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Clinical Parasitology > Nematodes > Flashcards

Nematodes Flashcards

1
Q

Describe Toxocara canis (canine ascarid)

A
  • Live in the SI
  • adults are very large (up to 18 cm)
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2
Q

Describe the life cycle of T. Canis

A
  • Adults found in the SI of the DH
  • non-larvated eggs leave DH via feces
  • eggs larvate in environment
  • Larvated egg is infective to DH
  • possible routes of transmission:
    • Direct transmission (ingestion)
    • prenatal/transuterine
    • colostral/lactogenic
    • ingestion of paratenic host
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3
Q

Direct transmission of T. Canis in dogs <3 months old

A
  • Ingest infective larvated egg
  • tracheal migration
    • Larva hatch from egg in duodenum —> penetrate intestine and migrates to mesenteric l.n. —> migrates to liver — heart — pulm art — lungs
    • molts — alveoli —bronchioles —trachea — coughed up/swallowed —stomach
    • molts to L4/L5 in SI - mature to adult
  • PPP = 3-4 wks
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4
Q

Direct transmission of T. Canis in dogs > 3 months old

A
  • Ingest infected larvated egg
  • Somatic migration
    • ​​​larva hatches from egg in duodenum
    • Penetrates intestine - migration, enters systemic circulation —> returns to heart (does NOT penetrate alveoli)
    • larvae encyst (hypobiotic) in various tissues (liver, lungs, etc)
    • No maturation occurs
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5
Q

Prenatal/transuterine transmission of T. Canis

A
  • Most common way puppies infected
    • ​hypobiotic larvae - mobilize day 42 of pregnancy
    • larvae migrate to fetuses
      • Liver to fetus
      • larvae in lungs at birth — alveoli — bronchioles — trachea —coughed up/swallowed —stomach
      • L4/L5 in SI - mature to adults in approx. 2 weeks
    • Eggs are found in puppy fecesin by 23-40 days old
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6
Q

Colostrum/lactogenic transmission of T. Canis

A
  • Larvae in mammary tissues —> infected during lactation
  • larvae passed to puppies via colostrum
  • go directly to stomach — SI
  • NO migration
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7
Q

Transmission of T. Canis via ingestion of a paratenic host

A
  • Ingest paratenic host with encysted larvae
    • ​rodents, sheep, pigs, earthworms
  • larvae go directly to stomach— SI
  • NO migration
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8
Q

How do the life cycles of T. Cati and T. Leonina differ from that of T. Canis?

A

T. Cati

  • direct transmission - tracheal migration
  • ingest paratenic host - rodents, roaches, earthworms
  • lactogenic transmission - if newly infected
  • PPP = 8 weeks

T. Leonina

  • direct transmission - no migration
  • ingestion of paratenic hosts
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9
Q

Describe the disease caused by ascarids

A
  • More problematic in young puppies/kittens
  • heavy infections: death rare
    • pnemonia (migrations)
    • V/D, obstructions
    • focal CNS lesions
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10
Q

Describe Toxocara cati

A
  • Habitat: SI of cats
  • Adults are smallest of ascarids
  • Eggs: dark center, rough shell, smallest
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11
Q

Describe Toxocaris leonina

A
  • Habitat: SI of cats and dogs
  • Adults larger than T. Cati, smaller than T. Canis
  • Eggs: hyaline center, smooth shell
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12
Q

Which ascarid is which?

A
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13
Q

How do you diagnose Ascarids?

A
  • Eggs in fecal float, adults in feces
  • Usually in puppies
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14
Q

How do you treat Ascarids?

A
  • Dogs and cats: Fenbendazole, milbemycin, moxidectin, pyrantel
  • Cats (T. Cati): selamectin, emodepside
  • Treat nursing dams with litter - every 2 weeks until 12 weeks, then monthly until 6 mo
  • Pregnant bitches: Fenbendazole, ivermectin
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15
Q

How do you control ascarids?

A
  • Remove feces daily - clean, then bleach
  • rodent control
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16
Q

Describe visceral larval migrants (VLM)

A
  • T. Canis
  • Chronic granulomatous lesions due to larval migrations
    • ​often liver, lungs, brain, eye
    • enlarge liver
    • loss of weight, appetite, persistent cough
  • Human is paratenic host
    • ​children - dirt eaters
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17
Q

Describe Baylisascaris procyonis

A
  • Ascarid nematodes
    • large, milky white
    • adults very large: 12-24 cm
    • eggs: feces of DH
      • ellipsoidal, dark brown
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18
Q

Describe the life cycle of B. Procyonis

A
  • DH: raccoons, dogs, kinkajous
  • Direct transmission: larvated eggs
    • ​PPP: 50-76 days
  • Ingestion of paratenic host
    • mice, woodchuck, rabbit, bird, humans
    • PPP: 32-38 days
  • Eggs released by DH
    • up to 2 weeks to larvate in environment
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19
Q

How is B. Procyonis transmitted to humans?

