Equine Cardiovascular Diseases - Part 2

Flashcards covering key clinical, epidemiological, diagnostic, and therapeutic concepts for Dourine, Surra, and Ulcerative Lymphangitis from VMED 37 Equine Medicine Part 2.

What organism causes Dourine in equids?

Trypanosoma equiperdum

What feature makes Dourine unique among all trypanosomoses?

It is the only trypanosomosis that is not transmitted by an invertebrate vector.

How is Dourine primarily transmitted among equids?

Through breeding (venereal transmission), most commonly stallion-to-mare, via vaginal secretions, seminal fluid, and exudate from the penis.

What is the pathognomonic clinical sign of Dourine in horses?

Leukodermic "silver dollar" plaques ($2\text{ to }10\,cm$) on the skin, particularly over the ribs.

Which diagnostic method is the prescribed test for international trade regarding Dourine?

Complement Fixation Test (CFT)

Why is pharmaceutical therapy not recommended for horses infected with Dourine?

Infected animals may improve clinically after treatment but remain carriers of the parasite.

What dosage of Suramin is noted for treatment of Dourine?

$10\,mg\,kg^{-1}$ IV

What organism causes Surra in horses and other animals?

Trypanosoma evansi

How does Trypanosoma evansi reproduce within its host?

By longitudinal binary fission (it lacks kinetoplastic DNA).

Which biting flies serve as primary mechanical vectors for Trypanosoma evansi?

Horse flies (Tabanus spp.) and stable flies (Stomoxys).

Which Tsetse fly species transmits Trypanosoma evansi in areas around rivers and lakes?

Glossina palpalis

What is the typical incubation period for Surra in horses?

Generally ranges from $5\text{ to }60\,\text{days}$, with clinical signs most commonly appearing within $1\text{ to }4\,\text{weeks}$ after infection.

What is considered the most sensitive rapid method for diagnosing Surra?

HCT / Woo's technique (wet mount of the buffy coat area of a PCV tube after centrifugation).

What specific brain lesion is observed upon pathological examination of a horse with Surra?

Asymmetrical necrosis and gelatinous edema within the thalamus.

Which curative drugs can be used for treating Surra?

Melarsomine dichlorhydrate, Suramin, Quinapyramine sulfate, and Quinapyramine dimethylsulfate.

What is the primary bacterial cause of Ulcerative Lymphangitis (Pigeon fever) in horses?

Corynebacterium pseudotuberculosis

What are common synonyms for Ulcerative Lymphangitis in horses?

Dry land distemper, Pigeon breast, and Pigeon fever (False Strangles).

What are the characteristics of the exudate produced by Corynebacterium pseudotuberculosis abscesses?

Odorless, thick, tan, and blood-tinged.

How large can internal abscesses grow in horses affected by Corynebacterium pseudotuberculosis?

Up to $20\,cm$ in diameter.

Which blood test is used specifically for diagnosing Corynebacterium pseudotuberculosis infection?

Synergistic hemolysis inhibition test

Which systemic antibiotic is considered most effective for treating Ulcerative Lymphangitis?

Doxycycline

Which pain medications are used to relieve pain and swelling from deep abscesses in Ulcerative Lymphangitis?

Phenylbutazone and flunixin meglumine.