RAT test for ‘hidden’ malaria one step closer to development

A simple ‘RAT test’ for hidden malaria developed by Australian scientists might be a true game changer for countries affected by the parasite.

The National Health and Medical Research Council (NHMRC) has awarded two private companies working with the Walter and Eliza Hall Institute $1.3m, to push the proof-of-concept prototype into a product that could be used in clinical trials.

The researchers have created a blood test that can be done with a simple finger prick, and the team is seeing if saliva could also be used. This test looks for eight antibodies that respond to Plasmodium vivax proteins and was found to be 80% accurate in research papers.

The parasite Plasmodium vivax causes the deadliest type of malaria, and is found in Asia, Latin America, and in some parts of Africa. Like all malaria, the parasite is spread to humans through the bites of infected mosquitoes.

In 2020, WHO estimated there was 241 million cases of malaria worldwide and 627,000 deaths.

“This is an entirely novel diagnostic approach – in terms of biomarkers used, test technology and application,” Professor Ivo Mueller, a WEHI malaria researcher told Cosmos Science.

“Developing these concepts and technology as well as the scientific evidence supporting its feasibility took quite a few years.

“This was not an obvious path to take and required significant innovation.”

With the NHMRC grant money, the team will be able to work with Australian biotech companies Axxin and ZiP to develop the test towards a scalable product.

“We are working on both a high throughput assay for reference laboratories at WEHI and on the point-of-contact (POC) test with Axxin and Zip,” says Mueller.

Testing for hidden malaria

Some people with malaria end up with a ‘hidden’ infection – either after having malaria symptoms or being completely asymptomatic.

Those with the hidden infection still have dormant ‘hypnozoites’ in the liver that can cause a relapse in infection and be transmitted via mosquitos.

“Being able to directly target hidden liver-stage parasites is crucial for successful vivax elimination because they can be responsible for over 80 per cent of all blood-stage infections. Unfortunately, there are currently no tests that can accurately detect who is carrying this insidious parasite in their bodies,” says Mueller.

Read more: What Timor-Leste’s and West Timor’s differing approaches to malaria can tell us

The team hopes the combination of testing for the antibodies and treating (called PvSeroTAT) would allow those with hypnozoites to be quickly treated and lower the case numbers of malaria in any given area.

A modelling study in Brazil found that PvSeroTAT could lower the prevalence of malaria in an area by up to 25%.

However, the team behind the new discovery has not been able to secure finance in Australia for larger clinical trials, which will now go offshore.

“We have really struggled with that in Australia. There are basically no appropriate domestic funding streams for this kind of highly innovative, global health clinical trial. We twice submitted to the NHMRC Clinical Trials and Cohort Study grant scheme, but were not successful,” Mueller told Cosmos Science.

“Interestingly, with colleagues in France and UK, we submitted a grant (application) with the same study designs to the European Union Horizon 2020 program for funding. There the same study received an excellent review and $10 million AUD in funding for two very large cluster randomised trial in Ethiopia and Madagascar.

“Although that trial is based on Australia IP, an Australian diagnostic test and although the PvSeroTAT intervention (as a concept) was also develop by us in Australia, it will be our colleagues in Europe who will be the first ones to conduct a pivotal clinical trial and will thus get a large part of the credit for the work we did here. This is a quite striking example how Australian IP and Innovation is moving overseas because we can’t raise the required funding locally.”