Gastrointestinal disease in avian and exotic species

• Taking history for GI problems in exotics

  Diet

  Faeces -quantity? Appearance?which part of the GI tract is affected.

  Any recent changes?

  Inside/outside?

  Stress/Pain? - can cause immune suppression.

  Any new pets?
• Clinical exam for GI problems in reptiles

  Head to tail clinical exam, similar to dog with some differences:

  • Thin abdominal muscles so you can palpate organs easily. Transillumination sometimes possible (geckos).
  • Head and mouth examination very important.
  • Faecal analysis is routine. As part of regular health screen.
  • Look for metabolic bone disease.
• Clinical exam for GI problems in birds

  Head to tail clinical examination, main differences:

  • Observe the birds first before handling it.
  • Careful handling, do not restrict rib cage - can accidentally suffocate them.
  • Look at droppings in the travel cage.
  • Limited celomic palpation due to large rib cage.
• General clinical signs of GI problems in exotics - similar to all animals

  Reduced appetite/anorexia/dysphagia.

  Reduced faecal droppings/ constipation.

  Diarrhoea/Tenesmus/undigested faeces.

  Pain (e.g. changed posture).

  Lethargy/depression.

  Weight loss.

  Dehydration

  Haematochezia.
• General clinical signs of GI problems in exotics - differences to other animals

  Enlarged crops (birds) - doughy/watery on palpation.

  Fluffed up (birds)

  Heat seeking (reptiles) - trying to keep their body temperature up to keep the immune system working.

  Stomatitis (reptiles)

  Prolapses (reptiles)

  Body swelling (snakes).
• Clinical signs of GI problems in exotics - vomiting/regurgitation

  Vomiting only common in ferrets.

  Vomiting and regurgitation are not clinical signs seen in omnivorous rodents.

  Regurgitation in reptiles is often husbandry related.

  Regurgitation is very common in birds. It can be normal or an indication of disease.
• Clinical signs of GI problems in exotics - normal regurgitation in birds.

  Courtship behaviour (male psittacines) - can end up regurgitating uncontrollably at mirrors and can loose a lot of weight.

  Physiological cast formation (raptors)

  Crop milk feeding (pigeons).

  Fear excitement (vultures, penguins).
• Common GIT condition in reptiles

  Husbandry causes (most common)

  Bacterial e.g. mycoplasma

  Viral e.g. herpes, inclusion Body disease, adenovirus.

  Endoparasites e.g. oxyurids, ascarids and strongyles.

  Protozoa e.g. crytposporidium, coccidia, trichomonas.

  Neoplasia

  Impactions/obstruction e.g. dehydration, foreign bodies.

  Prolapses.
• Reptile husbandry causes of GIT problems

  Inappropriate temperature (usually too cold/ incorrect bulb type).

  Dehydration - droplets of water.

  Inappropriate or excessive quantities of food.

  Excessive handling after a meal (snakes).

  Ingestion of substrate and foreign material.

  Overcrowding/mixing of species makes infectious causes more likely.

  Poor hygeine.
• Body distension/ swellings for GIT problems

  Distension of the snakes body may indicate a recent meal, gravidity, neoplasia, abscess or organomegaly. Snakes get visible swelling when something is going on.

  1. Garter snake with hypertrophic gastritis due to cryptosporosis.
  2. Bull snake with dystocia (but could be constipation).

  
• Causes of GIT problems in reptiles - Crytposporidium

  Protozoa affecting the stomach and small intestinal.

  When the stomach is infected it causes vomiting, weight loss, and hypertrophic gastritis.

  When the small intestine is infected it causes diarrhoea, passing undigested food and weight loss occurs.

  Very infectious and progressive in snakes and lizards, and is difficult to treat as there is no effective treatment.

  Stomach will often swell, pass undigested food, large weight loss, very ineffective, is considered untreatable.
• Causes of GIT problems in reptiles - herpes virus

  Virus often involves multiple body systems.

  Clinical signs include necrotising stomatitis and enteritis.

  
• Causes of GIT problems in reptiles - inclusion body disease

  Viral cause. Often involves multiple body systems.

  Arenavirus effecting snakes. Spread by ectoparasites (mites).

  Boas = regurgitation, slow wasting and neurological signs.

  Pythons = Same signs but more rapid with an acute death.

  Affectes bearded dragons (usually juveniles). Causes anorexia, diarrhoea and wasting and neurological signs.
• Causes of GIT problems in reptiles - foreign bodies

  Commonly substrate impactions e.g. sand (most common), corncob, wood chip.

  Water gels designed for feeder insects. So keep these outside the vavarium.

  Tortoises seem to deliberately ingest white objects.
• Causes of GIT problems in reptiles - liver disease

  Hepatitis due to toxins, fibrosis, neoplasia as well as viral, bacterial, fungal or protozoal infections.

