Malaria detection using breath biomarkers

Although there were almost 200 million cases of malaria in 2013, resulting in over half a million deaths, this lethal infection is in retreat.1 Better control through prevention with insecticide-treated nets and more effective drugs (including artemisinin, for the discovery of which the 2015 Nobel Prize in Physiology or Medicine was awarded) mean that the ambition of elimination is again on the agenda. Sensitive diagnosis of malaria is becoming increasingly important, particularly for low-level and asymptomatic cases. Currently, most diagnoses of malaria use microscopy, which is not sufficiently sensitive to enable elimination and is dependent on highly trained operators with good equipment.

In a collaboration between the CSIRO and QIMR Berghofer Medical Research Institute, we tested the breath of volunteers who had been given a controlled Plasmodium falciparum malaria infection in a clinical trial of new drug treatments. The levels of four sulfur compounds in the breath of the volunteers consistently rose and fell with the life cycle of the parasite and cleared with the recovery process.2

It was particularly exciting that elevation of the levels of the sulfur compounds could be detected at the earliest stages of infection, when blood-smear microscopy is unable to detect the malaria infection. This finding suggests that the biomarkers could be exploited in a simple diagnostic test with better sensitivity than blood smears or rapid immunodiagnostic tests.3 In addition to its potentially great sensitivity, the non-invasive nature of breath sampling could be advantageous for on-the-spot diagnosis in resource-limited settings.

The CSIRO and QIMR Berghofer teams are expanding their collaboration to investigate whether the same changes in breath composition are reliably detected in patients in malaria-endemic areas. If so, this will open the way to developing a robust portable sensing device, specific for the four sulfur compounds, that could be used in the field to test for malaria infection.