Equine Parasites Exam II Flashcards
What are the pathogenesis and lesions associated with adult infection of Draschia megastoma and Habronema spp?
Gastritis
Nodules or tumors
What are the pathogenesis and lesions that can occur in a Draschia megastoma and Habronema spp larval infection?
1) Cutaneous habronemiasis and Cutaneous draschiasis
2) Ulceration
3) Granular conjunctivitis
4) Nodules in the lungs
What are the clinical signs of adult and larval infections of Drascia megastoma and Habronema spp?
Adults cause gastritis.
Larvae cause “summer sores” (cutaneous habronemiasis)
What is another name for cutaneous habronemiasis?
“Summer sores”
Why are fecal examinations for Habronema spp and Draschia megastoma not good diagnostic tools?
Because the eggs are thin-walled and collapse with a loss of buoyancy in routine fecal examinations.
What is the infective stage for Habronema spp and Draschia megastoma?
How does it get into host?
L3 is the infective stage.
Fly larvae eat the hatched L1 in dung, L1 to L2, fly larvae pupates, L2to L3, adult fly transmits L3 to host by depositing larvae on lips, eyes, wounds, or fly itself may be ingested by host.
What is the infective stage for Parascaris equorum?
The L2 in egg is the infective stage.
Describe the life cycle of Parascaris equorum.
PPP is 10-12 weeks. It has a direct life cycle and is ingested (per os). No transmammary or transplacental transmission.
Where is the site of infection for Parascaris equorum?
The small intestine.
Describe the pathogenesis and lesions of Parascaris equorum.
1) Perforation through wall of small intestine, liver, and lungs. Hepatic tracheal migration.
2) Intestinal obstruction. Obstruction can occur with immature populations.
3) Unthriftiness or production losses.
What are some clinical signs that present with a Parascaris equorum infection?
Coughing during migratory phase.
Unthriftiness in heavy to moderate infections in young animals.
What three ways are Strongyloides westeri transmitted?
Per os and percutaneously, by the heterogonic phase.
And transmammary, by the 4th day.
What is the site of infection for the larvae of Strongyloides westeri?
For the adults?
The larvae infect somatic tissues (arrested).
The adults infect the small intestines.
What are the clinical signs and pathogenesis of larval Strongyloides westeri infection?
Of adult infection?
Skin penetration by larval migration causes erythematous reaction.
Infection in skin can cause urticaria.
Adults can cause diarrhea.
What is the diagnostic tool for Strongyloides westeri and when can we expect to see the eggs in the young horse?
Fecal flotation methods.
Expect to see eggs in horses < 5 months old. Suspect eggs seen in an older horse are likely Strongyle eggs.
What is the common name for Strongyloides westeri?
Threadworm
What is the scientific name for the large pinworm?
Oxyuris equi.
Where is the site of infection for the Oxyuris equi?
The large intestine (dorsal colon)
What is the infective stage for Oxyuris equi?
L3 larvae in egg.
Where do gravid Oxyuris females lay their eggs?
They travel out of the anus and lay eggs around the perineum in a gelatinous substance.
What are the clinical signs and pathogenesis of a Oxyuris infection?
Pruritus and peri-anal irritation (from eggs and gelatinous substance)
What can be used to diagnose a Oxyuris infection?
Note broken hair at tail head
Adhesive tape method or perianal scrapings to diagnose infection.
The following describes which worm species:
Direct life cycle (PPP 4-5 months)
L3 in egg (oval with flat side) is infective
Little immunity development
Adhesive tape method
Can become issue especially in barns/stables
Peri-anal irritation (from gelatinous substance)
Broken hair at tail head
This is the Oxyuris equi. The large pinworm.
What is the common name for the Subfamily Strongylinae?
Large strongyles
Name three species of the subfamily Strongylinae.
Strongylus vulgaris
Strongylus edentatus
Strongylus equinus
What is the common name for the Subfamily Cyathostominae?
Cyathostomins or small strongyles
What are the larval migratory patterns for the large strongyles?
Strongylus vulgaris:
Strongylus edentatus:
Strongyles equinus:
S. vulgaris: cranial mesenteric and ileocolic arteries.
S. edentatus: liver and abdominal tissue.
S. equinus: liver.
Adults of the large strongyles are found where?
In the small intestines.
What are the pathogenic and lesion markers for the larval stage of Strogylus vulgaris?
1) Arteritis
2) Thickening of arterial wall
3) Thrombus formation
4) Infarction
5) Death
6) Aberrant migration
What are the pathogenesis and lesions of adult Strongylus vulgaris?
They are bloodsuckers and remove plugs of mucosa
What are the clinical signs of a larval Strongylus vulgaris infection?
Of the adult?
Larvae: thrombo-embolus; colic
Adult: anemia in heavy infections
Acute larval infection of Stongylus edentatus can result in what pathogenesis?
What about chronic larval infection?
Acute: fever, anorexia, constipation, reddish urine, can lead to death
Chronic: intermittent colic; no rise in temperature
What can the Strongylus equinus larvae cause?
Hemorrhagic tracts and damage to pancrease during larval migration
The following clinical signs are indicative of what subfamily infection:
Colic(?) most typical
Fever, anorexia, constipation, ect
Adults, in heavy infections= anemia
The subfamily Strongylinae (large strongyles)
For the small strongyles (Cyathostomins), what are the lesions and pathogenesis?
