Nematodes Flashcards
1
Q
Describe Toxocara canis (canine ascarid)
A
- Live in the SI
- adults are very large (up to 18 cm)
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
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
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
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
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
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
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
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
10
Q
Describe Toxocara cati
A
- Habitat: SI of cats
- Adults are smallest of ascarids
- Eggs: dark center, rough shell, smallest
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
12
Q
Which ascarid is which?
A
13
Q
How do you diagnose Ascarids?
A
- Eggs in fecal float, adults in feces
- Usually in puppies
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
15
Q
How do you control ascarids?
A
- Remove feces daily - clean, then bleach
- rodent control
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
17
Q
Describe Baylisascaris procyonis
A
- Ascarid nematodes
- large, milky white
- adults very large: 12-24 cm
- eggs: feces of DH
- ellipsoidal, dark brown
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
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
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
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
22
Q
What parasite is this?
A
Baylisascaris procyonis
23
Q
How do you diagnose B. Procyonis in the DH?
A
Eggs in fecal float
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
25
How do you manage B. Procyonis?
* Keep food/bedding away from raccoons that could defecate in product
* do not
26
Describe Thelazia californensis (eyeworm)
* 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
27
Describe the life cycle of T. californensis
* 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
28
Describe the disease process caused by T. californensis
* lesions result **only from large # of worms**
* ****conjunctivitis, keratitis
* photophobia
* excessive tearing
29
How do you diagnose T. californensis?
* **observe parasites on eye surface, conjunctival sac**
* lacrimal secretions may **contain L1 larvae**
30
How do you treat T. californensis?
* Remove parasites - manual, brush or irrigation
* Ivermectin
* Control Musca autumnalis
31
Describe Dioctophyme renale (giant kidney worm)
* 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**
32
Describe the life cycle of of D. renale
* 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
33
Describe the clinical signs and disease process caused by D. renale?
* usualy **right kidney only:** no clinical signs
* Adults: **block ureter, peritonitis, renal failure**
34
What is this parasite?
Dioctophyme renale
35
How do you diagnose and treat D. renale?
Dx: urine, adults
Tx: none, remove adults, kidney?
36
Describe Pearsonema plica (P. feliscati) - urinary bladder worm
\*aka Capillaria plica/feliscati
* Habitat: **urinary bladder, renal pelvis**
* DH:
* Cats: P. feliscati
* Dogs, wolves, foxes: P. plica
* Paratenic host: earthworm
* Morph:
* Adults: 13-60 mm
37
Describe the life cycle of P. plica/feliscati
* 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
38
What are the clinical signs of the disease caused by Pearsonema spp.?
* mostly **asymptomatic**
* **irritation of bladder mucosa, cystitis**
39
How do you diagnose and treat Pearsonema spp.?
Dx: urine
Tx: none approved, fenbendazole, ivermectin, may need to repeat
40
Describe Eucoleus aerophilus (E. boehmi) - lungworms
* 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
41
Describe the life cycle of Eucoleus spp.
* 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
42
What is this parasite?
Eucoleus aerophilus
43
Describe the clinical signs and the disease process caused by Eucoleus spp.
* **usually asymptomatic**
* severe infections: **coughing**, nasal d/c, bronchitis, pneumonia, anorexia, dyspnea
* 2ndary bacterial infections possible
* mucosal edema, inflammation, hemorrhage
44
How do you diagnose and treat Eucoleus spp.?
Dx: fecal exam, differentiate from similar eggs
Tx: experimental
* E. aerophilus (cats) - imidacloprid, moxidectin
* E. boehmi (dogs) - milbemycin, imidacloprid, moxidectin
* Ivermectin or fenbendazole
45
Describe Spirocerca lupi (esophageal worm)
* 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**
46
Describe the life cycle of S. lupi
* 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
47
Describe the clinical signs of the disease process caused by S. lupi
* **Larval migration:** hemorrhage, inflammatory reactions, necrosis
* roughened aorta, aneurysms, death
* **Adults:** nodule formation (1-4 cm) - obstruction of esophagus, vomiting, emaciation +/- mild anemia
48
What parasite causes this lesion?
Spirocerca lupi
49
What parasite caused this lesion?
Spirocerca lupi
50
How do you diagnose S. lupi?
* Flotation - **high specific gravity**
* Endoscopy (most sensitive)
* Radiography - esophageal mass, undulant border of aortic wall, spondylitis
51
How do you treat S. lupi?
* **ivermectin +/- oral prednisolone**
* **doramectin**
52
How do you control S. lupi?
* prevent hunting or scavenging (ingesting paratenic host)
* prompt removal of feces
* _controlling coprophagous beetles usually not feasible_
53
Describe Physaloptera praeputialis (P. rara) - the stomach worm
* 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**
54
Describe the life cycle of Physaloptera spp.
* 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
55
Describe the clinical signs and disease caused by Physaloptera spp.
* usually asymptomatic
* **Adults:** edematous wounds in stomach - continue to bleed, chronic vomiting, eroded/inflamed mucosa
56
How do you diagnose Physaloptera spp.?
