WA Livestock Disease Outlook - for vets

Supporting Australia's ability to sell livestock and livestock products

Australia’s ability to sell livestock and livestock products depends on evidence from our surveillance systems that we are free of livestock diseases that are reportable or which affect trade. To gather this proof of freedom, the Department of Agriculture and Food, Western Australia (DAFWA) investigates cases where livestock show signs of disease similar to reportable or trade diseases.

The WA livestock disease outlook – for producers (WALDO) is collated from information collected by DAFWA and private veterinarians as part of proving Australia’s freedom from those diseases and in 2015/16 allowed WA to access markets valued at $2 billion.

Recent significant cases submitted to DAFWA Diagnostic Laboratory Services

Case data from November 2016 to January 2017

Sudden death of 12 ewes in the Great Southern

  • Twelve ewes were found dead in a mob of 600 on a farm in the Great Southern. The ewes were in good condition and grazing predominantly ryegrass pasture.
  • When the mob was moved, two ewes began convulsing and died.
  • A postmortem performed on two ewes found congested lungs and rumens containing dry pasture and an unidentified green plant with oval, opposing leaves.
  • The rumen contents tested negative for annual ryegrass toxicity (ARGT) but positive for fluoroacetate.
  • Given the presence of neurological signs, the laboratory carried out exclusion testing for transmissible spongiform encephalopathies (TSE) and the results were negative.

Exclusion testing is vital to prove Western Australia’s freedom from significant diseases such as TSE. Producers and veterinarians can obtain subsidised testing under various programs for veterinarians to investigate animal diseases.

Read more on how you can participate in the TSE surveillance program.

Foot-and-mouth disease and bluetongue virus exclusion testing on a heifer in the South-West

  • An eight-month-old, white-faced heifer from a property in the South-West was presented to a private vet for investigation of erosive nasal and oral lesions, drooling and lethargy. Photosensitisation was suspected.
  • On examination, the heifer had increased respiratory sounds, pyrexia, reduced rumen sounds and an area of sloughing epithelium near the mouth with the appearance of sunburn. Erythema was noted on the ventral surface of the tongue and there was profuse nasal discharge and salivation.
  • Exclusion testing for foot-and-mouth disease (FMD) virus, vesicular stomatitis virus, bluetongue virus and bovine herpes virus type 1 produced negative results. Biochemistry showed mildly elevated liver enzymes which could support a diagnosis of photosensitisation along with the clinical signs.

The most likely way that FMD virus would enter Australia would be through the illegal importation of meat and dairy products or from overseas travellers entering with clothing, footwear or equipment that have been contaminated with the virus. Early recognition and reporting of FMD signs could help to minimise the impacts of an outbreak by minimising its spread.

Read more about recognising the signs of FMD.

Hendra virus exclusion on a property in the Pilbara

  • A 20-year-old mare presented with neurological signs, tachycardia, muscle tremors, weight-shifting on her feet and violent response to stimuli that led to seizures. The mare was euthanased.
  • Five days later, the paddock-mate, a six-year-old gelding, presented with similar clinical signs. He was treated and appeared to recover.
  • Flying foxes had been seen in the area and the water trough was located beneath a flowering eucalypt tree.
  • Samples were taken from the gelding and horses in neighbouring paddocks including bloods, nasal swabs, water, feed and hay. A provisional diagnosis of organophosphate or strychnine poisoning was given.
  • In the following two days, the gelding deteriorated with frequent and lengthening periods of collapse. He was euthanased and a postmortem was performed. The brain was included with the sample set.
  • Strychnine, fluoroacetate and organophosphate were not detected on a general toxin screen.
  • Testing at DDLS and Australian Animal Health Laboratory (AAHL) confirmed that all horses were negative for Hendra virus.
  • Further exclusion tests for the reportable diseases equine encephalomyelitis (eastern, western, Venezuelan) and West Nile virus were negative. Murray Valley encephalitis was also excluded.
  • Faecal testing of the gelding returned a positive result for ARGT. Hay samples (bought-in from the South-West) returned as high risk for ARGT while chaff samples were negative. Subsequent testing of hay from suspect bales returned a positive result for ARGT in eight out of 11 samples. 
  • When submitting hay samples to the lab, provide at least a 100 gram ‘grab’ sample from several places in a single hay bale and sample multiple bales.
  • Advise clients that a vendor declaration for brought-in hay, grain and chaff is recommended to ensure the feed they buy will not harm their animals.

If presented with a horse showing signs of Hendra virus that may have been in contact with flying foxes or horses from Queensland or New South Wales, contact DDLS – Animal pathology unit on +61 (0)8 9368 3351 or the Emergency Animal Disease hotline on 1800 675 888 for advice before handling or close contact.

Read more about managing the risk of Hendra virus in WA.