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Parasitology II > Test 1 --> Lifecycle of flukes, intermediate hosts, Fasciolosis, Dicrocoeliosis, Paramphistomatidosis > Flashcards

Test 1 --> Lifecycle of flukes, intermediate hosts, Fasciolosis, Dicrocoeliosis, Paramphistomatidosis Flashcards

1
Q

What is Trematodes?

A

Flukes:

  • unsegmented parasitic worms
  • With 2 suckers
  • Branching intestinal canal.
  • Their larvae always develop in molluscan hosts first
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2
Q

What is the causative agent in the Liver Fluke?

A

Fasciola hepatica

Causing Fasciolosis

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3
Q

In which species does the Fasciolosis occur in?

A

Ruminants

worldwide distribution

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4
Q

Where does the Fasciola Hepatica Live?

A

Biliary ducts of the liver.

It lives in enlarged and dilated biliary ducts of
liver.

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5
Q

What is the morphology of the Fasciola Hepatica?

A
  • Flat,
  • 2-3 cm long,
  • leaf-like,
  • slowly moving,
  • whitish or grayish brown animals
  • 2 suckers (Tip of head and ventral side)
  • Body filled with genitals and many branches of intestinal caeci.
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6
Q

What is this

A

Fasciola Hepatica

Two preserved specimens of lives fluke. Darker branches
of intestine filled with digested blood can be seen on the
dorsal surface. Above the small ventral sucker a penis-like
copulatory organ erects to the surface.

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7
Q

Lifecycle of the Liver Fluke

A
  1. Adult worms produce large (120-150 µm-s long) eggs which are shed with host’s feces.
  2. Zygote containing egg develops to a ciliated larva (MIRACIDIUM) in water usually within 2 weeks
    3.** Larva hatches and swims in water to find and penetrate into a freshwater snail
    4.In the     body of snail** (=intermediate host) the first larva turns to a bladder-like sporocyst.
  3. In the cavity of sporocyst a third larval form develops by asexual budding, so called paedogenesis.
  4. The **third larval **form, called RADIAE (singular: redia) has a mouth and a blind sac of intestine and actively consume the tissues of the snail host. Depending on the size and nutrition of the snail, from the first generation of mother rediae several generations of daughter rediae can come into being inside same intermediate host.
  5. After some time, the next larval stage, the CERCARIA develops inside the body of a redia. Cercariae have **long tail **and two suckers.
  6. After rain the mudflat where the snails live, becomes wet and cercariae actively swarm out of the snail and swim for some minutes to find solid surface.
  7. Cercariae attach themselves to vegetation, shed their tail and encyst as METACERCARIA.
  8. After ingestion by the final host (mechanical removal of outer cyst wall by mastication, inner cyst wall by enzymes of intestine) the juvenile fluke (marita) penetrates the intestine and migrates to the liver via abdominal cavity.
  9. Migration in the liver parenchyma takes 4-6 weeks.
  10. Settling and reaching maturity in biliary ducts. (Praepatent period is approx. 10 weeks.)
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8
Q

What is the Praepatent period in the Liver fluke?

A

Praepatent period is approx. 10 weeks

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9
Q

Lifecycle Liver Fluke

A

**Life cycle of Fasciola. **
1: mature worm
2: eggs with zygote & miracidium
3: free miracidium
4: sporocyst, redia & cercaria in snail
5: free cercaria
6: metacercaria

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10
Q

What is this?

A

Non-embryonated egg of Fasciola as we can observe it in fresh feces. The eccentric zygote is surrounded by a finely granulated yolk.

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11
Q

What is the intermediate host in Fasciola?

In Europe

A

Galba Trunkatula

(Radix, Pseudosuccinea, Lymnaea spp.)

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12
Q

Information about the Galba Truncatula

A
  • Brownish, elongated, fragile shell.
  • Mud dweller
  • Live along the shores of shallow lakes or rivers and streams.
  • They breathe air!
  • Amphibious snails - can live outside water
  • Dark grey body, and the body whorls of shells are similar to a coiled stair
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13
Q

Amphibious snails living in the same biotope. Distinguish between the two

A
  • Galba truncatula has dark grey body, and the body whorls of shells are similar to a coiled stair
  • Succinella oblonga that lives in same place has whitish body and its whorls are flattened.
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14
Q

Which snails is on the picture? Are they a intermediate host for Fasciola Hepatica?

