Smartphone Microscope Diagnoses Parasitic Worm Infection

Thomas B. Nutman, NIAID

We may praise them for keeping us entertained on long journeys or landing us with a date, but many of us probably take for granted the remarkable capabilities of smartphones.

While we’re uploading pouty selfies onto Instagram, scientists are busy trying to find ways to turn these devices into portable HIV testing kits, Parkinson’s disease monitors and heart attack warning systems, for example. In the future, they could even help sniff out early signs of life-threatening diseases on your breath. Now, scientists have developed another amazing use for them: diagnosing infection with parasitic worms.

Named “CellScope Loa,” UC Berkeley’s innovative smartphone microscope is an upgrade of their first generation invention, CellScope, which exploits the camera of cell phones to gather close up images for a variety of medical, scientific and educational purposes. The difference is that their upgrade uses video, rather than images, to automatically detect and quantify parasitic worm infections in blood samples.

This may sound like a minor improvement, but it is actually significant. The ability to magnify samples for examination in the field is great, but many samples need to be prepared in certain ways in order to get any meaningful information, such as staining them or adding in molecular tags. Since these gadgets are designed for use in remote places that might not have these capabilities, usefulness is immediately limited. CellScope Loa, on the other hand, uses video to detect worms wriggling around in drops of blood, without the need to treat samples in any special way.

The worm this new gadget was designed to scout out is a parasite called Loa loa, the causative agent of loiasis. The pathogen, which is found throughout West and Central Africa, is transmitted to humans via bites from infected deer flies. For most people, infection is symptomless and goes unnoticed. So why is it a big deal?

Unfortunately, Loa loa has hindered public health efforts to reduce the burden of two other diseases, river blindness and elephantiasis, which are also both caused by parasitic worms. But these two diseases are much more severe than loiasis. River blindness, obviously, can cause individuals to lose their vision, and elephantiasis can result in a disfiguring disease that can lead to temporary or permanent disability. The reason that loiasis is standing in the way of public health campaigns is because the drug used to treat the two aforementioned infections, ivermectin (IVM), causes potentially fatal side effects in patients co-infected with Loa loa, such as severe brain damage.

Although diagnosing Loa loa does not necessitate sophisticated lab equipment, it does require trained technicians and lab microscopes, which are things that many remote places affected by the worm are not blessed with. Furthermore, the process can be lengthy, which is not ideal for mass IVM campaigns. But these issues could soon be negated, thanks to CellScope Loa.

After placing a drop of blood on the device, which the phone slots into, all healthcare workers need to do is run a specially designed app that uses an algorithm to automatically analyze any squirming worms in the sample. Results are then displayed on the phone screen in a matter of minutes, allowing the rapid administration of IVM for those without the worm.

Although it has only been tested on 33 patients in Cameroon so far, the results were promising. As described in Science Translational Medicine, it picked up 100% of positive cases and gave only a very small number of false negative results. Trials are now being expanded to a further 40,000 individuals.

 

 

[Via Science Translational Medicine, Science and UC Berkeley]

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