Researchers link new human pathogen linked to fatal encephalitis
Dr Krispin Hajkowicz
RBWH researchers have linked a fatal case of encephalitis with Trubanaman virus – likely the first time this Australian mosquito borne virus has been associated with human disease.
The case involved a Queensland man in his 50s who had recently undergone a bone marrow transplant for leukemia. Less than three weeks later, he developed a fever and confusion.
RBWH Infectious Diseases Physician Dr Krispin Hajkowicz explains how the team managed the patient’s deterioration.
“When all the standard tests came back negative, we knew we were dealing with something unusual,” Dr Hajkowicz said.
“We ran MRI scans, EEGs, cultures, and every viral and bacterial panel available. Nothing explained the cause of his encephalitis.”
With no diagnosis emerging, the clinical team turned to metatranscriptomic sequencing, a next‑generation technique that reads all RNA in a sample.
“That’s when we saw it,” Dr Hajkowicz said.
“Fragments of the Trubanaman virus RNA in the cerebrospinal fluid. It wasn’t a lot, but it was enough to tell us we were looking at a virus that had slipped completely under the radar.
“Given the patient’s profound immunosuppression and the absence of any alternative diagnosis, the most plausible explanation is that Trubanaman virus caused his fatal encephalitis.
“It’s a sobering reminder of how vulnerable immunocompromised patients can be to infections we don’t have a lot of information on. We are incredibly grateful to this family for agreeing to participate in our research.”
Dr Hajkowicz said the case highlights how new diagnostic tools are reshaping infectious disease practice in Australia.
“Metagenomic sequencing is changing the game,” he said.
“We’re now uncovering viruses that have probably been circulating quietly for decades. These tools are revealing pathogens we simply couldn’t detect before.”
Orthobunyaviruses – the family that includes Trubanaman – are known internationally for causing fever and occasionally, encephalitis. However, human diseases linked to Australian members of this group are not well understood.
“This case tells us we need further research into where this virus is found, what mosquitoes spread it and who is at risk,” Dr Hajkowicz said.
“The findings from this case should prompt a broader shift in thinking about research and treatments.
“As clinicians, we need to keep mosquito borne viruses in mind when faced with unexplained neurological disease, especially in patients with weakened immune systems.”