Diseases / Miscellaneous / Multi-factorial / Metabolic Diseases / Chronic Wasting Disease of Deer and Elk / Detailed Disease Description:

< > Literature Reports of SIMILAR DISEASES for CWD of Deer and Elk:

Similar Diseases

Editorial Overview (Editorial Overview Text Replicated on Overall Disease page - CWD of Deer and Elk)
  • The main signs of CWD are weight loss and nervous signs. Therefore any disease which causes weight loss or nervous signs must be considered as a differential of CWD, and CWD must be considered as a differential diagnosis in other disease causing weight loss or nervous signs.
  • Seasonal changes in weight are normal in these species, which may mask early weight loss.
  • Poor nutrition, which may occur in wild deer during winter or drought conditions, is probably the commonest cause of weight loss.
  • Aspiration pneumonia may occur as a result of CWD, therefore CWD must be considered if necropsy findings indicate aspiration pneumonia.
  • "Sudden death", for example following handling, or unusual losses due to trauma, may also occur in animals with CWD.
  • Enzootic haemorrhagic disease (EHD) may cause sudden death to chronic disease, with signs including anorexia, lethargy, excess salivation, weakness and incoordination, all of which may be seen in cervids with CWD. Also, as with individuals affected with CWD, affected animals may often be found near water. However other signs seen in EHD are not typical of CWD.

Limited data on other TSE diseases is provided in literature reports below the information on CWD. Information on these diseases within the " Chronic Wasting Disease of Deer and Elk" volume of Wildpro is provided for comparative purposes and is not intended to be comprehensive.

See below for listings of other diseases (particularly those causing weight loss and/or neurological signs).

Data Source Information CWD of Deer and Elk
  • Prior to the diagnosis of CWD, initial cases in captive Odocoileus hemionus - Mule deer at a wildlife research facility in Colorado were thought to be related to captivity - factors such as nutritional deficiencies, toxicity or stress due to confinement. (J64.11.w3)
  • Differential diagnoses include all ill-thrift and nervous disorders, including for example ryegrass staggers, chronic form of malignant catarrhal fever, fading elk syndrome, polioencephalomalacia, copper deficiency, abomasal/omasal ulceration in adult deer. (P41.14.w1)
  • "Differential diagnoses include a wide variety of disease that cause CNS disease and/or emaciation." (J64.21.w17)
  • Enzootic haemorrhagic disease (EHD) may cause sudden death to chronic disease, with signs including anorexia, lethargy, excess salivation, weakness and incoordination, all of which may be seen in cervids with CWD. Also, as with individuals affected with CWD, affected animals may often be found near water. However other signs of EHD such as hyperaemia of the skin and mucous membranes, swelling of the face, conjunctiva and neck, bloody diarrhoea, lameness and coronary band haemorrhage are not signs typical of CWD. (B209.3.w3)
  • Aspiration pneumonia may occur due to CWD, probably related to excess salivation and difficulties in swallowing. If a cervid is diagnosed at necropsy with gross lesions of aspiration pneumonia, the brain must examined histologically to rule out CWD as the underlying cause of the aspiration pneumonia. (J64.21.w17)

Diseases causing weight loss include (but are not limited to):

  • Poor nutrition (energy or protein deficiency) may cause severe weight loss and emaciation. (B319) Food may be inadequate for wild deer during drought conditions or in the winter months.
  • "Fading elk syndrome" a common problem of farmed elk in New Zealand, is characterised by chronic loss of weight, ill-thrift and death. (B319, J195.17.w1)
  • Cobalt deficiency causes loss of appetite and therefore weight loss, emaciation and weakness. (B319)
  • Copper deficiency, seen mainly in young deer, may cause ill-thrift, diarrhoea, anaemia, bone fragility, lameness, joint swellings, a rough, dry pale coat and sudden death. (B319)
  • Selenium deficiency may cause ill-thrift. (B319)
  • Phosphorus deficiency may cause poor growth as well as pica, infertility and osteodystrophy. (B319)
  • Abomasal/omasal ulceration. May be found dead, due to perforation and acute diffuse peritonitis. Acute gastric haemorrhage may result in depression, cessation of feeding, separation from the group and reluctance to move.(P41.14.w1)
  • Gastrointestinal helminthiasis. (J231.46.w1)
  • Dental attrition (J64.21.w17)
  • Peritonitis. (J64.21.w17)
  • Pneumonia. (J64.21.w17)
  • Malignant catarrhal fever, chronic form. (J231.46.w1)
  • Johne's disease (weight loss and rough coat together with diarrhoea and green faecal staining around the anus/hind legs. (J231.46.w1)
  • Stress e.g. due to confinement of wild deer. (J64.11.w3)
  • Abomasal impaction may result in chronic ill-thrift with weakness and anorexia. (B319)