1) Larval Cyathostominosis, nodular cyathostomiasis, larval cyathostomiasis
2) Lymphocitic and eosinophilic infiltration
3) Catarrhal colitis
4) Protein losing enteropathy
What are the clinical signs associated with a Cyathostomins infection?
1) Chronic diarrhea occurs with and without weight loss and can be recurrent. Appearance of L4 in diarrheal fluids.
2) Seasonality
3) General debility, weakness, cachexia, edema
4) Severe weight loss
5) Intussusception and colic
What is coprophagia and why is it relevant to the small srongyles and young horses?
Coprophagia is the eating of feces.
It is the reason why eggs of small strongyles are found in the feces of horses < 6 weeks of age.
What is the epidemiology of small strongyles in northern temperate climate?
In southern temperate climate?
In northern: Larvae arrest during winter Emerge, adults in spring Egg counts increase in spring In southern: Larvae encysts during summer Transmission occurs during winter
Define resistance.
It is the survival of a treatment with an antiparasitic drug that is generally effective against the same parasite at the same dose and against the same stage of infection.
Tolerance of the approved dose of an antiparasitic drug to which they were once susceptible to is due to genetic mutations.
What is the common name for Dictyocaulus arnfieldi?
What are hosts to D. arnfieldi?
The lungworm
The donkey is the host however, horses can be infected too
What are the clinical signs of a Dictyocaulus arnfieldi infection in donkeys?
In horse?
Do not cause observable signs in donkeys.
Horse can develop a chronic, productive cough. Damage to pulmonary tissues can also occur.
The following describes which Trichostrogylidae genus and species?
In horses, adults do not reach sexual maturity and patency.
Cause damage to pulmonary tissues in horses.
Adults are long and slender and found in bronchi.
L1 and eggs are found in feces.
L3 is infective stage.
The donkey is the definitive host.
Dictyocaulus arnfieldi (lungworm)
The following describes which species belonging to the class Cestoda:
IH: orbarid/forage mite (cysticercoid)
PPP: 1-2 months
Eggs irregularly shaped, difficult to recover; ELISA
No seasonality
Praziquantel
The Anoplocephala spp.
The following describes which cestode species of equines? More common White, 4 cm, lappets Iliocecal valve: ulceration, occlusion Intussusception
Anoplocephala perfoliata
The following describes which cestode species in the equine?
Larger, 80 cm, no lappets
Small intestine
Less pathogenic
Anoplocephala magna.
What is the common name for Gasterophilus intestinalis?
Bot fly larvae or bot fly
How are Gasterophilus intestinalis and Gasterophilus nasalis differentiated?
Differentiated based on color and spines.
Third stage larvae of G. intestinalis are red with course spines.
Third stage larvae of G. nasalis are yellow with 1 row of spines on each segment.
Egg deposition and larval third stage locations are species specific. Where do both of thee occur for Gasterophilus intestinalis?
Egg deposition: on hair of forelegs and shoulders.
3rd stage instars: in non-glandular part of stomach and cardiac region
Egg deposition and 3rd stage instar locations for Gasterophilus nasalis is species specific.
Where do each of these occur?
Egg deposition: intermandibular spaces
3rd stage instar: around pylorus and duodenum
Which fly species is the IH for the horse eye nematode Thelazia lacrymalis?
This fly species is also a mechanical vector for viruses, bacteria, helminthes, and Protozoa.
Musca autumnalis.
The following clinical signs are a result of which fly species:
Annoyance can interfere with grazing.
Annoyance can result in a drop in performance.
Can result in eye disorders or conjunctivitis.
Musca autumnalis
The following life cycle details describes which insect species:
Eggs laid in damp, marshy ground
Eggs hatch in 2-9 days
4 larval stages completed 14-25 days up to 7 months
Pupae at edge of water
Flies emerge in 3-5 days
Females suck blood
Culicoides spp.
The following pathogenesis and lesions describe which insect species:
They are an annoyance
Transmit viruses of bluetongue and African horse sickness
Transmit helminthes (Onchocerca in horse and cattle)
Transmit protozoan parasites
Culicoides spp
The following feeding habits describe which fly species?
Their bite is painful
Feed mostly during daytime, locate host by vision and CO2.
Several small meals often taken from the same or different host.
Interrupted feeding behavior increases their likelihood of being mechanical vectors of disease.
Prefer dark objects, will bite through colored clothing
Tabanus spp.
The following ID points are descriptive of which order of insects:
Microscopic;
Order: Acari (Mites)
What is the infective stage for Eimeria leukarti?
The sporulated oocyst.
What are the steps of schizogony (asexual reproduction) in the protozoan life cycle?
1) Host ingests the infective stage, a sporulated oocyst.
2) Sporocysts are liberated and the sporozoites leave them.
3) Each sporozoite penetrates an epithelial cell and forms a trophozoite.
4) Trophozoites form a schizont (a structure consisting of a large number of elongated nucleated organisms known as merozoites).
5) when schizont is mature it and the cell will rupture and the merozoites escape and invade neighboring cells.
6) Schizogony may be repeated and the number of times depends on the species.
7) Schizogony terminates when the merozoites give rise to male and female gametocytes.
What species does the following pathogenesis and lesions describe:
In FH: non-pathogenic
In IH: pathogenic effect due to 2nd stage schizogony in vascular endothelium
In accidental host: pathogenic due to 3rd stage schizogony in nervous tissue rather than muscle
Sarcocystis neurona.
