The WA Livestock Disease Outlook provides information about recent livestock disease cases in Western Australia and diseases likely to occur in the next month. Calling a vet to investigate diseases when they occur provides surveillance evidence to our markets that we are free of reportable and trade-relevant diseases.

Recent animal disease investigations

Investigation of unusual disease signs helps to rule out an exotic disease - scrapie

• An abattoir vet examined a sheep in poor condition, lying on its side and tremoring. It appeared blind and had abnormal eye movements.
• The animal was euthanased humanely and the vet performed a post-mortem to investigate the cause of disease.
• The vet collected brain samples as well as the usual samples because of the animal’s unusual behaviour to test for the exotic disease, scrapie.
• Samples were submitted the DPIRD laboratory and testing showed the sheep had ovine Johne’s disease [2] (OJD - a reportable disease [3]).
• OJD is a wasting disease that affects mainly sheep, and to a lesser extent goats. It is caused by the sheep strain of the bacteria Mycobacterium paratuberculosis. Sheep infected by the OJD bacteria may take three to six years to show signs of the infection. Once the disease is seen, affected sheep progressively lose condition and die over a six to 12-week period.
• See the DPIRD website for advice on OJD prevention and management [4].
• The brain showed no evidence of transmissible spongiform encephalopathy (TSE - scrapie [5] in sheep). These test results provide evidence to support Australia’s claim of freedom from scrapie, and is needed for our continued access to markets.
• Producers and private vets can access rebates for submitting suitable samples for TSE exclusion - see the transmissible spongiform encephalopathies [6] webpage.

African swine fever and classical swine fever rule-out in pigs that died suddenly

• African swine fever [7] is a highly contagious virus that causes high death rates in pigs. The disease has been spreading across Europe and Asia since a large-scale outbreak in China in August 2018, and was most recently reported in our near neighbour Papua New Guinea. If the disease entered Australia, it would severely impact our pig industries as there is no vaccination available and the disease is difficult to eradicate.
• Early detection would be vital to our chances of eradication if an outbreak occurred in Australia. Always call a vet to take samples to rule out the disease in sick pigs that display signs similar to African swine fever or other reportable diseases. Read more about African swine fever disease signs [7].
• In this case, a private vet investigated two dead and 50 sick pigs in a group of 200. Some of the sick pigs had recently started tremoring and others had lost body condition.
• The submitting vet had made a provisional diagnosis of salt toxicity and lab testing at DPIRD supported this, as well as ruling out African swine fever and classical swine fever [8] as a cause of the sudden deaths.
• All livestock can be affected by salt toxicity if fresh water is unavailable for more than 24 hours. Pigs may also refuse water if it becomes too hot when delivered by water pipes exposed to the sun. Signs of salt toxicity include excessive thirst, diarrhoea, neurological signs, rapid loss of condition, often progressing to coma and death.
• When water supplies have been interrupted, stock should be slowly re-introduced to fresh water in small, frequent amounts until rehydrated.
• Read more on preventing salt toxicity in livestock [9] and salt poisoning or water deprivation in pigs [10].

Avian influenza and Newcastle disease ruled out in chickens with breathing difficulties

• Avian influenza is an infectious disease of birds caused by an influenza virus. There are many different strains of avian influenza [11]; some strains may cause significant losses if commercial poultry enterprises become infected, and some have the potential to affect human health.
• Newcastle disease [12] is a severe viral disease of poultry and other birds. In the commercial layer and broiler industries, use of risk-based vaccination reduces the risk of exotic or Australian-origin virulent Newcastle disease virus.
• In this case a producer reported a higher than normal mortality rate in their broiler flock. Some of the birds were gasping and lethargic.
• As these signs are similar to the reportable diseases avian influenza and Newcastle disease, the DPIRD laboratory carried out priority testing. The tests were negative for both diseases.
• Further testing confirmed a fungus, Aspergillus fumigatus, in the lungs of five birds.
• Aspergillosis can occur when fungal spores contaminate feed, litter or soil and are then inhaled by poultry. Typical signs include gasping and death rates of up to 50%, most often in younger birds. A chronic form can also develop, more often seen in older birds.
• It is critical that all poultry owners maintain good biosecurity to prevent disease entering their flocks. For more information, see the DPIRD poultry biosecurity checklist [13].
• Any signs similar to avian influenza or Newcastle disease in birds must be reported to your private vet, a DPIRD vet [14] or the Emergency Animal Disease Hotline on 1800 675 888. Learn more about the disease signs in the DPIRD avian influenza [11] and Newcastle disease [12] webpages.

