Avian Flu Diary: Australia: Update On Unexplained Horse Deaths (n=13) In Victoria

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Yesterday, in Australia: Agriculture Victoria Investigating Sudden, Unexplained Horse Deaths, we saw reports of 10 unexplained equine deaths across 3 horse farms located on the Mornington Peninsula, south-east Melbourne and southwest Victoria, with no immediately apparent epidemiological links.

While the cause remains unknown, today Agriculture Victoria reports that the numbers have risen to at least 13 horses across 5 properties.

Tests for Anthrax and Hendra virus have reportedly come back negative, and investigations are looking at a variety of other possible causes. Their most recent update follows:

Sudden horse death investigations

Current situation - 17 July 2023

Agriculture Victoria's investigation into multiple sudden horse deaths is continuing.

The investigation is in its early stages and extensive surveillance and testing is explore the possible causes of the illness and death in horses, which have occurred since Tuesday 4 July.

Agriculture Victoria is working with private veterinarians and industry experts, responding to calls and building a bigger picture of the situation.

Horse owners should monitor their animals and report any sudden deaths or rapid onset illness immediately to their local vet, Agriculture Victoria or via the emergency animal disease hotline on 1800 675 888.

Those who are concerned about sick horses should seek advice from their vet. Rapid reporting after death will assist Agriculture Victoria and veterinarians to further investigate the situation.

As at 4pm Monday 17 July 2023, there have been 13 confirmed sudden horse deaths on five separate properties reported to Agriculture Victoria. The reported properties are located on the Mornington Peninsula (one property), south-east Melbourne (two properties near Cranbourne) and near Ballarat and Colac in the west. It is not yet known what has caused these deaths. Some of the cases which have just been reported occurred some weeks ago.

Early testing for a wide variety of infectious diseases, including Hendra and anthrax, has been negative however the investigation remains ongoing. More testing is required, for a range of possible infectious and non-infectious causes.

It is not yet known what has caused these deaths. All horses died quickly with short term non-specific signs of illness and initial assessment has not revealed immediate common links.

Agriculture Victoria has also looked into other reports made to the hotline which are not believed to have any connection at this stage.

As testing of samples for infectious disease to date has been negative, there’s no cause to restrict any movements of horses or separate horses at this stage. Horse events and movements can go ahead as planned.

There have also been several reports on social media channels of further affected properties. Agriculture Victoria is calling on these owners to make contact so they can assist with investigations.

Early testing for some infectious diseases has been negative. More testing is required, however, for a range of possible infectious and non-infectious causes.

Please be mindful of what you share online, and do not share misinformation online or on social media.

Agriculture Victoria also sent out the following Veterinary Alert yesterday.

17 July 2023
Veterinary alert: sudden horse deaths

Agriculture Victoria is working to investigate the cause of multiple sudden deaths in horses which have occurred on separate properties since Tuesday 4 July. To date, there have been ten confirmed horse deaths on three separate properties. The properties are located on the Mornington Peninsula, south-east Melbourne and southwest Victoria, with no common links immediately evident. The affected horses reportedly died quickly with short-term non-specific signs of illness or no observed illness.

The investigation involves owners, private veterinarians, and a range of experts, including the Australian Centre of Disease Preparedness and the University of Melbourne. While the investigation is in early stages, testing for a number of infectious diseases has to date been negative. Potential toxicities are also being explored. Unfortunately, the investigators currently have access to limited suitable diagnostic samples.griculture Victoria website

Several informal reports of further affected properties are being investigated, with a number of instances of false information identified to date. Anyone aware of speculated further cases is asked to encourage official notification. Please do not share unconfirmed information online or on social media.

Agriculture Victoria is asking for notification of any sudden horse deaths in Victoria since 1 July 2023. Notifications can be made via EAD Hotline on 1800 675 888 for new cases or via cvo.victoria@agriculture.vic.gov.au for past cases (since 1 July) that have not yet been reported.

Timely engagement is critical for obtaining good quality diagnostic samples.

Although samples to date have tested negative for Hendra, each call-out should be considered on case-by-case basis and may not be connected to this incident, therefore Hendra precautions should be taken. Practitioners should consider rushed testing for Hendra (facilitated by Agriculture Victoria) in acutely ill or dead horses and prior to any invasive investigations or treatment. When contact is unavoidable, use of full PPE, including impervious boots (for example, gumboots), overalls and gloves, safety eyewear and P2 respirator mask is of critical importance in case of Hendra or other zoonotic diseases.

Horse owners are reminded to make sure their Property Identification Code (PIC) details are up to date. PICs are free and easy to get on the Agriculture Victoria website.