A

Shells of snails that live in same habitats on meadows:
* **Radix labiata **(on the left) Sometimes host for Fasciola
* Galba truncacula (in the middle) Most common host for Fasciola
* Succinella oblonga (on the right) NEVER hosts for Fasciola*

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15
Q

What is shown on the picture?

A

A native cercaria of **Fasciola hepatica.
Original size of it is as big as a pinpoint.
Only its dark head **develops to a walled metacercaria.

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16
Q

Primary habitats are not the sources for the
dangerous level of fasciolosis.

True or false?

A

TRUE
Primary habitats are not the sources for the
dangerous level of fasciolosis.

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17
Q

Where does the main source of heavy fasciolosis which sometimes arise in acute form take place?

Primary biotopes

A

In places called secondary biotopes, may act as the main source of heavy fasciolosis which sometimes arise in acute form.

The secondary biotopes are developed far from the primary biotopes in consequence of human impact (puddles in roads or in pastures) or **formed by animals **(hoof marks in the mud or wallowing sites)

–> Dense populations!

Secondary biotopes where very dense populations can develop

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18
Q

The severity of the diesease (F.hepatica) in relation to nr of snails or individual?

The release of cercaria

A

Even in case of crowding of snails only a very small amount of them gets infection and release cercariae.

But some individuals are enough to emit several thousands of cercariae and cause mass mortality in a flock of sheep.

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19
Q

What is the DEFINITE host of Faciola Hepatica?

A
  • All kinds of ruminants, mainly the hollow-horned ones (bovidae)
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20
Q

What is the most susceptible DEFINITE host of Faciola Hepatica?

A

*** sheep,
* goat, **
* rabbit,
* hare
* (artificially: mouse, rat )

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21
Q

What is the moderate susceptible DEFINITE host of Faciola Hepatica?

A
  • cattle,
  • deer,
  • roe-deer,
  • moufflon,
  • buffalo,
  • camel,
  • (artificially: guinea pig)
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22
Q

What is the least susceptible DEFINITE host of Faciola Hepatica?

A
  • Horse,
  • pig,
  • dog,
  • cat,
  • humans
  • (aberrant hosts where the patency is infrequent)
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23
Q

Effects of Fasciola in definitive host in relation to temperature

A

In temperate areas symptoms usually appear periodically because most of the cercariae emerge from snails mainly in late summer.

In tropical countries all forms of symptoms may occur in all year because snails emit cercariae all the year.

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24
Q

The following characteristic forms of the disease occur in ruminants:
Typical seasonality
Acute, Subacute, Chronic

A
  • **A= Aug.-Oct.
  • SA= Oct.-Dec.
  • C= throughout the year**
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25
Q

The following characteristic forms of the disease occur in ruminants:
Age of most affected animals

Acute, Subacute, Chronic

A
  • A= 5-8 months
  • SA= 8-12 months
  • C= 1-4 years
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26
Q

The following characteristic forms of the disease occur in ruminants:
**Number of ingested metacercariae **

Acute, Subacute, Chronic

A
  • A= > 2000 metacercariae
  • SA= 500-1500
  • C= 200-500
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27
Q

Appearance of symptoms after

A
  • 2-6 weeks
  • 6-10 weeks
  • 4-5 months
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28
Q

Weight loss

A
  • rapid
  • rapid
  • progressive
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29
Q

Color of sclera and mucosa of mouth

A
  • normal
  • pale
  • pale
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30
Q

Duration of symptoms

A
  • days
  • weeks
  • months
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31
Q

Presence of anemia

A
  • no
  • yes (hemorrhagic)
  • yes/no (blood feeding)
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32
Q

Presence of hypoalbuminemia

A
  • yes
  • yes (edema)
  • yes/no (edema)
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33
Q