In autumn, be on the lookout for:

Stepping up surveillance skills for animal disease threats across northern Australia

[20]

More than 30 vets from northern Western Australia, the Northern Territory and Queensland stepped up for a veterinary masterclass held in Broome in early March. The focus of the masterclass was to strengthen Australia’s preparedness to recognise and respond to disease outbreaks, particularly African swine fever. Photo credit: Pauline Brightling

Our northern animal health surveillance systems are currently focused on the threat of African swine fever entering Australia, particularly as the virulent pig disease has now spread to our close neighbours Papua New Guinea, Timor-Leste and Indonesia.

Managing animal health surveillance across northern Australia is a herculean task that involves the collaboration and coordination of Commonwealth Government, Western Australian, Northern Territory and Queensland agencies and relies on the active involvement of private and government vets.

The Department of Primary Industries and Regional Development recently facilitated an animal health surveillance masterclass for northern Australian veterinarians to strengthen Australia’s preparedness to recognise and respond to disease outbreaks, particularly African swine fever.

The masterclass, held in Broome from 6-7 March, attracted more than 30 vets from northern Western Australia, the Northern Territory and Queensland, including each jurisdiction’s chief veterinary officer.

Recent international travel and border closures may have lessened some of the potential for the spread of African swine fever to Australia, but there is an ongoing threat from incoming mail containing illegally imported pork and illegally imported pork already present in the country that may contain the virus.

The masterclass took vets through the latest information on African swine fever and the sampling and post-mortem techniques needed to diagnose the disease. Participating vets were provided with a step-by-step guide to conducting a pig post-mortem [21] and were also challenged by a hypothetical disease outbreak and asked how best to investigate and analyse it.

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Participants in recent masterclass for northern Australian vets held in Broome practised applying their investigative skills to a hypothetical disease outbreak. Pictured standing are DPIRD vet and co-organiser Andrew Larkins and WA Chief Veterinary Officer Michelle Rodan. Photo credit: Pauline Brightling

A range of other topics relating to disease investigation and surveillance were also covered in the masterclass.

Key presentations focused on current issues in the neighbouring Asia-Pacific region, investigating reproductive disease in northern Australia and the vital role that vets play in certifying that our stock are free from specific diseases.

It is this ability to demonstrate that we are free from priority diseases and can detect them quickly if they occur that underpins Australia’s reputation for excellent biosecurity and our access to global markets.  

Broome private vet Dave Morrell said the masterclass was a great opportunity to get vets from all over northern Australia in one place and to learn more about animal health surveillance in the region.

“Bringing northern vets together to engage with a common purpose and approach to the threat of disease introductions into northern Australia via this workshop has made a substantial contribution to the delivery of biosecurity and surveillance across northern Australia,” Dr Morrell said.

“The vets particularly benefited from the epidemiological session, which provided investigative and analytical approaches that many of us were not familiar with. These approaches will be vital in the event of a serious animal disease outbreak in northern Australia.”

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Participants in a masterclass to increase preparedness for emergency animal diseases in northern Australia - Broome, March 2020. Photo credit: Pauline Brightling

The Northern Australia Biosecurity Surveillance (NABS) Framework was established by the Commonwealth Government in 2016 to ensure effective and sustainable surveillance systems for priority plant and animal diseases. The Masterclass was coordinated by DPIRD in Western Australia and funded by Commonwealth, State and Territory Governments.

More information about African swine fever is available at agric.wa.gov.au/asf [7]. 

WA Livestock Disease Outlook highlights benefits of surveillance

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 affect trade.

The WA livestock disease outlook – for producers summarises recent significant disease investigations by Department of Primary Industries and Regional Development vets and private vets. Data from these investigations provides evidence that WA is free from these diseases and supports our continuing access to markets.

For more information, see:

• WA's animal health surveillance programs [24]
• subsidies available to support disease investigations [25]
• or contact your local DPIRD vet [14].

Feedback

We welcome feedback. To provide comments, email waldo@dpird.wa.gov.au [26].

To subscribe

To subscribe, go to the WA Livestock Disease Outlook webpage [27] or email waldo@dpird.wa.gov.au [26].