Pigeon Fever
Controversial
Feared
Misunderstood
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%


Entry via abrasions and/or wounds to the skin or
mucous membranes


Cellulitis with multiple draining
lesions
Summer sores (ventral midline dermatitis)
Horses, cattle, humans, sheep, goats
Epidemiology

Transmission





“Contagious”



Horse to horse contact
Insects
“Other” vectors
Contaminated soil
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


Recovery


Similar to that produced by the Brown Recluse spider
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 Abscesses
Location…
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



Antiinflammatories


Penicillins, Sulfas
Rifampin, Doxycycline
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