Spirurids Flashcards
What are the filarial worms?
Tissue parasites transmitted from blood sucking insects
What do adult female filarial worms produce?
Microfilaria
What are the Genus of filarial worms we are concerned with?
Stephanofilaria
Acanthocheilonema
Oncocerca
Setaria
_____ is a filarial worm that is found mainly in the E/S/SE US
Acanthocheilonema reconditum
Acanthocheilonema reconditum must be differentiated from what when looking at microfilaria?
D. immitus (heartworm)
Acanthocheilonema reconditum uses what for an IH?
lice or flea
What is the lifecycle of Acanthocheilonema reconditum?
Adults are in SubQ tissues; release mff.
Mff are picked up by lice/flea and develop into L3 in lice/flea
deposited when eating
What is the infective stage of Acanthocheilonema reconditum?
L3
What is the filarial worm that is in the abdomen/peritoneum?
Setaria species
_____ is the IH of Seratia
mosquitos
What is the life cycle of Seratia?
Adults are in the peritoneal cavity producing mff.
Mff taken up by mosquitos and develops into L3.
L3 deposited at new host when mosquito feeds
_____ is an umbilical worm that is most common in cattle
Stefanofilaria stilesi
What is the vector of Stefanofilaria stilesi?
Horn fly
The adults of Stefanofilaria stilesi are where?
dermal lymphatics of ventral abdomen (Contribute to signs)
What is the classic sign caused by Stefanofilaria stilesi?
Focal dermatitis on the ventral midline around the umbilicus
What are the lesions of Stefanofilaria stelsi caused by?
Mff production; feeding habits of the vector
See alopecia, skin thickening, and serum exudate
What is the diagnosis for Stefanofilaria stelsi? Tx?
Lesion location during fly season/skin scrapings
No treatment approved; Ivermectin for mff
_____ is the parasite that is often seen embedded into ligaments or connective tissue
Onchocerca spp.
What is the name of the parasite that embeds itself into the horse’s nuchal ligament?
Onchocerca cervicalis
What is the name of the parasite that embeds itself into the nuchal ligament of ruminants?
Onchocerca gutterosa
Females in the Onchocerca classification produce _____. The Infectious stage is _____ that develops in the IH of ____
Microfilaria
L3
Biting midges or black flies
The microfilaria of Onchocerca accumulates where?
Ventral abdomen in the dermis
What clinical signs do Onchocerca adults cause?
NONE; asymptomatic
Dermatitis is associated with the mff. These can cause alopecia, pruritis, and eye lesions
Treatment/prevention of Onchocerca is best accomplished via….
Ivermectin to treat mff
Insect control for prevention
_____ is the Spirurid eye worm
Thelazia spp.
_____ is the Spirurid that is the eye worm of horses 1-3 years of age
Thelazia lacrymalis
Where are Thelazia adults located?
Conjunctival sacs/lacrimal ducts of host eye
Thelazia females produce eggs with _____. The egg is taken up by ____ on eye secretions where it develops into an infections ______
L1
Flies feeding
L3
How does Thelazia spread?
Fly deposits the infective L3 when it is feeding on new host
Thelazia clinical signs include
increased lacrimation, conjunctivitis, plugged lacrimal ducts
Thelazia diagnosis should include_____. When diagnosed treatment should be:
inspecting the eye for worms, esp the ventral surface of 3rd eyelid.
Removal of eye worms.
Cattle receive doramectin
Dogs: ivermectin
What is a Spirurid worm that can be found in the esophagus of dogs?
Spirocerca lupi
Spirocerca lupi definitive host is____. It is common where?
Dogs
Tropics/subtropics
Female Spirocirca lupi produce ___ which is shed in teh feces. It is then ingested by ______ where it develops into the infectious _____.
L1
coprophagious beetle (dung beetle)
L3
How is Spirocirca lupi acquired?