Presence of eosinophilia

A
  • yes
  • yes
  • yes/no
34
Q

Presence of ascites

A
  • yes
  • yes
  • yes/no
35
Q

Plasma enzymes in the blood

A
  • GLDH*
  • GLDH, GGT*
  • GGT*

  • GLDH: glutamate dehydrogenase =, indication of parenchymal cell damage
    GGT: gamma-glutamyl transpeptidase, = indication of bile duct epithelial cell damag
36
Q

Changes on the liver

A
  • enlarged organ,
    subcapsular hemorrhagic tracts
  • enlarged organ,
    fibrosis, cholangitis
  • atrophied organ,
    fibrosis, hyperplastic cholangitis
    (in cattle: calcification)
37
Q

Status of abdominal cavity

A
  • peritonitis, exudate
  • peritonitis, exudate
  • peritonitis
38
Q

Number of flukes in the liver of cattle

A
  • > 1000
  • 500-1000
  • 250-500
39
Q

Number of flukes in liver of sheep

A
  • several hundreds
  • > 200
  • > 50-200
40
Q

Location of flukes in liver

A
  • parenchyma
  • parenchyma, bile ducts
  • bile ducts, gall bladder
41
Q

Presence of eggs in feces

A
  • no one
  • eggs
  • eggs
42
Q

Outcome of the infection

A
  • Acute and Subacute = death due to hepatic insufficiency
  • Chronic = Digestive problems
43
Q

Diagnosisin living animals
Symptoms: Acute

A
  • Rapid weight loss,
  • Sudden death
44
Q

Diagnosisin living animals
Symptoms: Subacute:

A

* severe anemia

45
Q

Diagnosisin living animals
chronic:

A
  • submandibular edema,
  • cachexia
46
Q

Diagnosisin living animals
- Praepatent period
- When does eggs appear
- How to detect eggs?

A
  • After 6-12 weeks paepatent period: **presence of eggs in feces **(The egg is 120-150 µm long, oval, dark yellow, thin shelled with a cap [operculum] on one end.
  • Finely granulated yolk around the zygote evenly fills the egg capsule.)
  • Detection of eggs takes place with sedimentation method or flotation with a dense solution.
47
Q

Pathology:
In case of acute disease where do you find the flukes?

A

Young flukes are in the parenchyma

48
Q

Pathology:
In case of chronic form where do you find the flukes?

A

I**n the biliary ducts.

49
Q

Pathology:

What happens after the death of flukes (i.e. consequence of treatment)

A

Fibrotic tracts or necrotic areas remain in liver for lifespan.

50
Q

Paramphistomidosis, which genera occur in EUROPE?

A

Only Paramphistomum and Calicophoron genera occur in Europe, but besides these many other rumen fluke species exist elsewhere.

51
Q

What is Paramphistomid and where does it live?

A

Rumen flukes live in forestomach of many kinds of ruminants.

52
Q

Paramphistomidosis
Morphology

A
  • They are bean-like,
  • 1-2 cm long or smaller,
  • Reddish worms having a smaller sucker on the oral end and another bigger one on the opposite end of the animal.
  • The tough body is filled with genitalia and two branches of intestinal caeci.
53
Q

Paramphistomidosis
Life cycle of Rumen fluke
- Intermediate host
- Migration
- Duration of prepatent period
- Cercaria and Metacercaria

A
  • Similar to the liver flukes’ with some differences:
  • Intermediate host* may be other than lymnaeid snails, and the **juvenile flukes never leave the intestinal canal **during their route from small intestine to the forestomach.
  • The praepatent period after ingestion of parasites is longer than in case of liver flukes: it reaches **16-18 weeks. **
  • Comparison of the life cycle of Fasciola and life cycle of rumen flukes**
  • Cercariae and metacercariae of rumen fluke species have eyespots and are able to develop in several snail species.
54
Q

Intermediate host for Rumen fluke

A
  • In Europe it is mainly **Galba truncatula **for Calicophoron species (!),
  • Coin-shaped, red-blooded pulmonate freshwater snails, the planorbids act as intermediate hosts for Paramphistomum species.
    *** Planorbid snails **live longer than the colorless-blooded lymnaeid snails and are they also **able to survive without water **for rather long period.
55
Q

What is this?

A

Preserved (faded) rumen flukes with the small orifices of the suckers. By their outer shape rumen fluke species can not be distinguished from each other.

