Imaging & identification of malaria parasites using cellphone microscope with a ball lens

Neglected tropical disease (NTD) diagnostics: current development and operations to advance control

Neglected tropical diseases (NTDs) have become important public health threats that require multi-faceted control interventions. As late treatment and management of NTDs contribute significantly to the associated burdens, early diagnosis becomes an important component for surveillance and planning effective interventions. This review identifies common NTDs and highlights the progress in the development of diagnostics for these NTDs. Leveraging existing technologies to improve NTD diagnosis and improving current operational approaches for deployment of developed diagnostics are crucial to achieving the 2030 NTD elimination target. Point-of-care NTD (POC-NTD) diagnostic tools are recommended preferred diagnostic options in resource-constrained areas for mapping risk zones and monitoring treatment efficacy. However, few are currently available commercially. Technical training of remote health care workers on the use of POC-NTD diagnostics, and training of health workers on the psychosocial consequences of these diagnostics are critical in harnessing POC-NTD diagnostic potential. While the COVID-19 pandemic has challenged the possibility of achieving NTD elimination in 2030 due to the disruption of healthcare services and dwindling financial support for NTDs, the possible contribution of NTDs in exacerbating COVID-19 pandemic should motivate NTD health system strengthening.

A high-performance cell-phone based polarized microscope for malaria diagnosis

We present a cell-phone based polarized microscope for diagnosing malaria through hemozoin recognition over a wide field-of-view (FOV) accompanied with decent image performance. The system is constructed based on attachment method using a lens assembly as objective, two mobile phones and two linear polarizers. A ~0.92 μm resolution across a FOV of ~3.27 mm × 3.27 mm with high imaging quality is realized, demonstrating an increased resolving power, four times improvement in FOV and better imaging quality over mobile-optical-polarization imaging device. Importantly, we also demonstrate it has capability of recognizing hemozoin within the sample for malaria diagnosis by imaging malaria-infected blood samples with similar sensitivity comparable to Leica microscopy. It is more compact, portable, and insensitive to alignment, making it highly suitable for malaria detection in a portable, easy to setup and use way in low-resource areas.

A review on innovative optical devices for the diagnosis of human soil-transmitted helminthiasis and schistosomiasis: from research and development to commercialization

Diagnosis of soil-transmitted helminth (STH) and schistosome infections relies largely on conventional microscopy which has limited sensitivity, requires highly trained personnel and is error-prone. Rapid advances in miniaturization of optical systems, sensors and processors have enhanced research and development of digital and automated microscopes suitable for the detection of these diseases in resource-limited settings. While some studies have reported proof-of-principle results, others have evaluated the performance of working prototypes in field settings. The extensive commercialization of these innovative devices has, however, not yet been achieved. This review provides an overview of recent publications (2010–2022) on innovative field applicable optical devices which can be used for the diagnosis of STH and schistosome infections. Using an adapted technology readiness level (TRL) scale taking into account the WHO target product profile (TPP) for these diseases, the developmental stages of the devices were ranked to determine the readiness for practical applications in field settings. From the reviewed 18 articles, 19 innovative optical devices were identified and ranked. Almost all of the devices (85%) were ranked with a TRL score below 8 indicating that, most of the devices are not ready for commercialization and field use. The potential limitations of these innovative devices were discussed. We believe that the outcome of this review can guide the end-to-end development of automated digital microscopes aligned with the WHO TPP for the diagnosis of STH and schistosome infections in resource-limited settings.

Schistoscope: An Automated Microscope with Artificial Intelligence for Detection of Schistosoma haematobium Eggs in Resource-Limited Settings

For many parasitic diseases, the microscopic examination of clinical samples such as urine and stool still serves as the diagnostic reference standard, primarily because microscopes are accessible and cost-effective. However, conventional microscopy is laborious, requires highly skilled personnel, and is highly subjective. Requirements for skilled operators, coupled with the cost and maintenance needs of the microscopes, which is hardly done in endemic countries, presents grossly limited access to the diagnosis of parasitic diseases in resource-limited settings. The urgent requirement for the management of tropical diseases such as schistosomiasis, which is now focused on elimination, has underscored the critical need for the creation of access to easy-to-use diagnosis for case detection, community mapping, and surveillance. In this paper, we present a low-cost automated digital microscope—the Schistoscope—which is capable of automatic focusing and scanning regions of interest in prepared microscope slides, and automatic detection of Schistosoma haematobium eggs in captured images. The device was developed using widely accessible distributed manufacturing methods and off-the-shelf components to enable local manufacturability and ease of maintenance. For proof of principle, we created a Schistosoma haematobium egg dataset of over 5000 images captured from spiked and clinical urine samples from field settings and demonstrated the automatic detection of Schistosoma haematobium eggs using a trained deep neural network model. The experiments and results presented in this paper collectively illustrate the robustness, stability, and optical performance of the device, making it suitable for use in the monitoring and evaluation of schistosomiasis control programs in endemic settings.