A
  • Ingestion of larvated eggs
    • contaminated food/water
    • hay, straw, bedding
  • geophagy or pica
  • consumption of raw meat
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20
Q

What are the clinical signs of Baylisascaris infections in the DH?

A
  • Usually none in raccoons or dogs
  • heavy infections (raccoons) have been associated with intestinal obstruction
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21
Q

What are the clinical signs of Baylisascaris infections in the paratenic hosts?

A
  • rodents, rabbits, primates, birds = high susceptibility
    • severity varies with species and # of larvae
  • Can be none - low # of larvae that fail to migrate to CNS
  • Resp distress - high # of larvae migrate thru lungs
  • Granulomas -large # of worms migrate thru tissues
  • Invasion of spinal cord or brain - causes hemorrhage, necrosis, inflammation
    • circling, torticollis, paresis, paralysis
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22
Q

What parasite is this?

A

Baylisascaris procyonis

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23
Q

How do you diagnose B. Procyonis in the DH?

A

Eggs in fecal float

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24
Q

How do you treat B. Procyonis?

A
  • Adults (DH)
    • pyrantel, piperazine, Fenbendazole, milbemycin, moxidectin
  • Migrating larvae
    • low level/early CNS infection possible - guarded prognosis
    • albendazole + steroids
  • Decontaminate area
    • heat: boiling water, steam cleaner, flame gun, autoclave, burning straw
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25
Q

How do you manage B. Procyonis?

A
  • Keep food/bedding away from raccoons that could defecate in product
  • do not
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26
Q

Describe Thelazia californensis (eyeworm)

A
  • Habitat: conjunctiva and tear ducts
  • DH: dogs, cats, sheep, humans
  • IH: face fly (Musca autumnalis, Fannia)
  • Morph:
    • Adults 8-18 mm
    • Egg - embryonated, hatch in uterus of female worm
    • Larvae - L1
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27
Q

Describe the life cycle of T. californensis

A
  • First stage larvae (L1- in tears) ingested by face fly
  • Molt to L3 in fly
  • L3 larvae deposited when the fly feeds around the eye
  • Mature to adults in the conjunctiva/lacrimal duct
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28
Q

Describe the disease process caused by T. californensis

A
  • lesions result only from large # of worms
    • ​conjunctivitis, keratitis
    • photophobia
    • excessive tearing
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29
Q

How do you diagnose T. californensis?

A
  • observe parasites on eye surface, conjunctival sac
  • lacrimal secretions may contain L1 larvae
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30
Q

How do you treat T. californensis?

A
  • Remove parasites - manual, brush or irrigation
  • Ivermectin
  • Control Musca autumnalis
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31
Q

Describe Dioctophyme renale (giant kidney worm)

A
  • Habitat: kidney
  • DH: dogs, wolves, foxes, mink (main DH), rarely - cats, humans, pigs, cattle
  • IH: annelid (Lumbriculus sp.) - lives on the surface of crayfish
  • Possible paratenic hosts - fish, frogs
  • Morph:
    • Adults LARGE 14-100 cm long
    • Eggs - barrel shaped, bipolar plugs, rough shell, nonembryonated
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32
Q

Describe the life cycle of of D. renale

A
  • Eggs leave DH via urine – viable up to 5yrs in environment
  • ingested by annelid (IH) - develop to L3
  • paratenic host may ingest annelid/crayfish - L3 encyst
  • DH ingests annelid/crayfish or paratenic host
  • L3 excysts – leaves intestine, migrates to kidney - matures
  • PPP = 5 mo - 2 yr
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33
Q

Describe the clinical signs and disease process caused by D. renale?

A
  • usualy right kidney only: no clinical signs
  • Adults: block ureter, peritonitis, renal failure
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34
Q

What is this parasite?

A

Dioctophyme renale

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35
Q

How do you diagnose and treat D. renale?

A

Dx: urine, adults

Tx: none, remove adults, kidney?

