Clinical Parasitology Flashcards
What are the cestode (tapeworms) and trematode (flukes) associated with equine parasitology?
Cestode - Anoplocephala perfoliata
Fluke - Fasciola hepatica
what are the Nematodes associated with equine parasitology?
everything else
what are the 4 classes of anthelminthics used in equines?
Bendimidazoles
Macrocyclic lactones
Tetrahydropyrimidines
Praziquantel
what is the mechanism of Bendimidazoles?
acts upon fumarate reductase to interfere with carbohydrate metabolism
what are the examples of Bendinidazoles generic and trade
what is the mechanism of macrocyclic lactones?
increase cell permeability to Cl- > flaccid paralysis and death
what are the examples of macrocyclic lactones generic and trade?
what is the mechanism of tetrahydropyrimidines?
cholinergic agonist
what are the examples of tetrahydropyrimidines generic and trade?
what is the mechanism of praziquantel?
induce spastic paralysis - possibly via Ca channels, disrupts tegument
what are the examples of praziquantel generic and trade? what are the other drugs the trades are formulated with?
which of the anthelminthics are formulated with macrocyclic lactones?
praziquantel
what should be considered when deworming to avoid the “one-size-fits-all” approach?
age
immune status
geography and climate
population density
What age group of horses is Parascaris equorum primarily a concern in?
foals up to 6 months
At what age do most horses clear P. equorum?
6-12 months
what is the clinical syndrome associated with P. equorum?
intestinal impaction and rupture
What resistance does P. equorum have to anthelmintics?
widespread to macrocyclic lactones
early resistance to benzimidazoles and pyrimidines
what is the first line of defense in treating Parascaris equorum?
benzimidazoles
where does Strongyloides westeri inhabit?
SI of nursing foals
what are the 3 routes of infection in Strongyloides westeri?
skin penetration by L3
Ingestion from environment
Lactogenic transmission from the mare
How do foals with Strongyloides westeri often present?
asymptomatic
what do you treat Strongyloides westeri with?
Benzimidazoles - macrocyclic lactones
How do you prevent Strongyloides westeri in foals?
deworm mares at or just prior to foaling
what is the recommended deworming schedule for foals?
what is the clinical syndrome caused by large strongyles?
verminous arteritis
what is the most clinically signifigant large strongyle?
Strongylus vulgarus
where does large strongyles migrate to and what does it cause?
migrate to cranial mesenteric artery >
thrombosis and infarction > colic
How do you treat large strongyles?
macrocyclic lactones
what is the most severe clinical syndrome with small strongyles?
larval cyathostominosis
what causes larval cyathostominosis?
synchronous emergence of encysted L4 larvae > obliterating mucosal surface of GI tract
what do you treat small strongyles with?
moxidectin
what clinical signs are seen with small strongyles?
diarrhea, hypoproteinemia
what do you treat a debilitated animal that is infect with small strongyles with?
Panacur PowerPac (ivermectin) instead of moxidectin
where Anoplocephala perfoliata reside in horses?
ileocecal junction
what does Anoplocephala perfoliata cause?
ulceration and inflammation, colic, intussusceptions, ruptures
what do you treat Anoplocephala perfoliata with?
Praziquantel
where are Oxyuris equi found in horses?
adults in descending colon and rectum
eggs laid perianally
what do you treat oxyuris equi with?
ivermectin
What are Onchocerca cervicalis and Setaria equina transmitted by?
bloodsucking arthropods
what is the preferred site of Onchocerca cervicalis and Setaria equina?
Onchocerca - CT (nuchal ligament)
Setaria - abdominal cavity
what can result in verminous dermatitis?
Onchocerca
which equine parasite infection is clinically silent?
Setaria equina
which equine parasite can cause uveitis?
Onchocerca cervicalis
How do you treat Onchocerca cervicalis and Setaria equina?
macrocyclic lactones
what is another word for Habronema spp and Draschia spp?
stomach worms
what does Habronema spp and Draschia spp infect? (location)
wounds and mucocutaneous junctions
what type of inflammatory reaction does Habronema spp and Draschia spp cause?
massive inflammatory rxn
eosinophilic granulomas
“sulfur granules”
How are Habronema spp and Draschia spp leasions treated?
oral or intralesional steroids
How do you treat Habronema spp and Draschia spp?
macrocylic lactones
what are Gasterophilus spp. also known as?
bot larve
How do you treat Gasterophilus spp.?
macrocyclic lactones
How do horses get infected with Gasterophilus spp.?
infection by horse licking itself and ingesting eggs
what is another name for Thelazia lacrymalis?
eyeworm
What can Thelazia lacrymalis cause?
inflammation of lacrimal glands
resides in conjunctival sac
How do you treat Thelazia lacrymalis?
Benzimidazoles
What parasite do you often see when a horse lives with donkeys and mules?
Dictyocaulus arnfieldi
What is a diagnostic method for Dictyocaulus arnfieldi?
Baermann
How do you treat Dictyocaulus arnfieldi?
Macrocyclic lactones
what is the infective stage of Dictyocaulus arnfieldi?
L3
What can be used to treat Fasciola hepatica?
Triclabendazole
How do you approach individualized parasite control in horses?
fecal egg counts
fecal egg count reduction test
what is the treatment threshold for fecal egg counts?
200 EPG and greater
How do you calculate a fecal egg count reduction test?
what type of parasite do you not use fecal egg count reduction test for?
tapeworms
what are two diagnostic techniques for equine parasites?
McMaster’s FEC
fecal float
Label each egg that could be seen on a McMaster’s egg count
what is this?
what is the most significant concerns with equine parasites? (adults and foals)
Cyathostome resistance to benzimidazoles in adults
ascarid multi-drug resistance in foals
what should you test for if you have a older horse with a high egg burden?
PPID
