With just one test, all strains of the deadly – humanly harmless – Infectious spleen and kidney necrosis virus (ISKNV) that threaten fisheries and aquaculture can now be detected.

Researchers from the Universities of Florida and Sydney, Australia have developed a new genetic test for the fish-killing infectious spleen and kidney necrosis virus (ISKNV), which affects ornamental and farmed fish species all over the planet.

ISKNV is known to have three different types, but tests that have been proven to identify the virus only pick up two of these types.

Today, new research was published in the journal PLOS One. It shows that a single test can detect all three genomic variants of the virus, which can kill 50–100% of infected fish.

In barramundi farms in Southeast Asia, the third variety, known as TRBIV, is an emerging infection that is killing fish. Although TRBIV-related sickness must be reported to the World Organisation for Animal Health (WOAH), testing for TRBIV is not mandated by WOAH.

Associate Professor Joy Becker from the University of Sydney’s School of Life and Environmental Sciences is one of the paper’s corresponding authors. 

According to her, “the emerging TRBIV variant is a risk to the Australian barramundi industry.

“Our new diagnostic test is the most advanced in addressing WOAH requirements for test validation. It can detect all three variants of the virus with very high sensitivity and specificity.

“Once validated, we expect this diagnostic test will help keep this exotic virus out of Australia.”

According to the Australian Department of Agriculture, although ISKNV has not been discovered in wild fish populations in Australia, it is often detected in ornamental fish in quarantine at the international border and in retail pet stores.

“Exotic disease incursions are one of the biggest risks for our wild and farmed fish,” warns Associate Professor Becker. 

“The ISKN virus, which now includes the TRBIV variant, is a risk to Australian species, including barramundi and Murray cod.

“Our diagnostic test is designed to detect all three variants and provides the stringency we need to uphold Australia’s world-class biosecurity.”

Associate Professor Becker claimed that although the virus is fatal to infected fish, it offers no threat to people.

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