* fecal or vomitus exam - high specific gravity
* dark, tarry feces
* adults in vomitus
* endoscopy
57
How do you treat Physaloptera spp.?
* mebendazole
* pyrantel pamoate
* fenbendazole
* ivermectin
58
Describe Ollulanus tricuspis (stomach worm of cats)
* 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
Describe the lifecycle of O. tricuspis
* 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
Describe the clinical signs and disease process caused by Ollulanis tricuspis
* Clinical signs: vomiting, chronic gastritis, wt loss, anorexia
61
How do you diagnose O. tricuspis?
* L3, L4 or adults in vomitus
* Baermann
* stomach irrigation
62
How do you treat O. tricuspis?
fenbendazole, oxfendzole, tetramisole
63
Describe Strongyloides stercoralis (S. tumefaciens) - threadworm
* 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
True or false: the lifecycle of Strongyloides spp. is dependent on environmental conditions
True
* Homogenic: parthenogenesis - unfavorable conditions
* Heterogenic: sexual - satisfactory conditions
65
Describe the life cycle of Strongyloides spp.
* 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
What are the clinical signs of the disease caused by Strongyloides spp.?
* usually asymptomatic
* young animal/large # worms: **erosion of intestinal mucosa, diarrhea, weight loss, inappetence**
* autoinfections: young, immunosuppressed animals - **verminous pneumonia (lung migration)**
67
How do you diagnose and treat Strongyloides spp.?
Dx: fecal exam
* eggs (S. tumefaciens)
* larvae (S. stercoralis, S. tumefaciens)
Tx: ivermectin, fenbendazole
68
Describe Ancylostoma caninum - canine hookworm
* Habitat: SI of **dogs**
* Morph:
* Adults: medium sized nematodes, may be red
* 3 pairs of teeth
69
Describe Ancylostoma tubaeformae
* Habitat: SI of **cats**
* **3 pairs of teeth**
70
Describe Ancylostoma braziliense
* Habitat: SI of **dogs and cats**
* **2 pairs of teeth**
71
Describe Uncinaria stenocephala
* Habitat: SI of **dogs**
* Morph: large buccal cavity, **cutting plates**
* Distribution: Northern N. America
72
Describe the life cycle of A. caninum
* 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
What are the 5 ways A. caninum infects the DH?
1. Oral - ingestion of L3
2. Skin penetration by L3
3. Prenatal/transplacental infection
4. Lactogenic infection
5. Ingestion of paratenic host
74
Describe oral infection of the DH by A. caninum
* ingestion of L3 larvae
* **rare; not usually found in nature**
* _no larval migration_; adults mature in SI
* PPP = 15-18d
75
Describe skin penetration of the DH by A. caninum in dogs **\< 3 months old**
* ****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
Describe skin penetration of the DH by A. caninum in **dogs \> 3 months old**
* 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
Describe prenatal/transplacental transmission by A. caninum
* Rare
* L3s enter blood stream, pass to placenta - enter fetus
* most likely hypobiotic larvae or if pregnant bitch becomes infected during pregnancy
78
Describe lactogenic transmission by A. caninum
* L3s recovered from milk u_p to 20d after whelping_
* hypobiotic larvae migrate to mammary glands
* adults mature in SI; no migration
79
Describe paratenic host transmission by A. caninum
* ingest host that harbors encysted hypobiotic L3s
* mice and rats common
* adults mature in SI; no migration
80
Describe the differences in the life cycles for A. tubaeformae, A. braziliense, and Uncinaria stenocephala from A. caninum
* 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
Describe the clinical signs caused by Ancylostoma spp
* **diarrhea w/ blood (mucus, black or tarry)**
* poor appetite
* poor growth/hair coat
* weak
* **pale MM**
* hemorrhagic pneumonitis - migrating larvae
* moist eczema
82
Describe the disease process caused by A. caninum
* **Anemia** - puppies hardest hit
* **A. caninum and A. tubaeformae** = MOST pathogenic
83
Describe Peracute Hookworm Disease
* 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
Describe Acute Hookworm Disease
* **Sudden exposure of older pups**
* large # of larvae
* High FEC
* clinical signs before eggs
* treatment is effective, nutritional support
85
Describe Chronic Hookworm Disease
* **Without clinical signs**
* ****eggs in feces
* reduced RBC count or PCV
* often just 'poor doer'
86
Describe Secondary Hookworm Disease
* Older dogs
* hookworms **= not main culprit**
* anemic, malnourished, emaciated
* if not responsive to tx, supportive therapy
87
How do diagnose Ancylostoma?
eggs in fecal float
88
How do you treat Ancylostoma?
* 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
How do you control Ancylostoma infections?
* difficult due to **hypobiosis**
* keep kennels dry and clean
* pick up feces daily!
90
Describe the zoonotic risk of Ancylostoma infections
* Cutaneous Larval Migrans (CLM)
* **Ancylostoma braziliense**
* L3s penetrate skin
* rarely enter SI and mature to adults
91
Describe Trichuris Vulpis (T. campanula, T. serrata)
* Habitat: **mainly cecum**, larvae in mucosa of SI
* Hosts:
* T. vulpis - dogs
* T. campanula, serrata - cats
* Dist: worldwide
* Morph:
* Adults - whiplike
92
Describe the lifecycle of Trichuris spp.
