New Technique for Malaria Diagnosis

Photo: Mosquito

Mosquitos can be vectors of
the malaria pathogen; © SXC

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.

High-power microscopy is still the best method available for malaria diagnosis and has been used for more than a century. Unfortunately it is time-consuming and requires expensive equipment and specialist medical skills, which are rarely available in villages in rural areas in malaria endemic countries. Over the last decade RDTs have been developed, which allow for faster diagnosis in the field, but these are too costly to be viable for developing countries.

Professor Dave Newman of the University of Exeter’ s School of Engineering, Computing and Mathematics, said: „There is an urgent need for a new diagnostic technique for malaria, particularly in the light of global warming, which threatens to spread the disease into new parts of the world, including southern Europe. We expect to ultimately produce a sensitive non-invasive device that will be cost effective and easy to use, making it suitable for developing countries, where the need is greatest.“; Source: University of Exeter