One of the Clydesdales that pull the horse-drawn tram over the Granite Island causeway has died.

The horse, Isabella, was euthanised on Monday 15 April following complications associated with Ross River Virus.

Seven of the other eight horses in the Clydesdale team have also tested positive to the virus in the past four months.

The popular tourist attraction is run by the Victor Harbor Horse Tram Authority, a subsidiary of the City of Victor Harbor.

Its team of Clydesdales pull the tram that carries passengers across the causeway to Granite Island, usually operating several services every day except Christmas day.

In a statement the council says the tram team is devasted at the loss of the much-loved horse.

“Ross River Virus is a mosquito-borne illness that is common in many regions across Australia. It can cause similar symptoms in horses as it does humans. 

“Isabella had tested positive for the virus several weeks ago, initially experiencing a high temperature. Over time, she also suffered loss of appetite and neurological decline. 

“In line with advice from vets as symptoms worsened, Isabella was transported to Mt Torrens where she was able to receive specialised, intensive veterinary care for the past three weeks. 

“Unfortunately, a continuing decline in her health and the discovery of colic lead to the difficult veterinary decision to euthanise Isabella and put an end to her pain.”

The council says the other horses are improving in condition and expected to make a full recovery.

“While recovering from the virus, these horses have not been operating the Horse Tram.”

The tram has been operating on a reduced timetable while the horses have been ill and this will continue as they recover. Visit the tramway Facebook page for more information.