Intermediate host of dung beetles
Paratenic host of mice, chicken, lizard
Ingest the infective L3
Where do adult Spirocirca lupi reside?
Fibrous nodules in the esophagus/stomach
What is the main concern with Spirocirca lupi?
Anuerism in the thoracic aorta, this can rupture and cause sudden death
How would you detect Spirocirca lupi?
See L1 in fresh feces via fecal float/sedementation; will resemble a PAPERCLIP
T/F: The esophageal nodules caused by Spirocirca lupi can metastasize
TRUE; they can go to the lungs
What would a proper Tx for Spirocirca lupi be?
Doramectin; Moxidectin can be used as a preventative
You come across a parasite with a very pronounced collar around the cuticle. You determine it to be a Spirurid. What is the name? Where do the adults reside?
Physaloptera species
Stomach of the definitive host, which are carnivores
What would be two distinct features of Physaloptera rara?
Cuticle on the collar
2 very distinct caudal alae
Physaloptera adults are in the ____. Females lay eggs with ____. It is ingested by a _____ which is the IH. It then becomes the infective stage ______.
Stomach
L1
Coprhagious beetle
L3
T/F Physaloptera is also spread via paratenic hosts
TRUE; snakes are a major paratenic host for carnivores
Physaloptera signs include….
None, genearlly asymptomatic
Diagnosis and Tx of Physaloptera includes:
Fecal detection of Physaloptera L1
Tx: is manual removal and treatment with anthelmenthics
Spirurids that are classified as swine stomach worms include…
Physocephalus
Ascarops
Physocephalus and Ascarops are most common where?
Pretty much worldwide. Not uncommon in the MW, more common in the Southern and Western US
What is the definitive host of Physocephalus? Ascarops? Where do the adults reside in each?
Swine for both
Stomach for both
What is the IH for Physocephalus and Ascarops? What is the infective stage? What stage would be seen in fresh feces?
Coprophagious beetle (dung beetle)
Infective stage is L3
Egg WITH L1
What are signs for Physocephalus and Ascarops? What would be a good treatment?
Mild catarrhal gastritis
Ivermectin
Habronematida can best be described as…
Spirurid equine stomach worm
The Habronematida family includes these three parasites:
Habronema muscae
Habronema microstoma
Drashia megastoma
Where to Habronematida worms usually reside?
NEar the margo plicatus
The intermediate host for Habronema muscae and Draschia megastoma is _____ while it is ______ for Habronema microstoma
Common housefly
Stable fly
The larvae for these are actually the IH
T/F You can see either eggs or L1 from Habronematida in the feces
TRUE
Fly larvae ingest the L1 of Habronematida. It then becomes the infectious _____ in the fly. If it is deposited on the _____ of the horse its life cycle will complete; if not its a dead end
L3
Muzzle
An obvious sign of Habronematida is _________ that results from L3 being deposited on surfaces other than the muzzle
summer sores; these heal spontaneously after freezing
T/F Both Habronema and Draschia cause stomach nodules
FALSE; Only Draschia megastoma causes stomach nodules. The two Habronema do not
Diagnosis/Tx of Habronematida
Possibly find eggs in the feces
Control the flies and do periodic worming
This worm’s definitive hosts are the raccoon and/or mink and is known as the guinea worm or firey serpant
Drancunculus insignis
T/F Drancunculus insignis is a zoonotic threat
FALSE
Drancunculus has IH and Paratenic hosts. IH are _____ while PH are ____
Arthropod (copepod)
Frogs/fish
When the _____ of Drancunculus insignis is consumed by the definitive host it migrates to _______.
L3
Subcutaneous tissues
Females of Drancunculus are on the _______ of the definitive host and secrete a produce that produces a prominent ________.
Lower part of the leg
Blister
When the blister of Drancunculus insignis comes into contact with ____ it ruputres and releases _____
Water
L1; this can then be consumed by the Intermediate host restarting the life cycle
Drancunculus insiginis is best treated by…..
Manually removing the worms
