All about Fowl Spirochetosis (Brachyspira) disease

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Giving your flock plenty of space and a clean, dry, coop and run area with little stress is more than just a luxury for your birds; it's also a great way to help protect them against many diseases, including Spirochetosis. Spirochetosis can be caused by the Brachyspira or the Borrelia bacterium. Both are treatable using antibiotics--under a veterinarian's care. This article examines the type caused by Brachysprira bacteria:

Fowl Spirochetosis (Brachyspira) Also called
AIS, Avian Intestinal Spirochetosis, Avian Spirochetosis

Common in some areas

General signs -
Sometimes no symptoms. Other times, symptoms may include lack of appetite, lethargy, sleepiness, increased demand for water, weight loss or failure to grow, drop in laying, dirty eggs, pasting.
Cardinal or diagnostic signs -
Yellow or green watery droppings with a lot of white urates. Lab diagnosis.

Brachyspira spp, which are spirochetes (bacteria). Some species don't cause illness, such as Brachyspira innocens, while others are pathogenic, such as Brachyspira pilosicoli and Brachyspira intermedia.

Yes. Unlike the Borrelia form of spirochetosis, this is not tick-borne, but nonetheless, the bacteria can be picked up from scratching/foraging in fresh droppings or knocking them into the feeder, or from squabbling/picking that draws blood. It is thought that birds can also pick up the illness from fly populations.

Communicability to humans
No risk known.

Incubation period
3 to 12 days

No. Chickens that survive are not carriers, and are immune for some time to re-infection from the same bacteria.


Home treatment and/or prevention
Prevention: Reduce stress in the coop to reduce picking and squabbling. Provide plenty of space. Keep coop bedding dry and change it frequently. Keep feeders and waterers clean.

Treatment: No home treatment. Consult a vet.

Veterinary care
A vet can give you a firm diagnosis and treatment. Several antibiotics are quite effective against spirochetosis, but your vet will need to prescribe them and offer advice on the egg-discard period. Some types of Brachyspira do not cause disease, so if Brachyspira are detected in droppings, often the vet will decide to distinguish the species in order to make sure s/he is offering the correct treatment.

Variable. Some strains are quite mild. Others are severe.

Other conditions, illnesses and/or diseases with similar signs:
Loose droppings are common with other infections like coccidiosis and digestive issues. Fowl Spirochetosis (Borrelia) is quite similar. In most cases only lab diagnosis can tell them apart.