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PARASITOLOGY - 2 > 4 – Non-GI Nematodes, Cestodes, Trematodes > Flashcards

4 – Non-GI Nematodes, Cestodes, Trematodes Flashcards

1
Q

What are some non-GI nematodes?

A
  • Cattle lungworm (Dictyocaulus viviparous)
  • Large sheep lungworm (Dictyocaulus filaria)
  • Stepahnofilaria stilesi (dermal)
  • Muellerius, Protostrongylus (small lungworms of sheep and goats)
  • Setaria (periotoneal)
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2
Q

Cattle lungworm: Dictyocaulus viviparus, adults

A
  • Adults in major airways
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3
Q

Cattle lungworm: Dictyocaulus viviparus, what do you find in the feces

A
  • Detect larvae (L1)
  • *needs to be FRESH!
  • Will die if fecal sample is FROZEN
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4
Q

Cattle lungworm: Dictyocaulus viviparus, lifecycle

A
  • Adult in airways produce L1 that are coughed up
  • L1 into feces to L2 to L3 (translation period, 5 days in ideal WET conditions)
    o Can be a problem in wet years
  • L3 swallowed then to L4 quickly and to adult (tracheal migration to lungs)
    o L4 may arrest if conditions are not ideal: hypobiosis
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5
Q

Cattle lungworm: Dictyocaulus viviparus, prevalence and disease

A
  • Rare, but important cause of pneumonia in pasteured catlle
  • Can be subclinical
  • If clinically: calves or naïve calves on wet pasture
    o Coughing, dyspnea, sawhorse stance
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6
Q

What is the common name of the clinical disease associated with Dictyocaulus viviparus? What time of year do we see it?

A
  • “husk”
  • LATE SUMMER AND EARLY FALL
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7
Q

Cattle lungworm: Dictyocaulus viviparus, morbidity and mortality

A
  • Can be HIGH
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8
Q

Cattle lungworm: Dictyocaulus viviparus, diagnostic tests

A
  • BAERMANN ON FRESH SAMPLES
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9
Q

Cattle lungworm: Dictyocaulus viviparus, control

A
  • Vaccine used in Europe (irradiate L3)
    o Give to calves before first turn out
  • Anthelmintics (especially ML)
    o Give at midpoint of first grazing season
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10
Q

Dictyocaulus filaria (large lungworm of sheep)

A
  • Similar to D. viviparus
  • Less pathogenic in sheep
  • *ANTERIOR CONE ON FIRST STAGE LARVAE IN FECES (Baermann)
  • Same treatment as cattle
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11
Q

How do you control Dictyocaulus filaria in sheep?

A
  • Unusually to cause disease, but TREAT LAMBS with MLs at midpoint of first grazing season (April to May)
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12
Q

What may trigger an outbreak of Dictyocaulus filaria in sheep?

A
  • More common in wetter years OR if recently moved to a wetter pasture
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13
Q

What are the 2 main protostrongylids (small lungworms) in sheep and goats?

A
  • Muellerius
  • Protostrongylus
  • *related to meningeal worm of deer (pathogenic in llamas and alpacas)
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14
Q

Muellerius and Protostrongylus in sheep and goats, adults

A
  • Live in lung parenchyma and/or small airways
    o Notable lung lesions, but rarely clinical
    o Subclinical: respiratory signs, decreased weight gain
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15
Q

Muellerius and Protostrongylus in sheep and goats, larvae shapes

A
  • Muellerius: dorsal spined larvae
  • Protostrongylus: spike tailed larvae
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16
Q

Muellerius and Protostrongylus in sheep and goats, life cycle

A
  • Adults in lungs produce L1 (coughed up and swallowed)
  • L1 in feces
  • Gastrod (ex. snail)
  • L3 which is ingested
    o Either the L3 with vegetation (from emerging spontaneously from gastropod) or the whole gastropod
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17
Q

Muellerius and Protostrongylus: how do you detect them?