56
Q

Which intermediate host is whis, for wich fluke?

A
  • Shells of planorbid snails as intermediate hosts for **Paramphistomum species **
    (Planorbis sp., Segmentina sp. Anisus sp.).
57
Q

Habitat of the intermediate host for the Rumen fluke.
In whick type of animals is it more commonly seen?

A

Wide range of habitats is suitable for intermediate host of rumen fluke species, and that is the reason why this type of infection is more common in wild animals than in livestock.

58
Q

What is the definitive host of the rumen fluke?

A
  • cattle (i.e. for Calicophoron daubneyi),
  • Sheep and goat (i.e. for Paramphistomum cervi),
    * Wild ruminants (i.e. for Paramphistomum cervi, Paramphistomum ichikawai)
    (many other species in tropical countries)
59
Q

Diagnosis in living animals of ACUTE Rumen fluke

A

* Acute form: due to migration of young flukes in the duodenum for 4-6 weeks. (Usually at the end of summer.)
1. profuse diarrhea,
2. anorexia,
3. intense thirst,
4. rectal hemorrhage followed by straining anemia, edema (due to hypoalbuminaemia)
5. emaciation,
6. death (up to 90%)

60
Q

Diagnosis in living animals of CHRONIC Rumen fluke
- Detection of eggs

A
  • Usually asymptomatic because it is well tolerated by hosts
  • After** 3-4 months paepatent period:** **presence of eggs in feces **(The egg is 120-180 µm long, oval, colorless or grayish, thin-shelled with a cap [operculum] on one end.
  • Coarsely** granulated yolk **cells around a zygote evenly fill the egg capsule.)
  • Detection of eggs takes place with sedimentation method or flotation with a dense solution.
61
Q

What is this?

A
  • An **unembryonated egg **of a rumen fluke collected from **fresh feces. **
  • The eccentric zygote is surrounded by coarse yolk granules.
62
Q

here does the rumen fluke attach?

A

A rumen fluke attaches to a papilla among healthy papillae of the rumen.

63
Q

Pathology of the ACUTE rumen fluke
What can be seen?
Where do you find the flukes?

A
  1. Erosions of the duodenal mucosa, in severe cases catarrhal to hemorrhagic enteritis,
  2. **Intestinal wall is edematous **& ulcerated,
  3. Intestinal contents are watery, stinky, rarely ascites.
    * In this period the 2-4 mm long, young flukes are usually embedded in the duodenum therefore they can be found in mucosal scraping.
64
Q

Pathology of the CHRONIC rumen fluke

A
  • Detection of** pinkish worms in rumen** and reticulum is easy.
  • After anthelminthic treatment the scars caused by them can be revealed as small ulcers or shortened rumen papillae.
65
Q

What is Dicrocoeliosis caused by, and what is the common name?
Where do they live?

A
  • Dicrocoelium dendriticum
  • Lives in **hypertrophic biliary ducts **of the liver.
  • This species and its relatives are called lancet flukes.
66
Q

Morphology of the LANCET FLUKE

A
  • Flat,
  • 0.5-1 cm long
  • **Spearhead-shaped **worms.
  • Their transparent body is whitish and the light or dark brown string of eggs shows **trough the tissues. **
  • A small sucker on the tip of the head and another one lay close to it on the ventral side.
  • The** inner part of the body** is filled with large mass of well developed genitals and two branches of intestinal caeci, the later being not functional, therefore they are not visible
67
Q

What is this?

A
  • A fully grown adult Dicrocoelium.
    * 2 larger testicles and
    *** Smaller ovary **are **behind the ventral sucker **
  • Yolk glands are lined up on **both sides **of the worm.
68
Q

What is this?