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36
Q

Describe Pearsonema plica (P. feliscati) - urinary bladder worm

*aka Capillaria plica/feliscati

A
  • Habitat: urinary bladder, renal pelvis
  • DH:
    • Cats: P. feliscati
    • Dogs, wolves, foxes: P. plica
  • Paratenic host: earthworm
  • Morph:
    • Adults: 13-60 mm
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37
Q

Describe the life cycle of P. plica/feliscati

A
  • Eggs leave DH via urine - larvate to L1
  • Egg w/ L1 ingested by earthworm (IH) - L1 in tissues
  • DH ingests earthworm - larvae released in intestine
  • L1 excysts - penetrates intestine, matures in mucosa of urinary bladder
  • PPP = 2 mo
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38
Q

What are the clinical signs of the disease caused by Pearsonema spp.?

A
  • mostly asymptomatic
  • irritation of bladder mucosa, cystitis
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39
Q

How do you diagnose and treat Pearsonema spp.?

A

Dx: urine

Tx: none approved, fenbendazole, ivermectin, may need to repeat

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40
Q

Describe Eucoleus aerophilus (E. boehmi) - lungworms

A
  • Habitat:
    • E. aerophilus - resp tract of dogs, cats, foxes
    • E. boehmi - nasal cavity, paranasal sinuses of dogs, foxes
  • Direct life cycles
  • Morph:
    • Adults: 1.5-4 cm
    • Eggs:
      • E. aerophilus - netted
      • E. boehmi - pitted
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41
Q

Describe the life cycle of Eucoleus spp.

A
  • Adults in lungs, eggs leave DH via feces
  • Eggs larvate
  • DH ingests larvated egg - larvae released in intestine, penetrate mucosa
  • Larvae migrate to lungs – mature in bronchioles, bronchi, and trachea
  • PPP: 40d
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42
Q

What is this parasite?

A

Eucoleus aerophilus

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43
Q

Describe the clinical signs and the disease process caused by Eucoleus spp.

A
  • usually asymptomatic
  • severe infections: coughing, nasal d/c, bronchitis, pneumonia, anorexia, dyspnea
    • 2ndary bacterial infections possible
  • mucosal edema, inflammation, hemorrhage
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44
Q

How do you diagnose and treat Eucoleus spp.?

A

Dx: fecal exam, differentiate from similar eggs

Tx: experimental

  • E. aerophilus (cats) - imidacloprid, moxidectin
  • E. boehmi (dogs) - milbemycin, imidacloprid, moxidectin
  • Ivermectin or fenbendazole
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45
Q

Describe Spirocerca lupi (esophageal worm)

A
  • Habitat: caudal esophagus
  • DH: dogs, foxes, wild and domestic felids
  • IH: dung beetle
  • Possible paratenic hosts: amphibians, reptiles, birds
  • Distribution: worldwide, mainly tropical/subtropical regions
  • Morph:
    • Adults: coiled, bright red (30-88 mm)
    • Eggs: larvated, thick shell
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46
Q

Describe the life cycle of S. lupi

A
  • Larvated eggs found in the lumen of esophagus, make their way to intestine – out via feces
  • Eggs ingested by dung beetle (IH) - develops to L3
  • Paratenic host may or may not be utilized - L3 encysts
  • IH or paratenic host ingested by DH - L3 migrates from stomach - gastric arteries - aorta
  • Remain in aorta for >2mo - migrate to esophagus – nodule formation/mature/mate
  • PPP = 5-6 mo
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47
Q

Describe the clinical signs of the disease process caused by S. lupi

A
  • Larval migration: hemorrhage, inflammatory reactions, necrosis
    • roughened aorta, aneurysms, death
  • Adults: nodule formation (1-4 cm) - obstruction of esophagus, vomiting, emaciation +/- mild anemia
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48
Q

What parasite causes this lesion?

A

Spirocerca lupi

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49
Q

What parasite caused this lesion?

A

Spirocerca lupi

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50
Q

How do you diagnose S. lupi?

A
  • Flotation - high specific gravity
  • Endoscopy (most sensitive)
  • Radiography - esophageal mass, undulant border of aortic wall, spondylitis
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51
Q

How do you treat S. lupi?

A
  • ivermectin +/- oral prednisolone
  • doramectin
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52
Q

How do you control S. lupi?

