Credit 2 Summer Semester Parasitology

Describe the egg of *Dicrocoelium dentriticum*

Small (38-45 um)

oval, asymmetrical

2 shells, operculum

embryonated with miracidium inside

dark brown colour

Cysticercus fasciolaris is larvocyst of

*Taenia taeniformis*

We diagnose protostrongylus rufescens larvae according to their tail end which is

Sharp, straight

Phase of parthenogony in development of *F. hepatica*

Inside IH miracidium develops into a sporocyst then redia then cercaria

*Oesophagostomum dentatum* form and release eggs

Medium sized

Oval, symmetrical

2 shells

Unembryonated, 8-32 blastomeres

Light grey

Methods used for intravital diagnosis of pig lung worm

Faecal flotation with breza solution

M: 50-63 μm, oval, THICK 3 shells, garland on the surface unembryonated, 1 blastomeres, brown

*Ascaris suum*

*Paramphistomum cervi* forms and releases eggs

Large

oval, symmetrical

2 shells with operculum

Unembryonated

Transparent

*Strongyloides papillosus* is

Thin, small, hair-like worm in SI of Ru and lagomorphs

*Capillaria plica* is parasite of

Car (dog, cat, fox etc)

The cystic stage of tapeworm *Echinococcus granulosa* is

Hydatid cyst

LC of digenean trematodes, what stage emerges from the egg

Miracidium

*Teladorsagia circumcincta* located in

abomasum

*Dictyocaulus filaria* in bronchi of

Sheep and goats

Strongyliform type of oesophagus

Stick shaped

Cylindrical middle part attached to bulbus

Egg of *Dipylidum caninum*

Small

Spherical

3 thick shells

Embryonated with oncosphere

Brown

What is not always present in life cycle of digeneans

redia

Describe the digestive tract of trematoda

Well developed alimentary canal with mouth, pharynx, oesophagus and 2 intestinal caeca, varies between species

Mongenea affects which species – MCQ

fish

Maritogony occurs in which host – MCQ

final host

IH of Fasciola hepatica – MCQ

*Lymnea* snail

name the parasite and describe the life cycle

*Dicrocoelium dendriticum*

* embryogony


1. adult releases embryonated egg with **miracidium**
2. operculum opens and miracidium released to find first IH (land snail)
* parthenogony


1. miracidium penetrates into body cells of IH, releases cilia and forms **mother** **sporocyst**
2. **daughter sporocysts** are formed from germinal cells
3. inside each daughter sporocyst forms at least 40 cercaria
4. cercaria are released to the environment in slimy secretion 3-5 months after infection of snail
5. boluses/slime balls containing approx. 6000 cercaria are ingested by second IH (ant)
* cystogony


1. after ingestion, cercaria penetrate wall of digestive system of and and pass into abdominal cavity and encyst to form metacercaria


1. usually 2 cercaria migrate to the neural ganglion so the ant migrates and attaches to plants and stay there via spasm
* maritogony


1. ants containing metacercaria are ingested by DH
2. juvenile form migrates through small intestine to ductus choledochus and to bile ducts, where they reach sexual maturity in 2-3 months

Name the egg in cyclophyllida species – MCQ

oncosphere

Lung worms of small ruminants – list

*Dictyocaulus filarial*

*Muellerius capillaries*

*Protostrongylus rufescens*

*Cystocaulus ocreatus*

*Neostrongylus linearis*

What species does *Hymenolepis nana* infect – MCQ

mouse

*Ascaridia galli* – life cycle – MCQ

direct or indirect

direct

IH of cysticercus tenuicollis – MCQ

livestock (ruminants, pigs, etc.)

Describe the different stages of pseudopyllida

Coracidium 🡪 procercoid 🡪 plerocercoid

Definition of oviparous

female lays unembryonated eggs

Picture of horse egg – give name and write the 5 characteristics

Parascaris equorum

medium (90-100 μm)

almost spherical

three thick shells with outer pitted coat

single homogenous blastomere

brownish

Picture of 2 eggs from dog – give name and write 5 characteristics

A. *Toxicara canis*

medium (75-90 μm)

subglobular with thick pitted shells

dark brown

\
B. *Toxicara leonina*

medium (75-85 μm)

subglobular with thick pitted shells

almost colourless

Picture of mouse egg – give name and write the 5 characteristics

*Aspiculuris tetraptera*

medium (70-100 x 30-50 μm)

elliptical, symmetrical

two thin shells

unembryonated (morula)

transparent

*Strongyloides westeri* host – MCQ

horse

Method of intravital diagnosis of pig lungworms

ovoscopy

What does *Macracanthorhynchus hirudinaceus* belong to – MCQ

Acanthocephala

Nematodes of sheep large intestine

*Chabertia ovina*

*Skrjabinema ovis*

*Skrjabinema caprae*

Cestode body segments are called?

proglottids

What stage is not always present in the life cycle of Digeneans?

redia

Who is the IH of Taenia solium?

pig

The life cycle of *Toxascaris leonine* is: (direct/indirect)

Ascaridoid direct

What is the site of *Heterakis gallinarum*?

