Mobile phone microscope saving lives (and eyes) in Africa

Nature has more on a cell phone gizmo that’s changing how medicine is done in remote places:

In a study in Science Translational Medicine on 6 May, bioengineer Daniel Fletcher of the University of California, Berkeley, and his colleagues give one example of how mobile phones may change medicine in far-flung areas. They describe a camera-phone microscope and app that can immediately detect the presence of the African eye worm parasite Loa loa in a blood sample.

An endemic problem in Central Africa, L. loa grows into a worm that wiggles into the tissue of the eye. The worms are even more problematic when they are picked up along with two other parasitic nematodes, Onchocerca volvulus (which causes river blindness) and Wuchereria bancrofti (which can cause severe limb swelling). This is because one drug typically given to treat those two other parasites, called ivermectin, can cause serious side effects such as brain swelling if a person is also infected with L. loa.

By converting a phone into a microscope, clinicians have a portable way of checking blood samples.

[A]s Samuel Sia, a biomedical engineer at Columbia University in New York, points out, earlier models were not a big improvement over a traditional microscope for use in the field because all they did was magnify. “You’d have to collect a specimen, smear it, stain it and dry it on a slide. Sure, if you have a microscope you can look at it, but what about all those other steps?”

The latest invention by Fletcher and his team, by contrast, avoids that rigmarole — it requires simply loading a blood-containing capillary onto a 3D-printed plastic case containing a lens. The plastic shell slides over an iPhone, aligning the device’s lens to its camera.

An app on the phone then takes a video of the magnified blood sample and uses an algorithm to look for movements in the fluid that match up with characteristics of L. loa. Based on this, the app accurately counts how many parasites are present.