A
  • prevent hunting or scavenging (ingesting paratenic host)
  • prompt removal of feces
  • controlling coprophagous beetles usually not feasible
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53
Q

Describe Physaloptera praeputialis (P. rara) - the stomach worm

A
  • DH:
    • P. praeputialis - cats
    • P. rara - dogs
  • IH: coprophagous beetles, roaches, grasshoppers
  • Possible paratenic host: snake, rat, frog
  • Morph:
    • Adults 14-48 mm
    • Eggs: small, oval, smooth, thick shell, larvated
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54
Q

Describe the life cycle of Physaloptera spp.

A
  • Larvated eggs pass out of DH - via feces
  • Eggs ingested by beetle, cockroach, grasshopper (IH) - develops to L3
  • Paratenic host may or may not be utilized - snake, rat, frog; L3 encyst
  • IH or paratenic host ingested by DH - L3 released into stomach - attach to mucosa, mature
  • PPP = 5-6 mo
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55
Q

Describe the clinical signs and disease caused by Physaloptera spp.

A
  • usually asymptomatic
  • Adults: edematous wounds in stomach - continue to bleed, chronic vomiting, eroded/inflamed mucosa
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56
Q

How do you diagnose Physaloptera spp.?

A
  • fecal or vomitus exam - high specific gravity
  • dark, tarry feces
  • adults in vomitus
  • endoscopy
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57
Q

How do you treat Physaloptera spp.?

A
  • mebendazole
  • pyrantel pamoate
  • fenbendazole
  • ivermectin
58
Q

Describe Ollulanus tricuspis (stomach worm of cats)

A
  • Habitat: Stomach of cats, foxes, pigs, rarely dogs
  • Direct lifecycle
  • Morph:
    • Adults - very small 0.7-1 mm; 5 cusps at posterior end
    • Eggs hatch in female, L3 released
59
Q

Describe the lifecycle of O. tricuspis

A
  • L3 in lumen of stomach (adults burrow into mucosa)
  • Enter environment as L3 via parasite-induced vomitus
    • some mature to adults in the same host
    • ​L3 lives in vomitus up to 12d
  • DH ingests L3, mature to adults in stomach
  • PPP = 33-37 d
60
Q

Describe the clinical signs and disease process caused by Ollulanis tricuspis

A
  • Clinical signs: vomiting, chronic gastritis, wt loss, anorexia
61
Q

How do you diagnose O. tricuspis?

A
  • L3, L4 or adults in vomitus
  • Baermann
  • stomach irrigation
62
Q

How do you treat O. tricuspis?

A

fenbendazole, oxfendzole, tetramisole

63
Q

Describe Strongyloides stercoralis (S. tumefaciens) - threadworm

A
  • Habitat: SI
  • DH:
    • S. stercoralis - dogs, primates, humans
    • S. tumefaciens - cats
  • Morph:
    • Parathanogenic females 3N (parasitic)
    • Free living males and females
      • small thick rhabditiform esophagus
    • Eggs (S. tumefaciens): ellipsoidal, thick shelled, embyronated
    • L1 larvae - S. stercoralis
64
Q

True or false: the lifecycle of Strongyloides spp. is dependent on environmental conditions

A

True

  • Homogenic: parthenogenesis - unfavorable conditions
  • Heterogenic: sexual - satisfactory conditions
65
Q

Describe the life cycle of Strongyloides spp.

A
  • Embryonated eggs are passed in feces - develop into L1 OR L1 passed in feces (S. stercoralis)
  • If unfavorable conditions
    • Homogonic cycle - 3N females survive - larvae develop to L3
  • If favorable conditions
    • Heterogonic cycle - free living males/females; eggs hatch - develop in L3
  • Infective 3N larvae (L3) infect vertebrate host - penetrate skin or ingested (ingestion via milk or colostrum)
  • migration to lungs - trachea- descend to esophagus - intestine
  • mature (L4 or L5) to adult parthenogenic females (3N)
66
Q

What are the clinical signs of the disease caused by Strongyloides spp.?

A
  • usually asymptomatic
  • young animal/large # worms: erosion of intestinal mucosa, diarrhea, weight loss, inappetence
  • autoinfections: young, immunosuppressed animals - verminous pneumonia (lung migration)
67
Q

How do you diagnose and treat Strongyloides spp.?

