Horses: Ascarids, Pinworms, Draschia/ Habronema Flashcards
parascaris equorum morphology
equine ascarids
large stout worms
anteior opening w/ 3 lips
adults parasitic in S.I
parascaris equorum lifecyle
direct
infection by ingesting larvated eggs in contaminated pasture
tracheal/ somatic migration
parasite of foals
prepatent period 12 weeks
Golden brown, round, sticky eggs
parascaris equorum clinical signs
diarrhea
enteritis
respiratory issues and nasal discharge
dull hair & poor growth
extreme infections can be fatal!!
How can infection lead to death
large worm burden
worms grow faster than intestinal tract in foals
impaction colic
intestinal perforation and rupture
parascaris equorum treatment/ control
clean mares udder/ teats (clean nursing environment)
dedicated pastures for foals
-grazed by older animals with low FEC
drug therapy 2,4,6,8 months
-FBZ, pyrantel, macrocylic lactone
oxyuris equi morphology
equine pinworm
medium sized worms
long tail w acute distal end
muscular bulb esophagus
adults parasitic in cecum, small and large colon
horses of all ages affected
oxyuris equi lifecycle
direct
infection via ingesting embryonated egg
larvae hatch, penetrate colon, develop, return to lumen & reproduce
females deposit eggs perianal folds
5 month prepatent period
eggs flake off skin and adhere to objects
infective 4-5 days after development
oxyuris equi clinical signs
intense anal pruitis and itching
rubbing hind end
broken tail hair
behavioral issues
does oxyuris equi need to be differentiated from mange
YES
oxyuris equi diagnosis
oval/ elongate egg
“scotch tape” microscope slide
egg mass in tail hair resembles shaving cream
oxyuris equi treatment/ control
adult worms susceptible to treatment
-Pyrantel and IVM effective
no evidence durg resistance
successful treatment and attention to hygiene
strongyloides westeri
equine threadworm
small adult worms in S.I
-only females parasitic
homogonic and hetergonic lifecycle
foals infected via lactogenic route
-prepatent period 7 days!
also infected via ingestion L3 and percutaneous
are males parasitic for strongyloides westeri
NO! only females
strongyloides westeri clinical significance
primarily infection of foals
-eggs disappear from feces by 24 weeks
-Arrested in tissue for LIFE
strongyloides westeri clinical signs and treatment
diarrhea-dehydration
poor growth
treatment to remove adults S.I, supportive care
Draschia & Habronema
equine stomach worms
small worms
thin shell larvated eggs occasionally seen on fecal
penetrate mucosa and develop in stomach
Draschia & Habronema lifecycle
obligate indirect
transmission of infected larvae by fly intermediate
larvae in cutaneous wounds, warm/moist openings
adults in stomach, eggs/larvae passed in feces
-ingested by maggots, larvae grow to infective as fly develops
prepatent period 5 months
Draschia & Habronema clinical significance
disease process associated w deposition of larvae by fly
cutaneous harbronemiasis
granulomatous lesion
adult worms live in fibrotic nodules in stomach
worldwide distribution! IVM made rare
-fly control important
-single dose macrocyclic lactone sufficient
is there age associated immunity with parascaris
YES
t/f parascaris can infect foals if they ingest larvated eggs shed by previous years foals
TRUE
can an object, like a curry comb, facilitate spread of oxyuris
YES
which of these parasites is spread by an intermediate host?
equine stomach worms
