Motility-based label-free detection of parasites in bodily fluids using holographic speckle analysis and deep learning

Yibo Zhang,Yilin Luo,Rohan Nadkarni,Zhensong Wei,Sener Yalcin,Michelle M Shimogawa,Aydogan Ozcan,Bohan Zhang,Yi Luo,Kent Hill,Alexander Guziak,Tairan Liu,Hatice Ceylan Koydemir,Vittorio Bianco,Yujia Huang,Hongda Wang,Bijie Bai,Ilker Oguz

doi:10.1038/s41377-018-0110-1

Abstract

Parasitic infections constitute a major global public health issue. Existing screening methods that are based on manual microscopic examination often struggle to provide sufficient volumetric throughput and sensitivity to facilitate early diagnosis. Here, we demonstrate a motility-based label-free computational imaging platform to rapidly detect motile parasites in optically dense bodily fluids by utilizing the locomotion of the parasites as a specific biomarker and endogenous contrast mechanism. Based on this principle, a cost-effective and mobile instrument, which rapidly screens ~3.2 mL of fluid sample in three dimensions, was built to automatically detect and count motile microorganisms using their holographic time-lapse speckle patterns. We demonstrate the capabilities of our platform by detecting trypanosomes, which are motile protozoan parasites, with various species that cause deadly diseases affecting millions of people worldwide. Using a holographic speckle analysis algorithm combined with deep learning-based classification, we demonstrate sensitive and label-free detection of trypanosomes within spiked whole blood and artificial cerebrospinal fluid (CSF) samples, achieving a limit of detection of ten trypanosomes per mL of whole blood (~five-fold better than the current state-of-the-art parasitological method) and three trypanosomes per mL of CSF. We further demonstrate that this platform can be applied to detect other motile parasites by imaging Trichomonas vaginalis, the causative agent of trichomoniasis, which affects 275 million people worldwide. With its cost-effective, portable design and rapid screening time, this unique platform has the potential to be applied for sensitive and timely diagnosis of neglected tropical diseases caused by motile parasites and other parasitic infections in resource-limited regions.

Highlights

Parasitic infections affect billions of people globally and cause a massive socioeconomic burden[1,2,3,4]
The need for development of new methods with high sensitivity and throughput that can reduce costs and simplify diagnosis is urgent. To address this important challenge, we demonstrate a cost-effective and field-portable optical device (Fig. 1), which is based on lensless time-resolved holographic speckle imaging, for label-free, high-throughput, and sensitive detection of motile parasites in various bodily fluids and turbid media
We demonstrated the success of our platform to detect other motile parasites in bodily fluids by imaging Trichomonas vaginalis (T. vaginalis), the protozoan parasite responsible for trichomoniasis, which is the most common, nonviral sexually transmitted disease that affects 3.7 million people in the United States and 275 million worldwide[28]

Summary

Introduction

Parasitic infections affect billions of people globally and cause a massive socioeconomic burden[1,2,3,4]. They are usually associated with low-income countries, parasitic infections are becoming an increasing health concern in developed countries. Motility is common among disease-causing organisms, from unicellular pathogenic bacteria and parasitic protozoa to multicellular parasitic worms and ectoparasites. The ability of an organism to move from one location to another location has distinct benefits for successful infection and transmission, and motility is often central to virulence[5,6,7]. Despite the importance of motility for a parasitic lifestyle, parasite motility remains an understudied area of research, and motility-based diagnostics are considerably underexplored

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Conclusion