A

Dx: fecal exam

  • eggs (S. tumefaciens)
  • larvae (S. stercoralis, S. tumefaciens)

Tx: ivermectin, fenbendazole

68
Q

Describe Ancylostoma caninum - canine hookworm

A
  • Habitat: SI of dogs
  • Morph:
    • Adults: medium sized nematodes, may be red
    • 3 pairs of teeth
69
Q

Describe Ancylostoma tubaeformae

A
  • Habitat: SI of cats
  • 3 pairs of teeth
70
Q

Describe Ancylostoma braziliense

A
  • Habitat: SI of dogs and cats
  • 2 pairs of teeth
71
Q

Describe Uncinaria stenocephala

A
  • Habitat: SI of dogs
  • Morph: large buccal cavity, cutting plates
  • Distribution: Northern N. America
72
Q

Describe the life cycle of A. caninum

A
  • Adults in SI - attached to mucosa
  • Non-larvated eggs leave DH via feces
  • Eggs larvate in environment - good moisture/temps (moist sandy soil)
  • In 24 hrs L1 develops in egg - hatches
  • Molts to L2 - matures to L3 but does not molt, remains ensheathed - now infective
  • Now infects DH - 1 of 5 possible ways
73
Q

What are the 5 ways A. caninum infects the DH?

A
  1. Oral - ingestion of L3
  2. Skin penetration by L3
  3. Prenatal/transplacental infection
  4. Lactogenic infection
  5. Ingestion of paratenic host
74
Q

Describe oral infection of the DH by A. caninum

A
  • ingestion of L3 larvae
  • rare; not usually found in nature
  • no larval migration; adults mature in SI
  • PPP = 15-18d
75
Q

Describe skin penetration of the DH by A. caninum in dogs < 3 months old

A
  • ​L3s penetrate skin (paw pads, oral MM)
  • Extensive migration
    • reach blood or lymphatic vessels
    • carried to heart - lungs
    • pass into alveoli - migrate up bronchioles - bronchi - swallowed
    • mature to adults in SI
76
Q

Describe skin penetration of the DH by A. caninum in dogs > 3 months old

A
  • L3s penetrate skin (paw pads, oral MM)
  • Extensive migration
    • reach blood/lymphatic vessels
    • follow more ‘somatic route’
    • become dormant (hypobiotic) - encyst in mm. - repopulate SI when existing adults eliminated
77
Q

Describe prenatal/transplacental transmission by A. caninum

A
  • Rare
  • L3s enter blood stream, pass to placenta - enter fetus
    • most likely hypobiotic larvae or if pregnant bitch becomes infected during pregnancy
78
Q

Describe lactogenic transmission by A. caninum

A
  • L3s recovered from milk u_p to 20d after whelping_
  • hypobiotic larvae migrate to mammary glands
  • adults mature in SI; no migration
79
Q

Describe paratenic host transmission by A. caninum

A
  • ingest host that harbors encysted hypobiotic L3s
    • mice and rats common
  • adults mature in SI; no migration
80
Q

Describe the differences in the life cycles for A. tubaeformae, A. braziliense, and Uncinaria stenocephala from A. caninum

A
  • A. tubaeformae: only acquired after birth via environmental contamination
    • no lactogenic infections
    • PPP: 18-28d
  • A. brazilense
    • PPP: 13-27d
  • U. stenocephala
    • oral infection most successful
81
Q

Describe the clinical signs caused by Ancylostoma spp

A
  • diarrhea w/ blood (mucus, black or tarry)
  • poor appetite
  • poor growth/hair coat
  • weak
  • pale MM
  • hemorrhagic pneumonitis - migrating larvae
  • moist eczema
82
Q

Describe the disease process caused by A. caninum

A
  • Anemia - puppies hardest hit
  • A. caninum and A. tubaeformae = MOST pathogenic
83
Q

Describe Peracute Hookworm Disease

A
  • transmammary infection (50-100 adults) may kill the puppy
  • puppy health deteriorates 2wks PI
    • pale MM, dark liquid feces
    • transfusion often needed to keep puppy alive
  • treat bitches w/ fenbendazole
84
Q

Describe Acute Hookworm Disease

A
  • Sudden exposure of older pups
    • large # of larvae
    • High FEC
    • clinical signs before eggs
    • treatment is effective, nutritional support
85
Q

Describe Chronic Hookworm Disease

A
  • Without clinical signs
    • ​eggs in feces
    • reduced RBC count or PCV
    • often just ‘poor doer’
86
Q

Describe Secondary Hookworm Disease

A
  • Older dogs
    • hookworms = not main culprit
    • anemic, malnourished, emaciated
    • if not responsive to tx, supportive therapy
87
Q

How do diagnose Ancylostoma?

A

eggs in fecal float

88
Q

How do you treat Ancylostoma?

