Diagnostic Tests Could Accelerate Identification of Hidden Plasmodium Parasites

A macro image of a mosquito. Courtesy of WEHI

Research to develop and deploy a world-first diagnostic test that could accelerate malaria eradication has been bolstered with more than $1.3 million in new funding from the National Health and Medical Research Council (NHMRC).

Two WEHI projects have received funding to clinically translate a test that can detect people with ‘hidden’ Plasmodium vivax (PV) – considered the most widespread and resilient malaria parasite for its ability to remain dormant in the liver for years.

The funding will support the development of the first point-of-care rapid diagnostic test and the deployment of the laboratory version of the test in the Philippines.

Malaria is caused by Plasmodium parasites, which are transmitted to humans through the bite of an infected mosquito. There are more than 200 million cases of malaria worldwide each year, and around 620,000 deaths.

The Plasmodium vivax parasite is particularly challenging because it can be carried in a dormant state in the liver for years, only to later reawaken and continue spreading disease.

Professor Ivo Mueller, a world expert in the biology, epidemiology and control of P. vivax malaria, worked on crucial research that led to the first test to accurately pinpoint when someone has been infected with the parasite and importantly, whether they are at risk of relapsing. His team will now work to develop a rapid point-of-care diagnostic test based on this research, in a continuing collaboration with Australian biotech companies Axxin and ZiP Diagnostics.

Mueller,  who serves as joint division head of WEHI’s Population Health and Immunity Division, said the test would be a game-changer for malaria control programs that have been trying to stamp out this relapsing parasite for decades. “Being able 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,” he said. “Our novel test can show whether someone has had a P. vivax infection within the last nine months. This timing is critical as most people in tropical regions are expected to relapse within nine months of a previous blood-stage infection. Malaria reinfections are a leading cause of residual transmission that continue to challenge malaria eradication efforts. Our test is the closest the scientific world has come to tracking and predicting these ‘hidden’ infections and we are thrilled to start translating these findings to a rapid diagnostic test to improve the lives of those affected by the malarial health burden.”

Mueller is conducting this work with WEHI researcher, Dr. Rhea Longley, who will deploy a high-throughput, laboratory version of the diagnostic test in the Philippines. Both researchers are members of WEHI’s Centre for Global Disease and Health.

Leveraging the expertise of teams in the U.S. and Philippines, researchers will implement a multi-disciplinary approach to focus their efforts in the Sultan Kudarat province that has seen recent P. vivax outbreaks.