  Mild hepatic lipidosis can be considered normal.

  Pathological hepatic lipidosis often occurs secondary to:

  • Poor husbandry
  • Improper or lack of hibernation
  • Bacterial or parasitism infection
• What are the common causes of GIT problems in birds?

  Crop impactions and infections e.g. sour crop.

  Foreign body/lower GI obstruction.

  Systemic infections (e.g. viral)

  Endoparasites (especially backyard chickens).

  Dietary changes (diarrhoea) or poor diet

  GIT infection/ enteritis (e.g. bacterial/viral)

  Neoplasia

  Antibiotic overuse.
• What are the causes of abnormal regurgitation in birds

  Iatrogenic (medically induced).

  Organomegally - puts pressure on the GI tract and pushes food out.

  Infectious cause - bacterial, viral, parasitic, fungal.

  Obstructive GI tract.

  Crop stasis +/- infection - causes a backlog and cause food to come up.

  Plants (yew, rhododendron, range of house plants, avocado).

  Toxicity (e.g. lead, zinc, chcollate).
• Crop stasis - clinical signs

  Regurgitation

  Delayed crop emptying

  Sour odour (due to stagnant fluid) - yeast overgrowth.

  Inappetance, dehydration and lethargy.

  Sour crop can be a primary crop infection, or most commonly crop stasis complicated by secondary bacterial and/or fungal infection.
• Diarrhoea in birds

  Watery dropping are normal for some bird species e.g. nectar feeders (e.g. lorries) and waterfowl.

  The consistency of the faecal component of the droppings is affected by the diet.

  Dietary change may induce (temporary) diarrhoea.

  Confirm that it is diarrhoea and not polyuria?

  More often a systemic cause rather than bacterial gastroenteritis.
• What are the 3 parts of the cloaca?

  Proctodeum - where the gastrointestinal tract empties into and is stored until it is passed.

  Urodeum - where the reproductive tract comes into it but also the urinary tract.

  Coprodeum - the final storage section before everything is passed.
• Haematochezia in birds

  Blood in the cloaca could be coming from several different places, could be from the urinary, reproductive or GI tract, could also be coming from the cloaca itself.

  • Egg-laying problems
  • Cloacal papillomas or neoplasia or ulcers.
  • Infectious enteritis
  • Heavy metal toxicity (Kidneys).
• Cloacal prolapses

  Same principles for finding the cause of prolapse.

  Cloacal prolapses are fairly common.

  Rectal prolapses = due to enteritis, parasites.

  Oviductal prolapse = in egg-laying females that strain excessively.
• Stomatitis in birds

  Stomatitis = inflammation or irritation of the mucous membranes in the mouth.

  Differentials:

  • Candida (yeast)
  • Bacterial
  • Capillariasis (endoparasites).
  • Trichomoniasis (flagellated Protozoa)
  • Viral e.g. pox virus (wet form), pigeon herpesvirus.
• Proventricular dilation disease (PDD) - birds

  Caused by Bornavirus that mainly affects psittacine birds. Does not always cause clinical signs, birds may be carriers.

  Inflammatory disease of the GI tract and neurological systems.

  The damaged nervous system does not allow nutrients to be digested or absorbed. Causes and increase in the size of the proventriculus. This is a progressive fatal condition, no known treatment.
• Liver disease in birds - general principles

  Generally non-specific clinical signs - lethargic.

  Biliverdinuria is a strong indication of liver disease (green colouration of urate fractions of the excreta).

  Occasionally an enlarged liver can be palpated below the sternum.

  Polydipsia and vomiting are sometimes associated with liver disease.
• Liver disease in birds - common causes

  Bacteria (mycobacterium, chlamydiosis, salmonella ects).

  Viruses (polyomavirus, adenovirus)

  Protozoa (atoxaplasmosis, coccidia).

  Parasites (fluke, migrating nematodes).

  Toxins (mycotoxins, plants chemicals)

  Hepatic lipidosis is very common in obese birds (high fat diet)

  Amyloidosis (due to long term inflammation).

  Neoplasia - primary and secondary metastasis.
• Diagnostic options for birds with GI problems

  Haematology/ biochemsitry

  Imaging - radiography, CT, endoscopy, ultrasound.

  Crop and faecal cytology and bacteriology (culture and sensitivity)

  PCR testing - specific pathogen.

  Histology and FNAs

  Exploratory laparotomy/ Coeliotomy

  Post mortem for flock collection problems.
• Diagnosing GIT problems in birds - radiography

  Can see foreign bodies, organ enlargement, tumours. Contrast medium is very useful in birds and reptiles, can help identify obstructions and slow gastrointestinal motility.