A
  • Adults
    • A. caninum: fenbendazole, milbemycin, moxidectin, pyrantel
    • A. braziliense: pyrantel
    • U. stenocephala: pyrantel, fenbendazole, moxidectin
    • A. tubaeformae: emodepside, ivermectin, milbemycin, moxidecitn, pyrantel, selamectin
  • L4 - intestine
    • A. caninum, U. stenocephala: moxidectin
    • A. tubaeformae: emodepside, moxidectin
89
Q

How do you control Ancylostoma infections?

A
  • difficult due to hypobiosis
  • keep kennels dry and clean
  • pick up feces daily!
90
Q

Describe the zoonotic risk of Ancylostoma infections

A
  • Cutaneous Larval Migrans (CLM)
    • Ancylostoma braziliense
    • L3s penetrate skin
  • rarely enter SI and mature to adults
91
Q

Describe Trichuris Vulpis (T. campanula, T. serrata)

A
  • Habitat: mainly cecum, larvae in mucosa of SI
  • Hosts:
    • T. vulpis - dogs
    • T. campanula, serrata - cats
  • Dist: worldwide
  • Morph:
    • Adults - whiplike
92
Q

Describe the lifecycle of Trichuris spp.

A
  • Females produce nonembryonated eggs - passed in feces
  • eggs larvate (9-21d - temp/soil conditions) - viable for years
  • larvated eggs are ingested
  • larvae enter the wall of the SI and LI, develop to L4
  • larvae return to the lumen migrate to the cecum - mature to adults
  • PPP = 74-90d
93
Q

Describe the clinical signs and disease process caused by Trichuris spp.

A
  • most infections are asymptomatic
  • adults: blood feeders - disease depends on age of host, # of worms present
    • anemia
    • bloody, mucoid diarrhea
    • wt loss
    • dehydration
    • death
94
Q

How do you diagnose Trichuris spp. infections?

A
  • fecal exam - high spec grav
  • long prepatent period - may show C/S prior to eggs in feces
  • eggs shed intermittently
95
Q

How do you treat Trichuris infections?

A
  • Drontal Plus (febental, pyrantel, praziquantel)
  • fenbendazole
  • HW preventatives also approved for whips: Interceptor (Plus), Sentinel (Spectrum), Advantage Multi, Trifexis
96
Q

Describe Filaroides hirthi/F. Osleri (lungworm/tracheal/bronchial nodular worm)

A
  • DH: dogs and coyotes
  • Habitat:
    • F. Hirthi - lung parenchyma
    • F. Osleri - nodules at bifurcation of trachea
  • Direct lifecycle
  • Distribution: F. Osleri - western, midwestern US, Canada
  • Morph:
    • Adults: filamentous
    • larvae (L1): “kinky” tail, lacks dorsal spain
97
Q

Describe the Filaroides lifecycle

A
  • L1 larvae leave DH via feces, sputum, resp secretions
  • New DH ingests L1
  • Migrate to lungs via lymphatics or venous system
  • Key points:
    • ​Larva are infective when passed
    • Direct lifecycle so spreads quickly in kennels
    • Moms can pass to pups from grooming or regurging food (F. Osleri mostly)
  • PPP:
    • F. Hirthi - 5 weeks
    • F. Osleri - -7 mo
98
Q

What parasite is this?

A

Filaroides osleri - tracheal nodules

99
Q

How do you diagnose Filaroides spp.?

A
  • Fecal exam, sputum
  • Baermann or float?
  • radiography
  • endoscopy

*often misdiagnosed as kennel cough

100
Q

How do you treat Filaroides spp.?

A
  • F. Osleri
    • fenbendazole, ivermectin, doramectin, oxfendazole, thiabendazole, remove nodules
  • F. Hirthi
    • albendazole, Fenbendazole, ivermectin
101
Q

Describe Aelurostrongylus abstrusus (feline lungworm)

A
  • Habitat: lung parenchyma of cats
  • possible paratenic hosts: rodents, birds, amphibians, reptiles
  • Most important route of infection = predation
  • Morph:
    • Adult - filamentous
    • eggs “hatch” in lungs - L1 has kinky tail w/ dorsal spine
102
Q

Describe the life cycle of A. Abstrusus

A
  • Eggs in nests in lung nodules - L1 hatch and leave DH via feces
  • L1 ingested by land snail (IH) - develop into L3
  • Paratenic host may ingest snail or slug - L3 encysts
  • DH ingests snail/slug or paratenic host
  • L3 excyst - leaves intestine, migrates to lungs - matures
  • PPP: 4-6 wks
103
Q

Describe the clinical signs and disease process caused by A. Abstrusus

A
  • Light infections: asymptomatic
  • Mod infections: coughing, anorexia
  • Heavy infections: chronic cough, dyspnea, diarrhea, wasting
    • L1s generate strong inflamm response —> damage alveoli/bronchioles/pulm art
  • Nodules on lung surface - milk fluid, eggs, larvae
104
Q

Which egg belongs to which parasite?

