A student-professor team at Case Western Reserve University has invented a hand-held malaria detector that works on an unusual principle: Malaria parasites are stuffed with iron, so their innards can be magnetized.
The team, which has incorporated itself as the Disease Diagnostic Group, is seeking investors to pay for field tests to prove that its device works as well on the African front lines as it does in a Cleveland lab. Its pitch is that its battery-powered box, which costs $250 to make, can undercut the price of current chemical-based rapid test kits by at least 50 cents per test and pay for itself quickly. The company claims its test is far more accurate than the kits at detecting low-level infections.
It has long been known that malaria parasites eat the hemoglobin in red blood cells but cannot digest its iron nor excrete it. Each parasite has a holding tank called a food vacuole filled with iron-rich crystallized hemozoin. A proposal to gently microwave malaria victims to explode the parasites was based on that fact.
The Case Western device dilutes a drop of blood with water, places a magnetic field around it and shines a laser through it. If the blood has parasites, the water splits them and the needle-shaped hemozoin crystals line up in the magnetic field, partly blocking the laser.
In tests on stored blood samples from Papua New Guinea, said Brian T. Grimberg, a Case Western biologist, the magnet-laser box was almost twice as accurate as a microscope technician at finding parasites, and more than three times as accurate as the kits.
The rapid kits, introduced in the last decade, have sped up malaria diagnoses in rural clinics, but they cost at least $1 each and expire in hot climates, Dr. Grimberg added.
His device failed to win grant support from the Bill & Melinda Gates Foundation, Dr. Grimberg said, but that was before the recent blood tests. A foundation spokeswoman said that she did not know why any single one of thousands of applications was denied, but that the foundation was interested in iron-based malaria detection.