* **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
Describe the clinical signs and disease process caused by Trichuris spp.
* 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
How do you diagnose Trichuris spp. infections?
* fecal exam - high spec grav
* long prepatent period - may show C/S prior to eggs in feces
* eggs shed intermittently
95
How do you treat Trichuris infections?
* Drontal Plus (febental, pyrantel, praziquantel)
* fenbendazole
* HW preventatives also approved for whips: Interceptor (Plus), Sentinel (Spectrum), Advantage Multi, Trifexis
96
Describe Filaroides hirthi/F. Osleri (lungworm/tracheal/bronchial nodular worm)
* 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
Describe the Filaroides lifecycle
* 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
What parasite is this?
Filaroides osleri - tracheal nodules
99
How do you diagnose Filaroides spp.?
* Fecal exam, sputum
* Baermann or float?
* radiography
* endoscopy
\*often misdiagnosed as kennel cough
100
How do you treat Filaroides spp.?
* F. Osleri
* fenbendazole, ivermectin, doramectin, oxfendazole, thiabendazole, remove nodules
* F. Hirthi
* albendazole, Fenbendazole, ivermectin
101
Describe Aelurostrongylus abstrusus (feline lungworm)
* 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
Describe the life cycle of A. Abstrusus
* 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
Describe the clinical signs and disease process caused by A. Abstrusus
* 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
Which egg belongs to which parasite?
* Top left - Trichuris (smooth shell, symmetrical plugs, polar rings, brown)
* Top right - Pearsonemia (asymmetrical plugs, light yellow)
* Eucoleus eggs are almost clear
105
How do you diagnose and treat A. Abstrusus?
Dx: fecal exam - L1s, thoracic rads
Tx: Fenbendazole +/- prednisolone, moxidectin + imidacloprid, ivermectin?
106
Describe Angiostrongylus Cantonensis (rat lungworm)
* 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
Describe the life cycle of A. Cantonensis
* 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
Describe canine neural angiostrongylosis
* Progressive neuro signs - paralysis, headache (humans)
* history of eating IH
* eosinophyllic pleocytosis in CSF
109
How do you diagnose and treat A. Cantonensis?
Dx: CSF ELISA? PCR? , necropsy
Tx: supportive care
110
Describe Dracunculus insignis (guinea worm of dogs - serpent on the stick)
* Habitat: subcutaneous tissues
* DH: dogs, foxes, cats, raccoons, mink
* IH: copepod (Cyclops spp.)
* Paratenic host: frog
111
Describe the life cycle of D. Insignis
* 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
What are the clinical signs of a D. Insignis infection?
Painful skin ulcers
113
How do you diagnose and treat D. Insignis?
Dx: observe female under skin, coax L1 from blister via water
Tx: Fenbendazole, ivermectin
**\*best if treated w/in 90d PI**
114
Describe Dirofilaria immitis (canine heart worm)
* 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
How do you differentiate D. Immitis from A. Reconditum?
116
Describe occult D. Immitis infections
* 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
Describe microfilarial periodicity
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
What are the stages of D. Immitis?
119
Describe the life cycle of D. Immitis
120
Heart worms are not detectable *consistently* using most test procedures until they are _____ months old
6-6.5
121
How many mosquito vectors exist for D. Immitis?
* L3 in at least 70 species
* 23 species **can transmit heartworm**
* **14 species are common vectors**
122
Describe the clinical signs caused by heart worm disease
* 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
How do you diagnose heart worms?
* **Detection of antigen**
* **detection of circulating Mff**
* imaging
124
When do dogs become Ag-positive vs. Mff-positive?
* Ag-positive: 5-7 mo (unless on macrocylic lactones and miss doses)
* Mff-positive: 6.5 mo
125
True or false: Pets receiving macrocyclic lactones may never develop Mff or they may appear only transiently in small numbers
True
126
When should antigen testing be performed for D. Immitis?
* **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
When should you retest for the D. Immitis antigen?
* 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
What are some reasons you might have a positive Ag test result and negative Mff result?
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
What are some reasons you might have a negative Ag test result and positive Mff result?
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
What are some reasons you might have a variable Ag test result and negative/positive Mff result?
1. Fluctuating antigen level due to **number of female worms, age of worms, or quality of sample**
131
What is Wolbachia?
* **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
How do you treat heart worms?
133
When is the susceptibility gap for treating D. Immitis?
Days 30-100 - **not susceptible to either treatment**
134
What are some alternatives to immiticide/Diroban?
* 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
How do you treat Mff?
* Moxidectin
* Ivermectin
* Milbemycin
* Selamectin
136
Why might you omit Mff treatment?
With really high Mff counts - uses ivermectin, milbemycin at low doses
137
Describe Heartworm-Associated Respiratory Disease (HARD)
* 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
How do you diagnose feline heart worm disease?
* 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
What is the prognosis for feline heartworm disease?
* _\>_80% survive infections
140
Compare and contrast feline and canine heartworm disease
141
What do each of these spots show results for on a 4DX?