  
• Diagnosing GIT problems in birds - Blood testing

  Haematology/ biochemistry

  • Can be sued to detect some things e.g. inflammatory process/infection, organ damage e.g. liver and kidney.
  • Can be ‘normal’ despite pathology of the GI tract.
  • Can help determine severity and help stabilise e.g. dehydration..
  • Can detect what organs/ systems are involved.
  • Always do a fresh blood smear as birds and reptiles have unucleated red blood cells, so send fresh sample to lab to count rather than running though a machine.
• Diagnosing GIT problems in birds - faecal testing

  Flotation parisitology to loo for endoparasites.

  Gram stain +/- negative culture to look for bacterial causes.

  Faecal PCR for specific pathogens such as bornavirus (PDD), chlamydophila (Psittacosis, 3 day pooled), cryptosporidium.
• Diagnosing GIT problems in birds - Mouth and crop testing

  Cytology/ wet prep or oral lesions or crop fluid. For stomatitis in birds.

  Trichomonas = mobile flagellated organism (high power magnification). Warming samples increases activity. Easy to diagnose in house.

  Candida = yeasts (low levels are normal.)
• Liver disease in birds - diagnostic

  Faecal examination(in birds might be green).

  Total body radiograph - enlarged liver? Can do transilumination in geckos.

  Haematological examination: PCV, WBC and differentiation; buffs coat for parasites.

  Biochemistry: total protein and albumin: globulin ratio.

  • Birds: GLDH, bile acids (AST, LDH).
  • Reptiles: none, LDH/ALT/ALP/GGT all widely distributed.
  • Rabbits: GGT more specific than ALT and ALP.
• Supportive care for GIT conditions in exotics

  Pain relief e.g. NSAID (meloxicam) and opioids:

  • Reptiles - morphine
  • Birds - Butorphanol
  • Small mammals: Buprenorphine

  Fluids (oral, S/C, IC, IV, IO) - IV is the ideal choice.

  Warmth for all species (specific preferred optimal temperatire zone of a reptile).

  Tube feeding birds and reptiles (high protein recovery diet).

  Liver supplements: lactulose, thyroxin, SAMe, sylmarin, L-cartinine (dogs/cat liver supplements).
• Drugs to treat specific underlying GIT causes in exotics

  Injectable vitamins appetite stimulant in reptiles.

  Antibiotics e.g. TMPS, doxycline, metronidazole. Culture and sensitivity is recommended.

  Antifungals e.g. oral nystatin for sour crop, oral amphotericin B for avian gastric yeast. For prevention use apple cider vinegar in drinking water, this will not work as a cure once sour crop has developed.Anthelmintics e.g. fenbendazole, ivermectin. Anti protozoal - metronidazole (also appetite stimulant in reptiles). Pro-kinetics - metoclopramide (in crop stasis)
• Drug cautions in exotics - ivermectin and metronidazole


  Ivermectin:

  • Will lill Chelonia. Safe for use in other species when used appropriately.

  Metronidazole:

  • Is used frequently for protozoal and bacterial infections in snakes, but king snakes and indigo snakes appear very sensitive to it (use lower doses if no alternatives.)
• Drug cautions in exotics - when no treatment is recommended

  Salmonella in reptiles

  • Commensal, doesn't cause clinical signs.

  Cryptosporidium in reptiles:

  • Don’t treat as there is not an effective treatment, often have to put them to sleep.

  PDD in birds - no effective treatment.

  With chickens where there isn't a licensed treatment in a food purchasing animal (supportive treatment only).
• Species differences with ‘normal’ bacteria in exotics

  Commensal bacteria of the oral cavity and cloacal in reptiles include Salmonella spp, E.coli, Psuedomonas spp, Klebsiella spp, Aeromonas spp and Citrobacter spp.

  These bacteria may also become pathogenic (often due to poor husbandry).

  Just because an organism is cultures does not mean it is the responsible pathogen.
• Salmonella spp in reptiles

  Generally considered a harmless commensal of the GI tract in reptiles (rarely pathogenic).

  Unsuccessful attempts to produce salmonella-free reptiles.

  Potential a significant zoonosis.

  Do not recommend treatment, to prevent resistant strains.

  Sensible to assume that all reptiles are carriers.

  Appropriate hygiene measures are important.
• Surgery to treat underlying specific causes of GIT problems in exotics

  Some diagnosis will need surgery wither instead of or after attempted medical treatment:

  • Foreign body/ impaction removal (laxatives and enemas may work in selected cases to avoid surgery).
  • Persistent or severe prolapses.
  • Surgical biopsies.
  • Endoscopic visualisation e.g. stomach ulcers, growths.
• Nutritional support in exotics - starving

  We do not starve exotic animals, with the exception of prior to a general anaesthesia for:

  • Birds - only fir crop emptying (budgie ~1hr, parrot ~3hr).
  • Reptiles - 24-72 hours but often not necessary as they are anorexic already.

  It is really important that we provide nutritional support to exotic animals suffering from GIT disease.