A
  • The egg of Dicrocoelium with 2 eye-like excretory cells of the miracidium inside.
  • The egg is** hard-shelled** yet is lighter than the egg of** Fasciola** or Paramphistomum.
69
Q

Life cycle of the LANCET FLUKE

A

1. **Adult worms produce small (40-48 µm long) eggs which are shed with feces **and contain **MIRACIDUM.
2. The MIRACIDUM is able to hatch **if the **egg is consumed by a landsnail.
3. Larva hatches** in the** intestine of snail** and develops in the body cavity of the intermediate host to sporocyst.
4.The bladder like sporocyst produces several generations of other sporocysts (so called daughter sporocyst).
5.After some time, inside the sporocyst, CERCARIA develop (omitting the redia stage) by asexual budding, called paedogenesis. Cercariae have very long tails and a sharp spine on the tip of the head, called **stylet.
6.CERCARIA** are NOT able to swarm out of the snail spontaneously but **leave it in the expelled mucus **of snail while the **mollusk crawls on the plants.
7.The CERCARIA remain is in slime balls attached to objects that the snail had visited.
8.Ants ingest the sticky slime** and this way they are infected with the larval lancet fluke.
9.After penetration of the intestine with their stylet the larvae turn to metacercariae in the body of the insect: many of them formed a tick walled cyst in the body cavity but only one of them goes to the side of sub-esophageal ganglion and modify the behavior of the ant. Infected specimens of ant grab the top of the grass and remain motionless from dusk to dawn.
10.Ants are accidentally** ingested by grazing animals** then swallowed and digested. Encapsulated metacercariae of the fluke can get out of their own capsule in the small intestine of final host and turn to juvenile flukes.
9 Emerging juvenile flukes reach the liver through the biliary ducts and develop to adults within them.
- Praepatent period is unknown precisely; it is about 7-9 weeks.

70
Q
A

In temperate zone many small landsnails may act as first intermediate host for lancet flukes.

71
Q

What is the first intermediate host in LANCET FLUKE in temperate zones?

A

In temperate zone many small landsnails may act as first intermediate host for lancet flukes.

72
Q

Intermediate host in LANCET FLUE larvas?
How long does infected snail survive?

A
  • The larva has no host specificity.
    [In Europe mainly the following ones are the hosts:
  • Cepaea vindobonensis,
  • Zebrina detrita,
  • Xerolenta obvia,
  • Monacha cartusiana,
  • Chondrula tridens,
  • Cochlicopa lubrica,
  • Granaria frumentum and
  • Pupilla muscorum
  • Infected snails survive 1-4 years and the occurrence of the parasite in them is not
    seasonal.
73
Q

What is the second intermediate host for the LANCET FLUE?
And how long can they survive?

A
  • Ants in the Formica genus but maybe other ant species can be involved in the life cycle.
  • Infected ants can survive maximum 1 year
74
Q

What is this?

A

Shells of terrestrial snails that can be the common
Intermediate hosts for the lancet fluke.

75
Q

What is this?

A

Group of ants aggregated on the ejected mucus of a snail.

76
Q

What is the definitive host for the LANCET FLUKE?

A
  • Sheep,
  • Goat,
  • Cattle,
  • Wild ruminants,
  • Rabbit,
  • Hare,
  • Rarely pig & horse, (exceptionally humans)
77
Q

How to diagnose LANCET FLUE in living animals?
Acute fluke?
Praepatent period?
Precence of egg?
Detection of eggs?

A

*** Acute form never occurs! **
* Symptoms are generally absent, but in severe cases (with at least ca. 5-10 000 flukes) anemia, edema, weight loss.
* After 7-9 weeks paepatent period: presence of eggs in feces (The egg is 40-48 µm long, asymmetrically oval, dark, brown, thick shelled with an invisible cap [operculum] on one end.
* It contains a MIRACIDUM.
* **Detection of eggs **takes place with flotation with a dense solution or with long lasting sedimentation

78
Q

Pathology of LANCET FLUKE

A
  • The liver is never enlarged, its surface is mottled and on the cut surface we can see the sections of dilated smaller bile ducts with thickened whitish walls**.
  • The parenchyma is intact because of absence of migratory phase. **
  • The larger bile ducts may become markedly distended, but their wall sometimes is not changed or moderately thickened in heavy infection.
  • Adult worms are recognizable by their conspicuous pattern of their inner organs.
79
Q

What is this?

A

Chronic dicrocoeliosis: thick walled bile ducts in the cut surface of a sheep liver.

80
Q

What is this?

A

**Chronic fasciolosis: **adult flukes in the enlarged and opened bile duct of a cattle liver.

Parasitology II (11 decks)

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