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Module 14

AVS 201Equine Strangles

Equine Protozoal MyelitisRhodococcus Equi

Corynebacterium pseudotuberculosis

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Equine Strangles

Etiology Streptococcus equi

equi clinical disease only

in horses, donkeys,and mules. It is agram-positive

capsulated -hemolytic Lancefieldgroup C coccus

obligate parasiteand a primarypathogen

Also called Equinedistemper

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Equine Strangles

Transmission fomites and direct contact

with infectious exudates. Carrier animals ideal environmental

circumstances, theorganism can survive 7-9weeks outside the host.

barn facilities used by

infected horses should beregarded as contaminatedfor ~2 mo after resolution of an outbreak.

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Equine Strangles

Clinicals signs Incubatioon 3-14 days (103-106F [39.4-41.1C]).

mucoid to mucopurulent nasal discharge,depression, and submandibular lymphadenopathy.

Older animals with residual immunity mucoid nasal discharge, cough, and mild fever.

Metastatic strangles ( bastard strangles) ischaracterized by abscessation in other lymphnodes of the body, particularly the lymph nodesin the abdomen and, less frequently, the thorax.

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Equine Strangles

Diagnosis Culture and ID

Treatment Abscess drainage Warm compresses Antibiotics if resp

compromise ABS suppress lasting

immunity Bastard strangles

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Equine Protozoal Myelitis

Etiology Protozoan

Sarcocystis neurona

definitive (predator)host opossum

Intermediate hosts Nine-banded

armadillos, stripedskunks, raccoons, seaotters, Pacific harbor seals, and domesticcats

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EPM Clinical Signs

Ataxia (incoordination), Spasticity (stiff,stilted movements), abnormal gait or lameness

Incoordination and weakness which worsenswhen going up or down slopes or when headis elevated

Muscle atrophy, most noticeable along thetopline or in the large muscles of thehindquarters, but can sometimes involve themuscles of the face or front limbs

Paralysis of muscles of the eyes, face or mouth, evident by drooping eyes, ears or lips

Difficulty swallowing Seizures or collapse Abnormal sweating Loss of sensation along the face, neck or

body Head tilt with poor balance; horse may

assume a splay-footed stance or lean

against stall walls for support

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EPM

Diagnosis Immunoblot (Western blot)

test for S neurona on Serumor CSF

Treatment Specific antiprotozoal drugs 0% of horses improve with

treatment

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Rhodococcus equi

Clinical Signs subacute to chronic suppurative

bronchopneumonia, pulmonaryabscessation, and suppurativelymphadenitis.

most foals are lethargic, febrile, andtachypneic.

Cough purulent nasal discharge - less common. Thoracic auscultation

crackles and wheezes Intestinal andmesenteric abscesses are the mostcommon extrapulmonary sites of infection.

Less common - abdominal involvementoften present with fever, depression,anorexia, weight loss, colic, and diarrhea.Intestinal lesion are characterized bymultifocal, ulcerative enterocolitis.

prognosis for foals with abdominal forms of R equi is less favorable than for those withpulmonary disease.

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Rhodococcus equi

Diagnosis Bacterial culture of

transtracheal wash definitivediagnosis.

Cytology intracellular coccobacilli

Treatment Erythromycin & rifampin 80% survive with treatment 80 % die w/o appropriate AB

therapy Hyperimmune serum

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Corynebacteriumpseudotuberculosis

Clinical signs peak incidence in late summer

and fall abscessation of the lower

pectoral region or ventralabdominal wall with secondarydissemination to internal organs.

diffuse or localized swellings,ventral pitting edema, ventral

midline dermatitis, lameness,draining abscesses or tracts,fever, weight loss, anddepression. Leukocytosis andneutrophilia may be present.

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Corynebacteriumpseudotuberculosis

Diagnosis Culture and identification

Treatment Lymphangitis and early abscess

swellings are treated with hot packs,poultices, or hydrotherapy.

Abscesses are lanced and flushedwith iodine solution.

Large abscesses require surgery. scrubbed daily with an iodophor

shampoo.

Penicillin or trimethoprim-sulfa antimicrobial treatment may prolong

the disease by delaying abscessmaturation.

Phenylbutazone relieves pain andswelling.