Large Intestine – Caecum of Birds

What is the cyst of Echinococcus?

Hydatid

In Pseudopyillidea, what stage comes after the adult?

coracidium → Procercoid → plerocercoid

How is the stage inside arthropods in Cyclophyllidea called?

Metacestode - Cysticercoid

Strongyloides westeri is a parasite of

Horse and donkey

*Toxocara vitullorum* is a parasite of?

Calf

How many moults and larval stages are there in Nematodes?

4 moults and 4 larval stages

What hatches from a Pseudophyllidean egg?

Coracidium

Oxyurida order – spp. In horses:

Oxyuris equi

Monogenea is parasite of :

fish

Round worms in pigs (spp.):

*Ascaris suis*

*Strongyloides ransomi*

*Trichuris suis*

*Ascarops strongylida*

*Metastrongylus pudendotectus*

*Hyostrongylis rubidus*

*Oesophagostomum dentatum*

*Dicrocoelium dendriticum* IH

terrestrial snails and ants

*Taenia pisiformis* IH

hares and rabbits

*Taenia saginata*: site, IH, DH

IH: cattle - organs and muscles

DH: humans - small intestine

What structure is on the scolex of Pseudophyllida?

bothria

Which stage invades the DH in Trematoda (infective stage)?

metacercaria

Monoxeonous is:

with only 1 host

Direct life cycle is:

no IH or vectors

Embryogony in Cyclophyllidae is in:

DH (embryonated when leave DH)

Which parasite has hyatid cyst?

*Echinococcus granulosus*

What is the larval stage in Cyclophylidae?

metacestodes (cysticercus, coenurus, cysticercoid, echinococcus, tetrathyridium, strobilocercus)

Life cycle of *Toxascaris leonina* is (direct/indirect)?

direct

In Cyclophyllidae, which stage precedes the adult stage?

metacestode larval form

*Toxocara canis*: location and host

host: dogs and foxes

paratenic host: many animals

location: small intestine

*Diphylidium canium*: location and hosts

IH: fleas (*Cetenocephalides canis)*, lice (*Trichodectes canis*)

DH: dog, cat, rarely man

location: small intestine

*Taenia ovis*: location, host, metacestode

IH: sheep, goat

metacestode: *cysticercus ovis* (muscles)

DH: dog, fox, wild canids

location: small intestine

Eggs 4μ are what size?

small

Species of large Stongyles in horses

*S. vulgares*

*S. edentatus*

*S. equinus*

Life cycle of *Dictyocaulus sp.* in cow

1. female worms are ovoviviparous laying egg containing fully developed larva in lung
2. L1 hatch in bronchus
3. L1 migrate up trachea, are swallowed and passed in faeces
4. L1 moult to L3 in environment
5. they leave the faeces to the herbage, whether by own motility or through agency of fungus *Pilobolus* and are ingested
6. L3 penetrates the intestinal wall to the mesenteric lymph node where it moults to L4
7. L4 travel via lymph and blood to the lung and enter the alveoli
8. final moult occurs in bronchioles a day later
9. young adults move to bronchi and mature

What eggs are in floatation method in pig faeces?

*Ascaris suum*

*Oesophagostomum dentatum*

*Trichuris suis*

*Metastrongylus sp.*

What eggs can we find in sedimentation/floatation method of ruminant faeces?

