent infections
-Eggs in flotations
-Adults in necropsy or vomitus

T. leonina egg:
-75-85 by 60-75 micrometers
-smooth outer wall
-lighter in color
-single-celled embryo
-elliptical
-internal surface of shell wall appears wavy

T. leonina adult:
-6.4 cm (2.5 inches)
-lanceolate-shaped cervical alae
-3 prominent lips
How does the morphology of 𝘛. 𝘭𝘦𝘰𝘯𝘪𝘯𝘢 eggs differ from those of 𝘛. 𝘤𝘢𝘯𝘪𝘴 and 𝘛. 𝘤𝘢𝘵𝘪? *
𝘛𝘰𝘹𝘢𝘴𝘤𝘢𝘳𝘪𝘴 𝘭𝘦𝘰𝘯𝘪𝘯𝘢 𝗲𝗴𝗴𝘀
What is shown in the following picture?
Female 𝘈. 𝘴𝘶𝘶𝘮 measure up to ~40 cm (15.7 inches) in length.
What is the maximum length (in cm) of a female 𝘈. 𝘴𝘶𝘶𝘮? *
Male 𝘈. 𝘴𝘶𝘶𝘮 measure up to ~25 cm (9.8 inches) in length.
What is the maximum length (in cm) of a male 𝘈. 𝘴𝘶𝘶𝘮? *
Adult 𝘈. 𝘴𝘶𝘶𝘮 are found in the small intestines of infected pigs.
Where are adult 𝘈. 𝘴𝘶𝘶𝘮 located in an infected pig host? *
Eggs of 𝘈𝘴𝘤𝘢𝘳𝘪𝘴 𝘴𝘶𝘶𝘮 measure 50-70 by 40-60 µm are brownish in color, and surrounded by a thick, rough shell. They are smaller than eggs of 𝘛. 𝘤𝘢𝘯𝘪𝘴 but overall have the general appearance of an ascarid egg.
Are eggs of 𝘈𝘴𝘤𝘢𝘳𝘪𝘴 𝘴𝘶𝘶𝘮 larger or smaller than what you measured for 𝘛. 𝘤𝘢𝘯𝘪𝘴?
respiratory
What body system would you expect to be the most adversely affected by migrating juvenile 𝘈. 𝘴𝘶𝘶𝘮? *
gastrointestinal
musculo-skeletal
nervous
respiratory
urogenital
The prepatent period for this species is 6-8 weeks.
How long is the prepatent period of 𝘈𝘴𝘤𝘢𝘳𝘪𝘴 𝘴𝘶𝘶𝘮? *
Adult 𝘗𝘢𝘳𝘢𝘴𝘤𝘢𝘳𝘪𝘴 spp. have 3 lips--as do all adult ascarids.
How many lips to adult 𝘗𝘢𝘳𝘢𝘴𝘤𝘢𝘳𝘪𝘴 spp. have? *
Infection of adult 𝘗𝘢𝘳𝘢𝘴𝘤𝘢𝘳𝘪𝘴 spp. would be expected more commonly in foals as compared to mature horses.
Would you expect to find adult 𝘗𝘢𝘳𝘢𝘴𝘤𝘢𝘳𝘪𝘴 spp. in foals or adult horses? *
90 to 100 microns.
The diameter of 𝘗𝘢𝘳𝘢𝘴𝘤𝘢𝘳𝘪𝘴 spp. eggs should measure in the range of ________
Eggs of 𝘗𝘢𝘳𝘢𝘴𝘤𝘢𝘳𝘪𝘴 spp. are unembryonated in fresh feces. The 𝘗𝘢𝘳𝘢𝘴𝘤𝘢𝘳𝘪𝘴 spp. eggs must spend time in the external environment in order for third-stage larvae (the stage infective to horses) to develop.
Are 𝘗𝘢𝘳𝘢𝘴𝘤𝘢𝘳𝘪𝘴 spp. eggs embyonated (i.e., contain a larvae) or unembryonated when passed in fresh horse feces? *
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