A
  • Baermann
    o Adults live in lung and produce L1 that will be coughed up and swallowed
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18
Q

Stephanofilaria stilesi (dermal nematode in cattle)

A
  • Filaria: vector born
  • Very tiny
  • *Live in cyst like structures at base of hair follicles=alopecia and scaling
    o Midline, udder, face, neck
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19
Q

Stephanofilaria stilesi (dermal nematode in cattle), lifecycle

A
  • L3 develops to adults in the hair follicles and produce microfilariae (L1) in DERMIS
  • IH=horn fly: L1 to L2 to L3
  • L3 in dermis
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20
Q

Stephanofilaria stilesi (dermal nematode in cattle), prevalence

A
  • Present in Western Canada
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21
Q

Stephanofilaria stilesi (dermal nematode in cattle), diagnosis

A
  • Clinical symptoms
  • Microfiliar in skin biopsy
    o Macerated and incubated in saline at 37C for 24hrs
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22
Q

Stephanofilaria stilesi (dermal nematode in cattle), treatment

A
  • ML kill the microfilaria and resolve skin lesions within 2-3 weeks
  • Adults RESIST treatment and survive for years!
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23
Q

Setaria sp. Adult

A
  • Can be VERY LONG
  • *little or NO clinical significance
    o Good to know it exists though
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24
Q

Setaria sp. Life cycle

A
  • Adults live in peritoneal cavity, produce microfilaria (L1) in blood
  • IH=horn fly or mosquitoe (L1 to L2 to L3)
  • L3 deposited into blood stream and go to peritoneal cavity
  • *ex. like Dirofilaria (canine heartworm)
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25
Q

What are some Cestodes of sheep and cattle?

A
  • Moniezia sp
  • Thysanosoma sp.
  • Taenia ovis and T. saginata
26
Q

Moniezia sp. (intestinal cestodes) in cattle and sheep, scolex and segments

A
  • Scolex without rostellum or hooks
    o 4 suckers
  • Segments: wide and not super long
    o 2 reproductive organs: 2 lateral pores
27
Q

Moniezia sp. (intestinal cestode) in cattle and sheep, significance

A
  • No clinical significance
28
Q

How do tape worms feed?

A
  • Through their skin!
29
Q

Thysanosoma spp. (intestinal cestode) in cattle and sheep, scolex and segments

A
  • No rostellum or hooks
    o 4 suckers
  • Segments have fringes
30
Q

Thysanosoma spp. (intestinal cestode) in cattle and sheep, significance

A
  • Can also be found in bile and pancreatic ducts
    o May increase their clinical significance
31
Q

Moniezia and Thysanosoma spp. eggs

A
  • Monezia: square with hexacanth larvae and pyriform apparatus
  • Thysanosoma; EGG PACKET with hexacanth larvae inside
32
Q

Moniezia and Thysanosoma spp. life cycle

A
  • Eggs in feces or tapeworms on backend
  • INDIRECT life cycle
    o Adults in intestines of cattle and sheep (DH)
    o Eggs in feces
    o Ingested by free-living mite with cysticercoids (IH)
    o Mites ingested by cattle and sheep
    *more pathogenic in sheep
33
Q

Taenia ovis (ovine cysticercosis)

A
  • Adults live in intestine of dogs (DH)
  • Eggs in feces are IMMEDIATELY infective in sheep (IH)
  • Become cysticerci in muscle
    o Whole carcass may be condemned
34
Q

How do you diagnosis Taenia ovis?

A
  • No clinical signs with adult stages in dogs or cysticerci in sheep
  • Post-mortem: cysticerci in skeletal muscle and heart lead to carcass condemnation
  • *increasing concern for sheep producers in western Canada
  • *confirm using PCR
35
Q

How do you control Taenia ovis?

