Smartphone microscope detects parasites in blood

Researchers have developed a new smartphone microscope that uses video to detect and quantify infection by parasitic worms in a drop of blood within minutes.

The University of California, Berkeley developed the technology, called CellScope, which could help eradicate debilitating filarial diseases in Africa by providing critical information to healthcare providers in the field.

“We previously showed that mobile phones can be used for microscopy, but this is the first device that combines the imaging technology with hardware and software automation to create a complete diagnostic solution,” said Daniel Fletcher, an associate chair and professor of bioengineering, whose UC Berkeley lab pioneered the CellScope.

“The video CellScope provides accurate, fast results that enable health workers to make potentially life-saving treatment decisions in the field,” he said.

The UC Berkeley engineers teamed up with Dr Thomas Nutman from the National Institute of Allergy and Infectious Diseases (NIAID), and collaborators from Cameroon and France to develop the device.

They conducted a pilot study in Cameroon, where health officials have been battling the parasitic worm diseases onchocerciasis (river blindness) and lymphatic filariasis.

River blindness is transmitted through the bite of blackflies and is the second-leading cause of infectious blindness worldwide.

Lymphatic filariasis, spread by mosquitoes, leads to elephantiasis, a condition marked by painful, disfiguring swelling. It is the second-leading cause of disability worldwide and, like river blindness, is highly endemic in certain regions in Africa.

The video CellScope, which uses motion instead of molecular markers or fluorescent stains to detect the movement of worms, was as accurate as conventional screening methods, the researchers found.

For the latest generation of the mobile phone microscope, named CellScope Loa, the researchers paired a smartphone with a 3D-printed plastic base where the sample of blood is positioned.

The base included LED lights, microcontrollers, gears, circuitry and a USB port.

Control of the device is automated through an app the researchers developed for this purpose.

With a single touch of the screen by the healthcare worker, the phone communicates wirelessly via Bluetooth to controllers in the base to process and analyse the sample of blood.

Gears move the sample in front of the camera, and an algorithm automatically analyses the telltale ‘wriggling’ motion of the worms in video captured by the phone. The worm count is then displayed on the screen.

The procedure takes about two minutes or less, starting from the time the sample is inserted to the display of the results. Pricking a finger and loading the blood onto the capillary adds another minute to the time.


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