Bacterial Enteritis in poultry

What is Bacterial Enteritis?

Bacterial enteritis (BE), also commonly referred to as Dysbacteriosis, Dysbiosis and Small Intestinal Bacterial Overgrowth (SIBO) is a disease observed in poultry which entails extreme inflammation and pathology in the gastrointestinal tract.

Due to similar pathologies in the intestine, Bacterial enteritis can commonly be confused with coccidiosis and Necrotic Enteritis, which are two entirely different diseases (see here for our article on coccidiosis). Misdiagnosis can lead to use of antibiotics or anticoccidials when not needed, which can lead to resistance issues. 

Unlike coccidiosis and necrotic enteritis, bacterial enteritis does not present identifiying lesions. Different Eimeria species (coccidiosis) produce very unique lesions and necrotic enteritis pathology is also very obvious (necrotising tissue in the intestines). Therefore, bacterial enteritis can only be diagnosed through an evaluation of gut health. There are multiple scoring systems around, which give a ranking based on evaluation of a number of parameters to how likely the pathology seen is actually due to BE. Similarly, in coccidiosis and necrotic enteritis scrapings can be taken and microbiological tests can be performed to diagnose these pathogens. This is not the case for BE, as it does not have a singular clear cause, but is thought to occur due to a cascade of events which damage the gut health and pre-dispose it to become unbalanced. 

What causes BE?

The cause of BE is thought to be multifactorial; a combination of microbial, bad management, feed and stressors on the gut such as parasite infections like coccidia and mycotoxins.  For instance, infection with coccidia will cause damage to the intestinal lining, and it will become inflamed. This damage to the lining can in turn provide a better environment for commensal bacteria to thrive, who might otherwise not cause any pathology. This enables the bacteria to colonise the gut and cause a number of pathologies. 

Other causes could be infection with a virus or mycobacterium or an oversupply of nutrients from feed, again providing an environment favouring bacterial growth. This allows certain bacteria to colonise, meaning the gut microbiota is out of balance. Infection with these parasites and pathogens cause damage and inflammation to the gut, leading to poor digestion and absorption of nutrients for the bird, leaving a less functional gut.

How do I know if my poultry have BE?

Typical signs of BE include: 

  • Wet litter
  • Diarrhoea 
  • Feed intake stable when should be increasing ( in growing birds)

However be careful, as these signs are also common to other diseases such as coccidiosis.

Necropsy can also show signs of BE, and these are what is used to evaluate BE typically;

  • Gut tone (flaccidity of wall)
  • Gut wall being thin/weak
  • Inflammation present
  • Blood vessels dilated
  • Excessive fluids
  • Ballooning of gut

It is not necessary for all of these pathologies to be present for a bird to have BE. Similarly, these can also be signs of other diseases/infections. 

BE can be inferred by a process of elimination. If birds are clear for coccidiosis, mycotoxins and other typical bacterial infections and carry these signs and pathologies, it is likely that they have BE.

How can I prevent BE?

Try to prevent BE by targeting the initial causes: 

Prevent cocccidosis by using anticoccidials in feed, vaccines, routine screening, good housekeeping. 

Prevent an encouraging environment in the gut by ensuring suitable feed not rich in nutrients vital for disease causing bacteria

Reduce gut stressors such as mycotoxins and bacteria using routine testing, ensuring sanitary feed, feeders and drinkers, and not mixing flocks. Good cleaning between flocks and mucking out can also aid with this.

Work on management strategies buy ensuring cleanliness, routine testing and screening, treating diseases to prevent outbreaks, getting animals found dead necropsied and sick animals looked at by the vet. 

General good gut health can be ensured by reducing general stress to birds, ensuring feed and water is in constant supply, there are no loud stressors, minimal handling and minimal bullying. 

References: VetWorks Poultry Gut Health Training, Belgium 2018.