Spirurids 2 - filarial worms Flashcards
True or False:
If a ferret is infected with heartworms, you can detect this infection with an antigen test.
TRUE
Unlike cats, ferrets develop high enough worm burdens that you can detect antigens in the blood.
What is a filarial worm?
Nematode tissue parasites transmitted by blood-sucking insects.
Microfilariae accumulate either in blood or connective tissue.
Where is Acanthocheilonema reconditum found?
East, Southeast, and Southern U.S.
What are the vector species of A. reconditum?
Fleas and lice
The presence of Acanthocheilonema in the bloodstream implies that the animal may have a flea or lice infestation.
Tails of Dirofilaria and Acanthocheilonema. Which is which?
Left: Dirofilaria. Right: Acanthocheilonema
Note the “button-hook” tail of Acanthocheilonema when fixed in formalin.
Name the distinguishing features of the heads of Dirofilaria and Acanthocheilonema
- Dirofilaria* has a tapered head.
- Acanthocheilonema* has a blunt head with a cephalic hook or “beak”
What is the intermediate host of Setaria sp.?
Mosquitoes
Culex and Aedes
These are Setaria equina adults taken out of a horse. Where do the adults live?
Peritoneal cavity
Where would you find the microfilaria of Setaria sp.?
Bloodstream
What is the prepatent period of Setaria sp.?
8-10 months
What is the scientific name of the umbilical worm of cattle?
Stefanofilaria stilesi
What is the intermediate host of Stefanofilaria stilesi?
Haematobia irritans, the horn fly.
In what age of cattle is Stefanofilaria stilesi most common?
Cattle <3 years old
Where do adult Stefanofilaria live?
Dermal lymphatics of ventral abdomen.
Do Stefanofilaria microfilariae enter the bloodstream?
No. They remain in the superficial lymphatics.
Where do Stefanofilaria L3 larvae develop?
In the vector host, Haematobia irritans
What are the clinical signs associated with Stefanofilaria infection?
Chronic focal dermatitis (caused by mff), especially around umbilicus
Alopecia
Skin thickening
Serum exudate
Lesions are non-pruritic
This lesion is on the ventral abdomen of a calf. What parasite can cause this?
Stefanofilaria stilesi
Lesions are caused by microfilariae migrating through the superficial lymphatics and the feeding patterns of the vector host.
How would you diagnose a Stefanofilaria infection?
Lesion location during fly season.
Microfilariae detected in skin scraping or biopsy.
What is the primary host of Onchocerca cervicalis?
Horses
Where do adult Onchocerca cervicalis live?
Nuchal ligament of horses
Encased in fibrous nodules
What is the primary host of Onchocerca gutterosa?
Ruminants
What are the vector species of Onchocerca spp.?
Biting midges and blackflies
(varies by species)
Where would you find the microfilariae of Onchocerca spp.?
Dermis
Especially in the ventral abdomen and umbilicus