1. sedimentation


1. *Fasciola hepatica*
2. *Dicrocoelium dentriticum*
3. *Paramphistomum cervi*
2. floatation


1. fam. Trichostrongylidae: *Trichostrongylus, Cooperia, Haemonchus, Theladorgasia*)
2. *Strongyloides papillosus*
3. *Nematodirus sp.*
4. *Moniezia expansa, M. benedeni*
5. *Trichuris ovis*
6. *Oesophagostomum sp.*
7. *Toxocara vitulorum*
8. *Capillaria bovis*

Head of Cestoda are called:

scolex

Heteroxenous life cycle means:

more than one host

Life cycle of *Syngamus trachea*

DH: domestic fowl and game birds (pheasants)


1. eggs escape under the bursa of the male
2. carried up trachea in mucus and swallowed, then passed in faeces
3. L3 develops within the egg
4. infection may occur in 3 ways


1. ingestion of L3 in egg
2. ingestion of hatched L3
3. ingestion of transport host
5. penetrate the intestines of DH and travel to the lung via blood
6. two parasitic moults take place in the lung in 5 days
7. copulation occurs in trachea or bronchi around day 7

IH of *F. hepatica*

snails of genus *Lymnea*

Metacestode of *Taenia saginata* is:

*Cysticercus bovis*

Non-microscopic method of detecting *Oxyuris* in horse is:

perianal swab/scraping

Life cycle of *Taenia pisiformis*. Host and name of larval stage

IH: rabbits and hares

DH: dog, fox, other canidae

larval stage: *Cysticercus pisiformis*


1. rabbit ingests egg, which hatches in small intestine
2. penetrates the intestinal wall and travel to the liver via the blood
3. develops in liver for 2-4 weeks
4. migrates to the peritoneal cavity and attaches to viscera
5. when DH ingests IH, the cysticercus attaches to small intestinal wall by its scolex
6. gravid proglottids detach and pass in faeces

Tapeworms of ruminants are Anoplocephalidae

Monezia expanza/benedeni

Larval stage of *Taenia hydatigena*

Cysticercus tenuicollis

Parampistomum is located in

Mainly fore stomachs of ruminant

Adult: rumen and reticulum

Larva: Duodenum and abomasum

Common name of cestodes

Tapeworms

L.C of Echinococcus spp

1. gravid segements are excreted in faeces of dog
2. they are very resistant to climatic conditions
3. eggs are spread by wind or flies
4. eggs are ingested by IH (human, domestic and wild animals)
5. embryos are disseminated via blood and carried to various tissues and organs, and form hydatid cysts
6. hydatid cysts are lined with germinative layer
7. produces broad capsules that consist of several scolices
8. part of germinative epithelium may occasionally form daughter cysts by budding
9. final host acquire infection by ingesting viscera-containing cysts

Which muscles are the predilection sites for nematode detection (trichinella)

Adults: small intestine

Larvae: striated muscles, diaphragm, intercostal and masseter muscles

Platyhelminths common name is

Flatworms

Alvelocosis is caused by:

Echinococcus multiocularis

Taenia ovis: IH, site, metacestode

• IH sheep - muscle

• FH carnivore - small intestine

• Cysticercus ovis

Oesophagostomum is diagnosed by?

Flotation method

Tapeworms of horses

1. *Anoplocephala perfoliata*
2. *Anoplocephala magna*
3. *Paranoplocephala mamillana*

Which worms can we find in pig faeces?

Strongyloides ransomi

Hyostrongylus rubidus

Oesophagostomum

Metastrongylus

Ascaris suum

Trichuris suis

Macracanthorhynchus hirudinaceus

1st IH of *Dicrocoelium*

land snails-(Helicella spp.)

Life cycle of Metastrongylus.

1. Egg in environment hatches
2. Larva ingested by IH earthworm
3. Molts L2 -> L3
4. FH pig ingests earthworms
5. Travel to lymph nodes and molt
6. Reach lungs and molt to adults

Toxocara canis (location and hosts)

small intestine of dog and cat

*Dipylidium caninum* in which animal?

1. IH: fleas and lice larvae as cysticercoids
2. DH: dog

Diagnosis methods in ru faeces.

sedimentation, larvoscopy (baerman or vajda) or flotation

Which size of egg is 45μm?

Small

What methods do we use in intravital diagnosis?

1. coprological exam (larvoscopy, sedimentation, flotation)
2. anal smears
3. serological
4. clinical

What is the larval stage in cyclophylidae:

Metacestode in IH


1. Cysticercus
2. Cysticercoid
3. Coenurus
4. Strobilocercus
5. Echinococcus (Hydatid cyst)
6. Tetrathyridium

IH in Cyclophyllidae:

either vertebrate or invertebrate

Forms metacestode in IH (larval stage)

Taenia saginata: location, IH and what it forms in it and DH

humanLocation: small intestine

IH: cattle - forms Cysticercus bovis in muscle

DH: human