Mobile phone microscope detects worm infections

Copyright: Flickr/USArmyAfrica

Speed read

  • The microscope is US$185 cheaper than current technology
  • Mobile phone zoom enables slides to be magnified up to 60 times
  • Scientists hope to increase accuracy from 70 to 90 per cent needed for clinical rollout

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[KAMPALA] Children suffering from intestinal worms can now be diagnosed using a mobile phone microscope that is significantly cheaper than conventional methods, which are prohibitively expensive for many communities

The microscope costs around US$15 and runs off the phone's battery, whereas a conventional light microscope costs US$200 and requires electricity in most countries.

To build the microscope, scientists transformed an iPhone 4S mobile phone into a microscope by temporarily mounting a 3-millimetre ball lens to the camera, using double-sided tape to hold it firmly. A US$8 ball lens was positioned in a small hole punctured in the middle of the double-sided tape.

They then placed the mobile phone microscope on top of the slide, which was illuminated from below by a small flashlight. Images were viewed on the mobile phone screen, and magnification of up to 60 times was enabled using the digital zoom function.

Scientists from Canada, Switzerland, Tanzania and United States, used the microscope to evaluate stool samples from almost 200 children in Pemba, Tanzania, alongside conventional light microscope to measure the efficacy of different intestinal worm treatments.

A study published yesterday (11 March) in the American Journal of Tropical Medicine and Hygiene reports that the accuracy of the mobile phone microscope varies depending on the worm type and infection intensity. The microscope was found to detect 69.4 per cent of helminth eggs, 81 per cent of giant roundworm infections and 14 per cent of all hookworm infections.

"It is 70 per cent accurate but we think it can be up to 90 per cent," says Isaac Bogoch, an infectious disease specialist at Toronto General Hospital, Canada, and the study's lead author. The study reports that the microscope will only be of clinical standard when it is sensitive enough to detect 80 per cent of infections.

"It was quite successful at detecting moderate to heavy infections but not very good at detecting mild infections where there might be only a few eggs in the sample," Bogoch adds.

However, the researchers are confident the technology could be a valuable and popular tool for regions where intestinal worm infestation is widespread, due to it being easy to make, portable and cheap.

The new application is also potentially relevant in the diagnosis of other infections in the blood, urine and intestine, says Bogoch, and could work equally well with other types of phones with camera zooms.

David Walker, president of the American Society of Tropical Medicine and Hygiene, says: "This study is an illustration of how a modest investment in tropical disease research can help reap enormous health benefits for children."

Jennifer Atim, a data specialist at Health Alert-Uganda, says the innovation is another tool for improving child health, but wonders whether it will be available since many information and communication technology related innovations fail to make the transition from lab to field in Africa.

Intestinal worms can hinder physical and mental development in children by causing chronic anaemia and malnutrition, but when diagnosed early can be treated successfully with cheap drugs

Link to full study

This article has been produced by SciDev.Net's Sub-Saharan Africa desk.



American Journal of Tropical Medicine and Hygiene doi:10.4269/ajtmh.12-0742 (2013)