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Module 18: Ruminant Production > Trematodes & Cestodes of Ruminants > Flashcards

Trematodes & Cestodes of Ruminants Flashcards

1
Q

what are the taxonomy of helminths

A

nemathelminthes (roundworms)

  • class nematoda

platyhelminthes (flatworms)

  • class trematoda (fluke)
  • class cestoda (tapeworms)
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2
Q

what are trematodes of ruminants

A
  1. liver fluke
  • fasciola hepatica (common liver fluke)
  • dicrocoelium dendriticum (lancet/tea leaf fluke)
  1. rumen fluke
    * calicophoron daubneyi
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3
Q

what is the lifecycle of Fasciola hepatica

A

Eggs passed in feces and hatch as and develops into motile miracidium which infects the mud snail and undergoes clonal reproduction

Mobile cercaria hatch out of the snail and encyst as metacercariae which can survive on grass for several months which are eaten by the ruminan

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4
Q

how do eggs develop into miracidium in Fasciola hepatica

A

Fluke eggs passed in feces —> 10-25ºC —> embryo nation >2 weeks, temperature dependent

Hatching: moisture, no dung —> miracidium emerges from egg

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5
Q

what is the IMH of fasciola hepatica

A

galba truncatula

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6
Q

how does fasciola hepatica develop in the snail

A

Miracidium burrows into the snail and undergoes clonal reproduction for about > 6 weeks and forms a Cercarium

Cercarium needs about 10-25ºC where they lose their tail and encyst on vertical surfaces (vegetation) and become non motile metacercariae

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7
Q

how does excystation occur in fasciola hepatica

A

CO2 & temperature of ~39ºC

Pepsin in abomasum; trypsin in the duodenum

Glycocholic acid in the bile

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8
Q

how does pregrination occur in Fasciola hepatica

A

Pass through the gut wall and enter the abdominal cavity

Travel along inner surface of abdominal wall

Reach diaphragm, against which lies the ventral lobe of the liver

Juvenile fluke penetrate the diaphragmatic surface of the liver capsule

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9
Q

what occurs from week ~1 to ~8 in parenchyma that causes acute fasciolosis in sheep

A

High numbers (>1000) of migratory juveniles

Parenchyma damage

Hemorrhage within liver tissue

Damage to larger blood vessels can cause catastrophic intra-abdominal hemorrhage

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10
Q

does acute fascioosis occur in cattle

A

very rare

Limited effects on performance in cattle are within first 8 weeks of infection

Major effects associated with bile duct colonization

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11
Q

what occurs in week 8 to 12 in the bile ducts of fasciola hepatica

A

Pre-patent period: 12 weeks

1 fluke can lay 25,000 eggs/day

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12
Q

what does chronic fasciolosis in sheep look like

A

cachexia

anemia

depression

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13
Q

what is the gross pathology of fasciola hepatica in cattle

A

enlarged bile ducts

enlarged gall bladder

fibrosis

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14
Q

does fasciola hepatica affect calf performance

A

Don’t start to see a decrease in performance until around week 8 when they start blood feeding in the bile ducts and they start to loose weight

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15
Q

what does fasciolosis cause in high yielding dairy herds

A

High levels of exposure associated with 15% lower milk yield

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16
Q

what is the pathophysiology of liver fluke

A

Feeding of flukes:

  • Hemorrhage/anemia

Anorexia:

  • Reduced food intake

Liver damage and dysfunction

  • Diverse effects

Immunomodulation:Bacterial co-infection

  • Clostridium novyi
  • Salmonella dublin
  • Mycobacterium bovis

TB diagnostics

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17
Q

what are the infection patterns of fasciola hepatica

A

fection patterns:

Untreated stock carrying infection over winter and pass eggs out in the summer

These eggs will develop and infect during the summer —> rapid increase in infective metacercariae due to high temperatures which leads to a peak of infective capability in autumn

Snails that are infected can carry infection over the winter and can spread infective metacercariae in the spring

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18
Q

what are the seasonal trends in fluke diagnosis in sheep

A

Tend to see a peak in acute liver fluke in sheep in the autumn and second half of grazing season