A
  • Top left - Trichuris (smooth shell, symmetrical plugs, polar rings, brown)
  • Top right - Pearsonemia (asymmetrical plugs, light yellow)
  • Eucoleus eggs are almost clear
105
Q

How do you diagnose and treat A. Abstrusus?

A

Dx: fecal exam - L1s, thoracic rads

Tx: Fenbendazole +/- prednisolone, moxidectin + imidacloprid, ivermectin?

106
Q

Describe Angiostrongylus Cantonensis (rat lungworm)

A
  • DH: rats - heart/pulm art
  • IH: snails/slugs
  • Incidental hosts: humans, non-human primates, opossums, horses, dogs, birds
  • Paratenic hosts: crabs, shrimp, fish, frogs
  • Distribution: Asia, Pacific Islands, Caribbean, Hawaii, Louisiana, FL
  • Morph:
    • L1 - notch in tail
    • L3 - ensheathed
107
Q

Describe the life cycle of A. Cantonensis

A
  • Eggs in lungs, hatch - L1 break thru resp tract, migrate up trachea - swallowed, shed in feces
  • L1 ingested by land snail (IH) - develop into infective L3
    • ​paratenic host may ingest snail/slug
    • Incidental host may ingest snail/slug or paratenic host
  • Rat DH ingests snail/slug or paratenic host
  • L3 migrate to brain - mature to L4/L5
  • L5 (YA) migrate to heart/pulm art - sexually mature adults
108
Q

Describe canine neural angiostrongylosis

A
  • Progressive neuro signs - paralysis, headache (humans)
  • history of eating IH
  • eosinophyllic pleocytosis in CSF
109
Q

How do you diagnose and treat A. Cantonensis?

A

Dx: CSF ELISA? PCR? , necropsy

Tx: supportive care

110
Q

Describe Dracunculus insignis (guinea worm of dogs - serpent on the stick)

A
  • Habitat: subcutaneous tissues
  • DH: dogs, foxes, cats, raccoons, mink
  • IH: copepod (Cyclops spp.)
  • Paratenic host: frog
111
Q

Describe the life cycle of D. Insignis

A
  • female in SQ blister - releases L1s when contacts water
  • IH - copepod ingests L1 - develops into L3
  • Possible paratenic host - frog
  • DH ingests copepod or frog
  • L3 penetrate intestine - migrate to SQ CT
  • Gravid females in skin blister 10-14 mo PI
112
Q

What are the clinical signs of a D. Insignis infection?

A

Painful skin ulcers

113
Q

How do you diagnose and treat D. Insignis?

A

Dx: observe female under skin, coax L1 from blister via water

Tx: Fenbendazole, ivermectin

*best if treated w/in 90d PI

114
Q

Describe Dirofilaria immitis (canine heart worm)

A
  • Habitat:
    • Adult - Right ventricle, pulm art in dogs, cats, ferrets, sea lions, seals
    • Microfilariae - blood stream
  • Morph:
    • Adult - long, slender, white, 5-12 in
    • Mff - tapered at anterior end, tail may be straight or hooked
  • Vector/IH: mosquitoes

***Must differentiate from Acathocheilonema reconditum

115
Q

How do you differentiate D. Immitis from A. Reconditum?

116
Q

Describe occult D. Immitis infections

A
  • Dog harbors male and/or female adults
    • ”hidden” infection
    • possibly d/t single sex infection, low numbers
  • Mff not detectable in peripheral blood
  • best diagnosed with Ag test
117
Q

Describe microfilarial periodicity

A

Variation in numbers of Mff that appear in circulation over time

  • D. Immitis demonstrates:
    • Nocturnal periodicity - Mff are present in blood during evening hours
    • Incomplete periodicity - Mff never disappear completely from peripheral blood during 24hr period
118
Q

What are the stages of D. Immitis?

119
Q

Describe the life cycle of D. Immitis

120
Q

Heart worms are not detectable consistently using most test procedures until they are _____ months old

121
Q

How many mosquito vectors exist for D. Immitis?

