Mobile phone and handheld microscopes for public health applications
Authors: Isaac I Bogoch, Johan Lundin, Nathan C Lo, Jason R Andrews
Journal: The Lancet Public Health (2017)

Microscopes are crucial for diagnosis of both communicable and non-communicable diseases, and are an essential tool in public health laboratories; unfortunately, these are not available to more than a billion people who live in resource-constrained settings.1Petti CA Polage CR Quinn TC Ronald AR Sande MA Laboratory medicine in Africa: a barrier to effective health care.Clin Infect Dis. 2006; 42: 377-382Crossref PubMed Scopus (496) Google Scholar Over the past decade, there have been several important advances in the development of low-cost, portable microscopy tools designed for use in resource-limited environments. Handheld microscopes, particularly those interfacing with a mobile phone, hold promise for facilitating the provision of equitable health care to those living in underserviced setings.2Bogoch II Andrews JR Speich B et al.Mobile phone microscopy for the diagnosis of soil-transmitted helminth infections: a proof-of-concept study.Am J Trop Med Hyg. 2013; 88: 626-629Crossref PubMed Scopus (92) Google Scholar, 3Ephraim RK Duah E Cybulski JS et al.Diagnosis of Schistosoma haematobium infection with a mobile phone-mounted Foldscope and a reversed-lens CellScope in Ghana.Am J Trop Med Hyg. 2015; 92: 1253-1256Crossref PubMed Scopus (61) Google Scholar, 4Coulibaly JT Ouattara M D'Ambrosio MV et al.Accuracy of mobile phone and handheld light microscopy for the diagnosis of schistosomiasis and intestinal protozoa infections in Côte d'Ivoire.PLoS Negl Trop Dis. 2016; 10: e0004768Google Scholar Mobile phone microscopes have several attributes that could make them useful in public health practice. The microscopes are portable and battery-powered, hence they can be easily transported to multiple settings and do not require stable grid electricity.3Ephraim RK Duah E Cybulski JS et al.Diagnosis of Schistosoma haematobium infection with a mobile phone-mounted Foldscope and a reversed-lens CellScope in Ghana.Am J Trop Med Hyg. 2015; 92: 1253-1256Crossref PubMed Scopus (61) Google Scholar, 4Coulibaly JT Ouattara M D'Ambrosio MV et al.Accuracy of mobile phone and handheld light microscopy for the diagnosis of schistosomiasis and intestinal protozoa infections in Côte d'Ivoire.PLoS Negl Trop Dis. 2016; 10: e0004768Google Scholar Images can be digitised and software or off-site experts can support the diagnostic process.5Linder E Grote A Varjo S et al.On-chip imaging of Schistosoma haematobium eggs in urine for diagnosis by computer vision.PLoS Negl Trop Dis. 2013; 7: e2547Crossref PubMed Scopus (38) Google Scholar Global positioning system coordinates can be linked to diagnostic results to map disease burden in real time. Cases in which mobile phone microscopes have been successfully used include for detection of malaria,6Coulibaly JT Ouattara M Keiser J et al.Evaluation of malaria disgnosis using a handheld ligh microscope in a community-based setting in rural Côte d'Ivoire.Am J Trop Med Hyg. 2016; 95: 831-834Crossref PubMed Scopus (19) Google Scholar Loa loa,7D'Ambrosio MV Bakalar M Bennuru S et al.Point-of-care quantification of blood-borne filarial parasites with a mobile phone microscope.Sci Trans Med. 2015; 7: 286re4Crossref PubMed Scopus (155) Google Scholar schistosomiasis, and soil-transmitted helminths,8Bogoch II Coulibaly JT Andrews JR et al.Parasitology. 2014; 141: 1811-1818Crossref PubMed Scopus (31) Google Scholar a set of diseases that disproportionately afflict those living in settings with limited access to conventional diagnostics. Also, initial results on applications related to diagnostics of non-communicable diseases show promise and can address the paucity of experts in low-resource settings through remote diagnostic support.9Holmström O Linder N Lundin M et al.Quantification of estrogen receptor-alpha expression in human breast carcinomas with a miniaturized, low-cost digital microscope: a comparison with a high-end whole slide-scanner.PLoS One. 2015; 10: e0144688Crossref Scopus (9) Google Scholar Still, several hurdles lie ahead that must be overcome before implementation and scale-up of mobile microscope technology: validation, durability, sample preparation, and last mile problems. First, before implementation, validation of these devices in real-world conditions—by individuals who will use these devices in their day-to-day public health practice—is crucial to ensure appropriate design and diagnostic operating characteristics. Second, mobile phone microscopes, much like conventional light microscopes, should be durable, and capable of a broad range of diagnoses, rather than being designed for a single purpose, such as malaria diagnoses. Furthermore, a critical limiting factor to the reach of portable microscopes is availability of infrastructure for sample preparation. Even ideal, affordable microscopes will have limited use without similar engineering advances in sample preparation, performed under austere laboratory conditions. Finally, devices must have the ability to overcome the so-called last mile problem in their translation into global health practice, by development of viable strategies for manufacturing, intellectual property, regulation, and business commercialisation to reach the intended population.10Chao TE Lo NC Mody GN Sinha SR Strategies for last mile implementation of global health technologies.Lancet Glob Health. 2014; 2: e497-e498Summary Full Text Full Text PDF PubMed Scopus (9) Google Scholar Mobile phone microscopes are an exciting addition to our public health toolkit. Cooperation between diverse stakeholders—engineers, clinicians, public health providers, government officials, business leaders, and policy makers—can ensure proper design, validation, and implementation of these tools, to enable their translation from the research laboratory to public health uses. JL reports grants from the Swedish Research Council and Finnish Funding Agency for Innovation, fees from Fimmic Oy. University of Helsinki has a patent mobile microscope pending, invented by JL. The invention is related to the use of fluorescence imaging filters combined with inexpensive plastic lenses, and all rights are with the University of Helsinki. JL has also filed a patent slide holder for an optical microscope that is related to motorisation of regular microscopes. All other authors declare no competing interests.