Chronic liver fluke will build up throughout the winter and can be diagnosed any time but it is mainly a late winter disease

Rumen fluke is all year round and an increase in late winter

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19
Q

how is fluke diagnosed

A
20
Q

how is Coproantigen used to diagnose fluke

A

ELISA test on feces to look for feeding flukes in bile ducts

Can pick up infection earlier than FWEC

But the sensitivity and specificity is not perfect —> better in sheep than cattle

21
Q

how is Immune response used to diagnose fluke

A

Immune response but not an effective against infection

Presence of antibodies show that the animal has been exposed —> doesn’t show that it is a current infection

Rising plane in antibodies might suggest an increase in exposure

Or naive youngstock that have antibodies —> treatment protocols

22
Q

how can GLDH and GGT be used to diagnose fluke

A

Liver function & damage

GLDH = glutamate dehydrogenase (liver parenchyma)

GGT = gamma glutamyl transferase (bile duct)

23
Q

what are performance indicators of fluke

A

ADG

Milk yield

But can’t use this for a targeted selective treatment approach

Careful with differentials for ill thrift

24
Q

what are control measures of flukes

A

grazing management

snail prevention

flukicides

25
Q

how can flukes be managed by grazing management

A

Avoid grazing high risk pastures

Selective grazing in endemic regions

If farm has both high and low risk grazing

  • Move stock off high risk pastures in August
  • Graze cattle on high risk pastures for 8 weeks then treat (& move?)
26
Q

how can flukicides be used to manage flukes

A

Strategic (pasture contamination)

Therapeutic (animal welfare and performance)

27
Q

what are the flukicide spectrum of activities

A

Triclabendazole:

Effect on all stages

Reduce the risk of acute fluke or treat if it has emerged

Resistance developing

Avoid unnecessary use

28
Q

what is the rationale for therapeutic flukicide treatment

A

Remove adult fake to limit damage to host

29
Q

what is the rationale for strategic flukicide treatment

A

Remove adult fluke at key times to limit pasture contamination with fluke eggs

Mainly beef, difficult in adult dairy except spring calving herds

30
Q

what are housing/winter therapeutic treatments for flukes

A

Therapy (cattle not to be grazed again)

Any effective flukicide at housing

May need to re-treat if high % of juvenile fluke?

Monitor: DLWG (bulk fecal eggs?)

31
Q

what are housing/winter strategic treatments for flukes

A

*Fecal egg count to determine efficacy and/or need for treatment

32
Q

what are strategic treatments for fluke at grazing

A

To limit fluke egg output in grazing stock up to July by removing any egg-laying adult fluke

33
Q

what are obsticles to fluke control (4)

A
  1. no natural immunity
  2. practical limitations on ‘environmental’ control
  3. flukicides
  4. treatment recommendations
34
Q

what are the practical limitations on environmental control of flukes

A

Drainage & fencing impractical and expensive

Snail habitats widespread

Population dynamics and dispersal of snails

Domestic livestock and wildlife reservoirs

35
Q

what flukicide products can be used in dairy cows

A
36
Q

what can be used to treat dicrocoeliosis in sheep

A

albendazole at 15-20 mg/kg

37
Q

how is rumen fluke diagnosed

A

Diagnosed (FEC, abattoir) with increased frequency in UK & Ireland ~5 years

38
Q

what is the intermediate host of rumen fluke

A

Galba truncatula

39
Q

what are annual patterns of fluke diagnosis in cattle

A
40
Q

what is the clinical disease of rumen fluke

A

typically affected animal showing diarrhea

dehydration

poor condition

41
Q

where does rumen fluke cause pathology

A

duodenum

42
Q

how is rumen fluke controlled

A

Epidemiological overlap with liver fluke

Snail habitats

Sheep and cattle

43
Q

how is rumen fluke treated

A

Oxyclozanide (Levafas; Zanil)

12.8-18.7 mg/kg once or twice 3 days apart

44
Q

what are important ruminant cestodes

A
45
Q

what are the indirect life cycle of Moniezia expansa

A

one intermediate host oribatid mites

Module 18: Ruminant Production (25 decks)

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