Exeter engineers create new technique for malaria diagnosis

Researchers from the Universities of Exeter and Coventry have developed the first new technique for diagnosing malaria able to challenge the rapid diagnostic tests (RDTs) currently used in the field. Early results, now published in the Biophysical Journal, suggest that the technique could be as effective as RDTs but far faster and cheaper, making it a potentially viable alternative. The team is now working on a non-invasive version of the device, which with the assistance of a team from the Royal Tropical Institute (KIT), Department of Biomedical Research in Amsterdam, it is planning to trial in Kenya later this year.

Two years in the making and funded by the European Union, this technique uses magneto-optic technology (MOT) to detect haemozoin, a waste product of the malarial parasite, in the blood. Haemozoin crystals are weakly magnetic and have a distinct rectangular form. They also exhibit optical dichroism, which means that they absorb light more strongly along their length than across their width. When aligned by a magnetic field they behave like a weak Polaroid© sheet such as used in sunglasses. This new technology takes advantage of these properties to give a precise reading of the presence of haemozoin in a small blood sample. The team has created a device, which gives a positive or negative reading for malaria in less than a minute.

The new device has a totally different approach from RDTs, which use a chemical agent to detect antigens associated with the malarial parasite. One of the problems with RDTs is that they need to be kept within a given temperature range, which is difficult in hot climates. These disposable kits cost between $1.50 and $4.50 each and take around 15 minutes to deliver a reading.