Colour test to diagnose three day sickness on-farm under development

DAF scientist Dr Beth Fowler was a speaker at the Brian Pastures Field Day where she presented the portable tools they had developed, which would allow producers, vets or government officers to detect pathogens and disease in livestock.

She said the prototype tests they had worked on were for three day sickness, the causative agent being bovine ephemeral fever virus.

Three types of tests had been developed to detect the virus; colour, fluorescent and a dipstick test, which were all designed to detect pathogens.

The colour test had been identified as the most simple of the three tests.

"It has a simple yes/no output...you need accompanying hardware that comes with the tests and requires some sort of power to operate," she said.

"In a field you would collect a sample, blood or tissue from an animal that is showing signs of three day sickness, process it to isolate the DNA, add the test to the colour solution tube, heat it up to 65 degrees for 15 to 30 minutes, then look for colour change.

"If the sample has three day RNA in it, it will change colour from pink to yellow the animal is positive, if something else is making the animal sick, it will stay pink.

"The PCR machine does the heating, it can heat two strips of eight tubes, so 16 reactions....it costs about $1500 to purchase.

"That's cheap, to buy something like that for a lab is about $20,000 or $30,000...it could also run PCR tests and is operated through a phone via an app."

A portable reader is also being developed that will ensure accurate reading of results, with a light source to illuminate the test tubes, and a camera that takes images, which are sent to a microcomputer that uses AI algorithms to determine results.

Dr Fowler said they picked three day sickness as a proof of concept disease for the research, because it was prevalent throughout Queensland, and a concern to industry.

She said while some producers did not consider three day sickness a significant threat to cattle, she had spoken with other producers who attributed the sickness to the loss of their prize bull.

"One of the benefits of being able to detect the virus in your animal is that it is not there for a very long time, so if you animal is positive you can begin to treat it straight away," she said.

"You can tell your vet what it is and they can determine the treatment regime that you should follow.

"You can isolate the animal and restrict it from passing it on to other animals."

Dr Fowler said they hoped the test could be carried out by producers on-farm.

"We hope to have the test validated by next year and would then seek a commercial partner to produce the test."