Diseases causing nervous signs include (but are not limited to):

  • Ryegrass staggers may cause signs ranging from slight head tremor, lethargy and anorexia to excited uncontrolled gait, collapse and convulsions. (B319)
  • Ergotism may cause depression, drowsiness, a staggering gait and a tendency to fall, prior to the onset of convulsions. (B319)
  • Botulism may cause progressive incoordination, ataxia and finally recumbency, due to muscle weakness and paralysis. In peracute cases the animal may just die suddenly. (B319)
  • Enzootic ataxia due to copper deficiency, seen mainly in young deer. (B319)
  • Lead poisoning may cause ataxia with muscle tremors, as well as apparent blindness, jaw champing and frothing at the mouth. (B319)
  • Other toxicities may cause nervous signs. (B319)
  • Head trauma may cause nervous signs. (B319)
  • Cerebral abscesses may cause a variety of neurological signs (J64.21.w17, B319)
  • Encephalitis or meningitis.  (J64.21.w17)
  • Polioencephalomalacia (cerebrocortical necrosis). Neurological signs including staggering, ataxia, head pressing, blindness, recumbency and clonic convulsions. (P41.14.w1, J64.21.w17, B319)
  • Malignant catarrhal fever may cause ataxia. (B319)

Other TSE Diseases

Transmissible Mink Encephalopathy

Mustela vison - American mink:

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Ovis aries - Domestic sheep:

  • In many cases the signs are clinically distinct (behavioural changes, tremor, pruritis and incoordination, progressing to recumbency and death) and easily recognised. In the early stages differential diagnosis include:
    • For itching and rubbing, ectoparasites such as mite or lice infections. These may be eliminated by parasitological examination. (J64.11.w4)
    • Pseudorabies (Aujeszkys's disease): this has a very short clinical course (36-48 hours) in ruminants and includes a high fever. (J64.11.w4)
    • Rabies, particularly if the clinical course has been less that ten days. In animals with such a short clinical course this possibility should be ruled out (in rabies-affected areas) by examination of the brain in a specialist laboratory. (J64.11.w4)
    • Listeriosis. Usually a short clinical course and fever, often with circling.(J64.11.w4)
    • Maedi-visna (ovine progressive pneumonia). May be ruled out using serological testing.(J64.11.w4)
    • Toxicity (chemical or plant) may be difficult to rule out ante-mortem. Liver function tests may be useful as may specific tests for toxins such as lead. (J64.11.w4)
    • Hypomagnesaemia. This has a short clinical course and may be diagnosed by the level of magnesium in plasma. (J64.11.w4)

Bovine Spongiform Encephalopathy (BSE):

Bos taurus - Domestic cattle:
  • Behavioural changes may suggest hypomagnesaemia or nervous ketosis (differentiation by lack of response to treatment in cases of BSE). Listeriosis (but clinical course short, requiring euthanasia within 15 days). Also lead poisoning, cerebrospinal abscess, other space-occupying lesions of the central nervous system, and spinal trauma. (J3.123.w2)
  • Other progressive neurological diseases. Primary differential diagnoses on the basis of clinical signs include hypomagnesaemia, nervous acetonaemia, rabies, lead poisoning, listeriosis, polioencephalomalacia and tremorigenic toxins. (B207)

Felis catus - Domestic cat:

  • Infectious diseases such as FeLV, FIV, feline coronavirus infection and toxoplasmosis. These can be diagnosed by serological examination. Thiamine deficiency is unlikely in cats fed proprietary diets designed for domestic cats. Lead poisoning (haematological abnormalities would be demonstrable) Hepatic encephalopathy (would produce abnormal hepatic function and systemic illness). CNS neoplasia or vascular accident would be expected to produce focal neurological signs. (J3.127.w4)
  • Infectious diseases FeLV, FIV, feline coronavirus infection and toxoplasmosis, trauma, thiamine deficiency, intoxications and metabolic disturbances (e.g. hepatic or renal encephalopathy). (J3.129.w3)

Creutzfeldt-Jakob Disease (CJD):

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New variant Creutzfeldt-Jakob Disease (nvCJD):

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Authors & Referees

Authors Dr Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referee Suzanne I Boardman BVMS MRCVS (V.w6)

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