Avian Intestinal Spirochaetosis Bra ...

Avian Intestinal Spirochaetosis Brachyspira species infection in Laying Hens

Happenings / Clinical Signs

Egg Drop

  • Egg production declines gradually
  • Reduced egg production
  • Slight reduction in egg production


  • Wet droppings
  • Increased fecal water content
  • Increased fecal fat content
  • The ceca were gassy and the contents were frothy, fluid and pale


  • Feces smeared on feathers around the vent ("pasty vents")
  • Dirty feathers with droppings around the vent or Pasty vents

Shell quality

  • Dirty fecal-stained eggshells
  • Egg weight reduced

Internal Egg Quality (contents)

  • Paler yolks
  • Yolk colour decreased or yolk discoloration or paler yolks

The "mild to moderate clinical disease" spectrum is seen particularly in association with strains of Brachyspira intermedia, Brachyspira pilosicoli and Brachyspira alvinipulli. 

These infections tend to be associated with diarrhea and/or reduced egg production, but cecal changes are mild or inapparent.

Infections with Brachyspira intermedia in laying hens shows increased in fecal fat content, developed slimy, wet, frothy feces or hard wet droppings and produces significantly fewer eggs.

Brachyspira pilosicoli was associated with a reduction in egg production, diarrhea in up to 25%, wet droppings, feces smeard on feathers around the vent ('pasty vents'), lethargy and depression.

Brachyspira alvinipulli was associated where 5% of the hens had wet feces, clinical diarrhea, pasty vents and produced dirty, fecal-stained eggshell. Experimental infection resulted in yellow, golden or orange cecal droppings.

Causing Agents
Bacterial Intestinal Infection. Brachyspira intermedia. Brachyspira pilosicoli. Brachyspira alvinipulli.
Affected Systems/Organs
Digestive System. Large Intestine, ceca.
Transmission via arthropods, droppings
Mainly Affects
Egg Production and Egg Quality
Drug therapy. Vectors control. Biosecurity
Suggested Actions
  • Can be confirmed with clinical signs and gross lesions
  • Can be managed with feed additives, off-the-shelf medications
  • Diagnosis should be confirmed with rapid assays and/or a certified laboratory
  • Veterinary intervention is recommended

Impact on Egg quality


Impact on Liveability


Impact on Production


Overall Economic Impact


Y.M. Saif.2008.Disease of Poultry. 12th Edition.page 929

David E. Swayne. 2013.  Diseases of Poultry 13th Edition. page 1001

Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition.

Paul McMullin. 2004. A pocket Guide to Poultry Health and Disease. First Edition.

Steven Leeson, John D. Summers. 2008. Commercial Poultry Nutrition. Third Edition.

Donald D. Bell, Williams D. Weaver. 2009.  Commercial Chicken Meat and Egg Production. Fifth Edition.

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