New test fasttracks diagnosis for malaria

A new test can cheaply and accurately diagnose a malaria infection in just a few minutes using only a droplet of blood, researchers reported Sunday in the journal Nature Medicine. The tool could replace the laborious, error-prone method in which a lab technician looks for malaria parasites in a blood sample through a microscope, they said. While that method is considered the gold standard in malaria diagnostics today, its reliability depends on the technician's skill in interpreting the image, the quality of the microscope and lab chemicals and even on the thickness of the blood smear on the slide itself. The touted replacement is an "inexpensive" desktop mini-lab that, according to its inventors, can detect fewer than 10 malaria parasites per microliter of blood, using a sample of less than 10 microliters - equivalent to a small drop from a finger prick. The whole procedure just takes a few minutes, the inventors said.

While malaria is both preventable and treatable, it has killed an estimated 627,000 people in 2012, mainly children in Africa, according to the World Health Organization (WHO). That year there was also an estimated 207 million cases worldwide, and the WHO says current funding levels are "far below" what is needed to eradicate the disease. The device unveiled in Nature Medicine uses magnetic resonance relaxometry (MRR), a cousin of magnetic resonance imaging (MRI), the technology that powers today's advanced medical scanners. It measures the crystals metabolized by the Plasmodium parasite that causes the disease. After the creature - which is transmitted to humans via mosquito bites - feasts on nutrient-rich haemoglobin in the blood. These waste-product crystals (hemozoin) contain a minute amount of iron, making them slightly magnetic. The presence of the tiny particles disrupts the synchronous spin, or resonance, in hydrogen atoms that are exposed to a magnetic field. The more particles there are, the faster this "synchrony" is disrupted. That means the test can not only tell when someone has been infected, it can also see whether treatment is working, as shown by a fall in the number of parasites in a patient's blood..