A narrated video explaining the steps involved in screening a blood sample for the Loa loa parasitic worm. (Video by Mike D’Ambrosio and Matt Bakalar, Fletcher Lab, UC Berkeley) UCB

A smartphone microscope that detects and quantifies parasites in a drop of blood has been developed by researchers led by UC Berkeley.

A pilot study in Cameroon, ravaged by river blindness and lymphatic filariasis, was as accurate as conventional screening methods, the researchers found.

The mobile phone microscope CellScope uses motion instead of molecular markers or fluorescent stains to detect the movement of worms.

The results of the study are reported in the journal Science Translational Medicine.

CellScope pairs a smartphone with a 3D-printed plastic base for the blood sample, LED lights, microcontrollers, gears, circuitry and a USB port.

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. The procedure takes about two minutes or less.

This next generation technology is expected to help revive efforts to eradicate debilitating diseases in Africa.

"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 antiparasitic drug ivermectin, or IVM, used to treat these diseases has potentially fatal side effects for patients co-infected with Loa loa, which causes loiasis, or African eye worm.

The standard method of screening for levels of Loa loa involves trained technicians manually counting the worms in a blood smear using lab microscopes, ruling out efficiency for mass campaigns.

CellScope offers a way out by quickly counting the numbers of Loa loa parasites in a drop of blood.

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

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 and swelling. It is the second-leading cause of disability worldwide.