A
  • No treatment for sheep
  • Treat dogs with praziquantel at least TWICE a year
  • Prevent dogs from eating infected sheep carcasses
  • Prevent dogs (and coyotes) from pooping on pasture
36
Q

Taenia sagninatta (bovine cysticercosis)

A
  • Most common in beef-eating countries other than Canada
    o Eastern Europe, Russia
  • Rare cause of carcass condemnation in feedlot cattle in Canada
  • *predator prey indirect life cycles
  • *eggs immediately infective and resistant (18 months)
37
Q

Taenia sagninatta (bovine cysticercosis): predator prey indirect life cycle

A
  • Human=DH
  • Cattle=IH
38
Q

Taenia sagninatta (bovine cysticercosis): characteristics

A
  • Scolex: NO hooks
  • Taeniid egg: passed in human poop
  • Gravid segment: Christmas tree appearance
  • Cysticercus: protoscolex (in IH)
39
Q

Taenia sagninatta (bovine cysticercosis): life cycle

A
  • Adults in humans (DH)
  • Gravid segments and eggs in feces
    o Ingested by cow (IH)
  • Cysticerci in cardiac and skeletal muscle
    o Human may ingest
40
Q

Taenia sagninatta (bovine cysticercosis): control and treatment in DH

A
  • Treat carrier people with cestocides
  • Goal: halt environmental contamination with immediately infective eggs
  • Prevent access to IH
  • Cook meat to safe internal temperature
41
Q

Taenia sagninatta (bovine cysticercosis): control and treatment in IH

A
  • No treatment available or suitable
  • Meat inspection
  • Prevent livestock access to human feces
42
Q

Taenia sagninatta (bovine cysticercosis): in Canada

A
  • *reportable disease
    o Even if suspicious
  • CFIA meat hygiene program
  • Collect cysticerci fresh and submit for confirmation
  • CFIA national cysticercosis program
43
Q

What are the CFIA action on detection of bovine cysticercosis?

A
  • Quarantine premises and source farms
  • License remaining animals to slaughter
  • Make recommendations to halt transmission
  • Life quarantine/open feedlot after certain number of animals are negative
  • *compensated for losses
44
Q

What are the liver flukes in cattle and sheep?

A
  • Fasciola hepatica
  • Fascioloides magna
  • Dicrocoelium dendriticum
45
Q

Fasciola hepatica

A
  • MOST IMPORTANT trematode livestock
    o Rare in western Canada
  • Grey-brown leaf shaped fluke primarily in bile ducts
  • Can infect many species: cattle, sheep (goats, deer, horses, pigs)
  • Infection only where there is suitable AQUATIC SNAIL habitat
  • ZOONOTIC
46
Q

Fasciola hepatica: life cycle

A
  • Adults in DH (cattle or sheep)
  • Eggs shed in feces
  • Miracidium which penetrates foot of snail
  • IH (snail): sporocyst to redia (*massive ASEXUAL REPRODUCTION)
  • Cercaria
  • Metacercaria on VEGETATION
    o *long survival
47
Q

Fasciola hepatica pathology

A
  • Often asymptomatic
  • Acute/subacute in sheep
  • Chronic in cattle
  • **in all livestock: migrating flukes can TRIGGER CLOSTRIDIAL DISEASE
    o Anaerobic bacteria in liver (then can cause sudden death!)
48
Q

Fasciola hepatica: acute/subacute fasciolosis in sheep

A
  • Migrating juvenile flukes in liver tissue
  • Anemia, hypoalbuminemia, sudden death
  • Submandibular edema (bottle jaw), ascites, eggs present
  • *important differential diagnostic from Haemonchus contortus (barber pole)
49
Q

Fasciola hepatica: chronic fasciolosis in cattle

A
  • Adult flukes in bile ducts
  • Generally sub-clinical
  • Reduced growth and fertility, progressive loss of condition
  • Post-mortem: chronic cholangitis, calcified bile ducts
    o Pipestem liver due to chronic fasciolosis
50
Q

Fasciola hepatica: eggs

A
  • Often missed! TOO DENSE to float
51
Q

What are other tests for Fasciola hepatica?

