Deadly virus attacks WA dolphin population

A virus that last struck the Perth region 10 years ago has returned
A virus that last struck the Perth region 10 years ago has returned

A DEADLY virus has claimed the lives of five WA dolphins, with experts concerned the numbers could rise.

Tests conducted by Murdoch University researchers have confirmed the presence of Cetacean Morbillivirus, a ‘nasty’ yet naturally occurring virus.

Four of the deceased dolphins were coastal Indo-Pacific bottlenose dolphins, including two known Swan River residents.

Murdoch University veterinary anatomic pathologist Dr Nahiid Stephens said she knew something was ‘fishy’ when a striped dolphin (offshore species) was found in the Swan River.

Four of the deceased dolphins were coastal Indo-Pacific bottlenose dolphins, including two known Swan River residents.

“It is very unusual for this species to be found in the river, in fact it is the first time we know this species has been sighted within the river, he was well off course,’’ she said.

Dr Stephens said the last outbreak of Cetacean Morbillivirus occurred in Perth in 2009, possibly providing some protection to the current dolphin population in Perth.

“It is likely some dolphins who may have been exposed to the virus back in 2009 developed a level of immunity, however it is impossible to know if they are still protected, as this immunity wanes over the years,’’ she said.

While the exact cause of the virus is unknown, there is reason to believe the dolphins caught the virus from a population of pilot whales off the coast of WA.

“Like humans the virus is then spread through touch or aerosol droplets as the whales breathe out,’’ Dr Stephens said.

A virus that last struck the Perth region 10 years ago has returned.

 

Department of Biodiversity, Conservation and Attractions (DBCA) principal scientist Kerry Trayler said the eight adult female resident dolphins living in the Swan and Canning rivers, were critical in keeping this sub population of dolphins alive.

“The virus is the most significant cause of cetacean sickness and death globally with regular occurrences documented in the Mediterranean Sea and Atlantic Ocean,” Dr Trayler said.

“It spreads via infected particles breathed out of the dolphin’s blowhole, and once transmitted, the virus suppresses the animal’s immune system and damages the lungs and brain.

“Humans are not at risk from the virus, which cannot survive outside of a cetacean host.

Dolphins with the virus may exhibit abnormal circling, an inability to swim, seizures and strong but uncoordinated movements.

“There’s still a lot we don’t know about the virus so we’re asking the public to report sightings of dolphins swimming erratically or in circles, or having difficulty breathing, or with skin and oral sores,” Dr Trayler said.

The public are urged to report all unusual dolphin behaviour or sighting to the Wildcare Helpline on 9474 9055.