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19-03-2013 | Gastroenterology | Article

Mobile phone microscope shows promise in detecting helminth infections


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medwireNews: A microscope made from a mobile telephone, a glass lens costing less than US$ 10 (€ 8), double-sided tape, and a flashlight can successfully detect intestinal infection with soil-transmitted helminths in Tanzanian children, report scientists.

Lead author Isaac Bogoch, from Toronto General Hospital in Ontario, Canada, commented in a press statement: "We think cell phone microscopes could soon become a valuable diagnostic tool in poor, remote regions where intestinal worms are a serious health problem, particularly in children."

He continued: "I'm confident that in the near future we will see cell phone microscopes widely used in low-resource settings… They're easy to make, portable, and today, you can find mobile phones with cameras even in some of the most remote regions in the world."

For the study, morning stool samples were collected from children over a 5-day period and processed using the Kato-Katz technique.

For the mobile phone microscope, a 3-mm ball lens was mounted onto the camera of an iPhone 4S, with double-sided tape used to position the lens. The Kato-Katz thick smear slides were placed against the tape, and illuminated below using the flashlight.

In all, 199 smear slides were examined using both mobile phone and conventional light microscopy.

The team found that the mobile phone microscope has a sensitivity and specificity of 69.4% and 61.5%, respectively, for detecting any soil-transmitted helminth infection.

The highest diagnostic yield in terms of sensitivity was for Ascaris lumbricoides and Trichuris trichiura, at 81.0% and 54.4%, respectively. The sensitivity for detecting hookworm was just 14.3%. Sensitivities with the mobile phone microscope were higher for heavy-infection intensity slides than for those with lower fecal egg counts, and it was notable that all hookworm infections were of low intensity, at <2000 eggs per 1 g stool.

The 26 slides with no visualized helminth eggs on conventional microscopy were found to have 61.5% concordance on mobile phone microscopy.

The team writes in the American Journal of Tropical Medicine and Hygiene: "From a practical standpoint, the sensitivity for diagnosing any soil-transmitted helminth egg with the mobile phone microscope was close to 70%, and although it is not sensitive enough for immediate application, it is getting close to acceptable diagnostic characteristics."

By Liam Davenport, medwireNews Reporter

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