A
  • Coproantigen, antibodies in bulk tank milk
  • Bloodwork: anemia hypoalbuminema, eosinophila, elevated liver enzymes
  • Liver pathology on post-mortem: meat inspection
52
Q

Fascioloides magna (giant liver fluke)

A
  • Relatively common in cervids in western Canada
    o Regions where aquatic snail is present
  • Livestock and ungulates are DEAD END HOSTS
  • Sudden death in sheep
  • Control is difficult: wildlife reservoir
  • *no ante mortem diagnostic test
53
Q

Fascioloides magna: livestock as dead end hosts

A
  • Chronic or asymptomatic
  • Flukes walled off in liver parenchyma
  • NO EGGS SHED: no clinical signs, UNLESS flukes activate clostrida spores in liver
    o Bacillary hemoglobinuria (REDWATER DISEASE)
  • *DO NOT ORDER FECAL SEDIMENTATION
  • Diagnosis at packing plant
54
Q

What is the life cycle of Fascioloides magna (giant liver fluke)?

A
  • Adults in DH (cervids)
  • Shed eggs in feces
  • Miracidium penetrates snail foot (sporocyst to redia)
  • Cercariae to metacercaria on vegetation
    o Ingested by cattle or sheep=NON-patent infection (can be fatal in sheep)
    o Ingested by cervid (DH)
55
Q

Fasciola hepatica in sheep

A
  • Normal DH
  • Acute fasciolosis
    o Migration of juvenile flukes ingested in short time span
  • Liver damage and haemorrhage
  • Sudden death, anemia, ascites, dyspnea, abdominal pain occurring 2-6 weeks after infection
56
Q

Fascioloides magna in sheep

A
  • Aberrant DH
  • Nonpatent infections
  • Flukes migrate around the liver and cause SIGNIFICANT tissue damage
  • Aberrant hosts usually DIE within a few months of infection (BEFORE PATENT)
57
Q

How do you control flukes in cattle and sheep?

A
  • Rarely necessary in western Canada
58
Q

How do you prevent flukes in problem herds? (herd level diagnosis)

A
  • Avoid known contaminated pastures
  • Avoid liquid manure as fertilizer from infected herds near water
  • Prevent livestock access to wetlands and cervid access to pasture
  • *stay up to date on clostridial vaccines
59
Q

How do you control F. hepatica in problem herds?

A
  • Treatment of all exposed ruminants on farm
  • SHEEP: *Closantel (Flukiver) or triclabendazole in fall) to kill juvenile flukes:
  • DAIRY: albendazole in early winter to kill adult flukes
  • *vaccination for Clostridial disease (at least every 6 months)
60
Q

Dicrocoelium dendriticum (zombie ant fluke)

A
  • Small fluke that lives in bile ducts
  • Incidental finding in cattle, sheep, deer, rabbits, people
  • *not very pathogenic
  • Introduced to BC and Cypress Hills in Canada
  • TERRESTRIAL CYCLE: ant as second IH
61
Q

What is the lifecycle of Dicrocoelium dendriticum (zombie ant fluke)?

A
  • Adults in DH
  • Eggs shed in feces and ingested by snail and miracidium released
    o First IH: snail
    o Cercariae in snail slime/plegm trail=ant eats it (second IH)
    o Ant (second IH): with metacercariae
    o GOES to their brain and they climb vegetation (not normal=more exposed to be eaten by DH)
62
Q

How do you diagnose Dicrocoelium dendriticum in an animal that is alive?

A
  • Detection of eggs in feces using floatation technique (SG: 1.30-1.45)
    o LOW sensitivity
    o Very different from F. hepatica and F. magna
  • Postmortem examination

PARASITOLOGY - 2 (13 decks)

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