Also known as Avian intestinal spirochetosis
Treponaema occurs in North America, Europe and Australia. It affects all species of poultry of all ages. It causes intestinal spirochetes (spiral bacteria) of the genus Treponaema.
- Causes of Treponaema >
- Effects of Treponaema >
- Diagnosis of Treponaema >
- Treatment & Control of Treponaema >
Causes of Treponaema
Avian intestinal spirochetosis (AIS) is a subacute to chronic disease characterised by nonsepticaemic spiral bacteria of the genus Spirochaetacae of which Treponaema, Borrlia and Serpulina are pathogenic to animals. The disease is caused by a heterogeneous group of spirochaetes in the rectum and / or colon.
One avian intestinal spirochaetes, Serpulina hyodysenteriae, has been classified taxonomically. The remaining are unclassified but have morphological and biochemical features Indicating placement in either the genus Serpulina or Treponaema. They have been shown to infect all domesticated poultry and wild birds. Intestinal spirochaetes or poultry are anaerobic gram negative, helix-shaped bacteria.
Initiation and severity of clinical disease is influenced by management, nutrition, environment and genetics. Contributing factors include moulting, onset of egg production, poor feed quality and floor housing. Light laying breeds are more susceptible.
Effects of Treponaema
Avian intestinal spirochaetes can be divided into three pathotypes, causing: subclinical infection, mild to moderate or severe clinical disease clinical disease. In layers, wet faeces, diarrhea, pasted vents, retarded growth, delayed onset of lay, production faecal-stained or dirty eggs shells, reduced egg weight and reduced egg carotenoids content may all be evident.
In turkeys, broilers and broiler breeders are similar to those in layers except that growth retardation is more severe.
Diagnosis of Treponaema
Because spirochaetes can be normal flora or produce subclinical infections, characteristic clinical signs and lesions must be present in conjunction with visual demonstration of helical bacteria by dark-field light microscopy or for a presumptive diagnosis of AIS.
Confirmation of bacteria as spirochaetes should be distinctive through visualization of ultra-structural features, demonstration of spirochaetes antigens or by isolation in culture. Culture from faecal droppings or fresh caecal mucosa followed by further characterization is necessary to confirm a diagnosis. In poultry, identified spirochaetes from faecal specimens should be distinguished from other spiral bacteria such as Campylobacter, Arcobacter, Helicobacter and Spirillum. In case of chronic diarrhea or pasted vents, nutritional problems such as excess dietary salt, fats or soybean meal should be investigated. Other causes of chronic diarrhea include Enteric salmonellosis, coccidiosis and colibaccillosis.
Treatment & Control of Treponaema
Prevention
AIS is chickens is a mild disease, but prevention is still more economical than treatment. Preventive measures include decreasing contact with faeces by raising birds off floors, frequent changing of litter or manure removal, good insect and rodent control programs, and dietary minimis moulting stress, provision of high quality feed ingredients and use of biosecurity measures.
Treatment
For intestinal spirochaetes or commercial poultry, or chemo therapeutics efficacy varies between isolates. Use of 5-nitromidazoles in water at a concentration of 120 ppm for 6 days is generally effective, although re-treatment after 4.8 weeks may be necessary. In some field cases, neomycin has produced clinical improvement.