A
  • L3 in at least 70 species
  • 23 species can transmit heartworm
  • 14 species are common vectors
122
Q

Describe the clinical signs caused by heart worm disease

A
  • Primarily due to adults in right ventricle, pulm art
  • irritate vessel walls, produce pro-inflamm molecules that induce inflammation of vessels - villous endarteritis
  • Vascular resistance - inflamm incr cardiac workload —> RV hypertrophy
  • Decr cardiac output - decr organ perfusion w/ blood
    • lungs - exercise intolerance
    • liver, kidney dz
  • coughing, hemoptysis
  • vena cava syndrome - overrun w/ worms, infect atrium and vena cava
123
Q

How do you diagnose heart worms?

A
  • Detection of antigen
  • detection of circulating Mff
  • imaging
124
Q

When do dogs become Ag-positive vs. Mff-positive?

A
  • Ag-positive: 5-7 mo (unless on macrocylic lactones and miss doses)
  • Mff-positive: 6.5 mo
125
Q

True or false: Pets receiving macrocyclic lactones may never develop Mff or they may appear only transiently in small numbers

126
Q

When should antigen testing be performed for D. Immitis?

A
  • ANNUALLY
  • Pets not yet receiving preventative medication
    • dogs over 7 months of age AND
    • 6-12 months after starting prophylaxis
  • Dogs missing doses of prevention for more than 3 months (6-12 months after restart)
127
Q

When should you retest for the D. Immitis antigen?

A
  • ANNUALLY
  • when pets with signs consistent with HWD test negative
  • pets in low endemic areas or on prevention have weakly positive results
  • product switch (4.5 and 9 months after switch)

b/c of the sensitivity/specificity of HW Ag tests, accept rather than doubt test results

128
Q

What are some reasons you might have a positive Ag test result and negative Mff result?

A
  1. Maturing infection; Mff not yet in circulation
  2. Use of prevention w/o removing adult worms
  3. Use of microfilaricide w/o removing adult worms
  4. Unisex (female) infection
  5. Dog is a true immune-mediated occult
  6. Failure to use Mff concentration test
129
Q

What are some reasons you might have a negative Ag test result and positive Mff result?

A
  1. Mff are those of another species
  2. Mff were acquired transplacentally
  3. Adult worms were removed/died but Mff persist
  4. Contamination of test materials
130
Q

What are some reasons you might have a variable Ag test result and negative/positive Mff result?

A
  1. Fluctuating antigen level due to number of female worms, age of worms, or quality of sample
131
Q

What is Wolbachia?

A
  • Wolbachia pipientis - Gram negative bacteria
  • endosymbiont of filarial worms
  • Present in all life stages of D. Immitis
  • Necessary for worm survival
  • Contributes to pulmonary and renal inflammation (surface protein)
132
Q

How do you treat heart worms?

133
Q

When is the susceptibility gap for treating D. Immitis?

A

Days 30-100 - not susceptible to either treatment

134
Q

What are some alternatives to immiticide/Diroban?

A
  • Continuous monthly use of preventives
    • currently macrocyclic lactones are not approved for this used
    • requires compliant monthly treatment
    • may require long periods to remove all worms
  • an alternative ONLY when immiticide cannot be used
  • can contribute to resistance
135
Q

How do you treat Mff?

A
  • Moxidectin
  • Ivermectin
  • Milbemycin
  • Selamectin
136
Q

Why might you omit Mff treatment?

A

With really high Mff counts - uses ivermectin, milbemycin at low doses

137
Q

Describe Heartworm-Associated Respiratory Disease (HARD)

A
  • vascular and airway dz caused by the early death of immature heartworms in cats
  • STAGE 1: immature adults in pulm art - inflamm response; immune function suppressed - cats tolerate worms
  • STAGE 2: worms dying​- pulmonary inflammation, thromboembolism
    • can be transient
138
Q

How do you diagnose feline heart worm disease?

A
  • Very difficult
    • <20% microfilaremic
    • nonspecific/transient eosinophilia
    • Ab test - 15-25% false negatives
    • Ag test - cats mostly male HW infections w/ low number of worms
    • radiographs
    • echocardiography
139
Q

What is the prognosis for feline heartworm disease?

A
  • _>_80% survive infections
140
Q

Compare and contrast feline and canine heartworm disease

141
Q

What do each of these spots show results for on a 4DX?

Clinical Parasitology (7 decks)

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