Most known information on Corynebacterium pseudotuberculosis, or pigeon fever, does not reflect current disease trends. In recent years, the disease that was once considered endemic in California and dry, arid climates in the west has spread as far north as Washington state and has been reported in such eastern states as Kentucky and Florida.
Cases in California, Texas, and Oklahoma still top the charts in numbers, but pigeon fever is spreading to areas unfamiliar with the disease.
Though named for the often seen chest abscesses, reminiscent of a pigeon, swelling and abscesses can develop all over the body. However, as pigeon fever is transmitted through contact with contaminated soil or through fly bites, the chest, midline and groin areas are often common abscess sites.
Veterinarians in all states should be familiar with the clinical signs of this disease:
- External abscesses, often accompanied by swelling. Internal abscesses and ulcerative lymphangitis are the two other forms of the disease that, while less common, can be much more serious.
- Fever
- Edema
- Lethargy and/or depression
- Lameness
- Weight loss
If pigeon fever is suspect, TVMDL can conduct a bacterial culture on material collected from external abscesses.
If internal abscesses are suspected and there is no obvious sample for culture, a serology test may be useful to identify this form of the infection.
Veterinarians may submit a sample following these guidelines:
- Culture: Typical specimen is a culturette or sterile tube containing pus or abscess fluid.
- Corynebacterium pseudotuberculosis – Equine (SHI): 2 mL or more of serum in a sterile tube.
- Submit with cold packs for specimen validity.
- Ship for overnight delivery to the laboratory as soon as possible.
- Include horse’s complete clinical history.
- Note suspicion of pigeon fever in the history.
The use of antibiotics can potentially hinder the ability to isolate the organism.