Pigeon Pigeon FeverFever

ControversialControversial

Feared Feared

MisunderstooMisunderstoodd

A pain in the

behind

Etiology Corynebacterium psuedotuberculosis

Soil-borne, gram-positive, bacillus, intracellular, facultative anaerobe

Cultures in ~48 hours

2 biotypes Biovar equi

Multiple strains Biovar ovis

Multiple strains

Epidemiology 3 general forms

External abscesses 96% Internal abscesses 2% Ulcerative lymphangitis 2%

Cellulitis with multiple draining lesions

Entry via abrasions and/or wounds to the skin or mucous membranes Summer sores (ventral midline dermatitis)

Horses, cattle, humans, sheep, goats

Epidemiology Transmission

Horse to horse contact Insects “Other” vectors Contaminated soil

“Contagious” Not as bad as Strangles Absolute quarantine not required

Survival times Up to 2 months in hay or shavings More than 8 months in the soil

Epidemiology Yearly fluctuations

Herd immunity Environmental factors

Rainfall Temperature

Hot, dry

Not definitively determined at this time

All breeds, all ages are at risk

Risk factors Appropriate environmental conditions

map review

<5 years or age

Horses in contact with others on summer pastures

Horses housed outside or with access to an outside paddock > stabled horses

Pathogenesis Incubation period

7 to 28 days

Intracellular survival

Toxins reduce disease fighting abilities Similar to that produced by the Brown Recluse spider

Recovery 2 to 4 weeks

Although rare, horses can develop persistent recurrent infections lasting for more than 1 year

External Abscesses Clinical signs

Edema - 100% of the time Lameness or stiffness

100% of the time location, location

Anorexia - general malaise Fever ~25% of the time Weight loss Non-healing wounds

External AbscessesLocation…

Internal Abscesses Clinical signs

Consistent with the involved organ or area Changes in lab work

Blood Abdominal fluid Thoracic fluid Urine Serology

Most commonly found in the liver or lungs

Internal Abscesses

Internal Abscesses

Diagnosis Index of suspicion

Culture Gold standard

Ultrasonography

Serology Internal abscesses

Ultrasonography

Treatment Time

“You want me to..............wait?!” Yeah…

lets allow the abscess to “cook” for a bit

Drainage Ultrasound guidance

Determine vascularity, depth, site

Treatment Antibiotics

Variable Penicillins, Sulfas Rifampin, Doxycycline

Antiinflammatories Bute, Banamine, Equioxx, Dexamethasone

Hydrotherapy Cold or warm

Survival Rates <1% mortality rate associated with

external abscessation with treatment

30 to 40% mortality rate associated with internal abscessation with treatment 100% without

Ulcerative lymphangitis Similar mortality to internal abscesses

Long-term recovery In some horses, it can take up to 1 year for

them to fully recover from the effects of pigeon fever

Some horses will never fully recover from the effects of pigeon fever They die They are chronically lame They can suffer irreversible damage to vital

organs

Any questions?

Up Coming Classes

September

30th Veterinary Medicine 101: I want to be a veterinarian

October

7th Forelimb Lameness

21st Hindlimb Lameness

November

4th Colic and GI Disease

18th Respiratory Disease

December

2nd Disease Recognition

Thanks for your time