The Field Guide to 3D Printing in Optical Microscopy for Life Sciences

The maker movement has reached the optics labs, empowering researchers to create and modify microscope designs and imaging accessories. 3D printing has a disruptive impact on the field, improving accessibility to fabrication technologies in additive manufacturing. This approach is particularly useful for rapid, low-cost prototyping, allowing unprecedented levels of productivity and accessibility. From inexpensive microscopes for education such as the FlyPi to the highly complex robotic microscope OpenFlexure, 3D printing is paving the way for the democratization of technology, promoting collaborative environments between researchers, as 3D designs are easily shared. This holds the unique possibility of extending the open-access concept from knowledge to technology, allowing researchers everywhere to use and extend model structures. Here, it is presented a review of additive manufacturing applications in optical microscopy for life sciences, guiding the user through this new and exciting technology and providing a starting point to anyone willing to employ this versatile and powerful new tool.

An affordable, handheld multimodal microscopic system with onboard cell morphology and counting features on a mobile device

A simple yet effective, handheld and flexible bright-field and fluorescence microscopic platform on a smartphone with varying optical magnifications is reported for morphological analysis and onboard cell counting features.

Shielding of viruses such as SARS-Cov-2 from ultraviolet radiation in particles generated by sneezing or coughing: Numerical simulations of survival fractions

SARS-CoV-2 and other microbes within aerosol particles can be partially shielded from UV radiation. The particles refract and absorb light, and thereby reduce the UV intensity at various locations within the particle. Previously, we demonstrated shielding in calculations of UV intensities within spherical approximations of SARS-CoV-2 virions within spherical particles approximating dried-to-equilibrium respiratory fluids. The purpose of this paper is to extend that work to survival fractions of virions (i.e., fractions of virions that can infect cells) within spherical particles approximating dried respiratory fluids, and to investigate the implications of these calculations for using UV light for disinfection. The particles may be on a surface or in air. Here, the survival fraction (S) of a set of individual virions illuminated with a UV fluence (F, in J/m²) is assumed described by S(kF) = exp(-kF), where k is the UV inactivation rate constant (m²/J). The average survival fraction (S_p) of the simulated virions in a group of particles is calculated using the energy absorbed by each virion in the particles. The results show that virions within particles of dried respiratory fluids can have larger S_p than do individual virions. For individual virions, and virions within 1-, 5-, and 9-µm particles illuminated (normal incidence) on a surface with 260-nm UV light, the S_p = 0.00005, 0.0155, 0.22, and 0.28, respectively, when kF = 10. The S_p decrease to <10^-7, <10^-7, 0.077, and 0.15, respectively, for kF = 100. Results also show that illuminating particles with UV beams from widely separated directions can strongly reduce the S_p. These results suggest that the size distributions and optical properties of the dried particles of virion-containing respiratory fluids are likely important to effectively designing and using UV germicidal irradiation systems for microbes in particles. The results suggest the use of reflective surfaces to increase the angles of illumination and decrease the S_p. The results suggest the need for measurements of the S_p of SARS-CoV-2 in particles having compositions and sizes relevant to the modes of disease transmission.

The construction of high-magnification homemade lenses for a simple microscope: an easy "DIY" tool for biological and interdisciplinary education

The rise of microscopy in the seventeenth century allowed scientists to discover a new world of microorganisms and achieve great physiological advances. One of the first microscopes of the epoch was Antonie van Leeuwenhoek's microscope, a deceptively simple device that contains a single ball lens housed in a metal plate allowing the observation of samples at up to ×250 magnification. Such magnification was much greater than that achieved by rudimentary compound microscopes of the era, allowing for the discovery of microscopic, single-celled life, an achievement that marked the study of biology up to the nineteenth century. Since Leeuwenhoek's design uses a single ball lens, it is possible to fabricate variations for educational activities in physics and biology university and high school classrooms. A fundamental problem, however, with home-built microscopes is that it is difficult to work with glass. We developed a simple protocol to make ball lenses of glass and gelatin with high magnification that can be done in a university/high school classroom, and we designed an optimized support for focusing and taking photographs with a smartphone. The protocol details a simple, easily accessible, low-cost, and effective tool for the observation of microscopic samples, possible to perform anywhere without the need for a laboratory or complex tools. Our protocol has been implemented in classrooms in Chile to a favorable reception.

Cellulose-based micro-fibrous materials imaged with a home-built smartphone microscope

Micro-fibrous materials are one of the highly explored materials and form a major component of composite materials. In resource-limited settings, an affordable and easy to implement method that can characterize such material would be important. In this study, we report on a smartphone microscopic system capable of imaging a sample in transmission mode. As a proof of concept, we implemented the method to image handmade paper samples-cellulosic micro-fibrous material of different thickness. With 1 mm diameter ball lens, individual cellulose fibers, fiber web, and micro-porous regions were resolved in the samples. Imaging performance of the microscopic system was also compared with a commercial bright field microscope. For thin samples, we found the image quality comparable to commercial system. Also, the diameter of cellulose fiber measured from both methods was found to be similar. We also used the system to image surfaces of a three ply surgical facemask. Finally, we explored the application of the system in the study of chemical induced fiber damage. This study suggested that the smartphone microscope system can be an affordable alternative in imaging thin micro-fibrous material in resource limited setting.

Internet of medical things (IoMT)-integrated biosensors for point-of-care testing of infectious diseases

On global scale, the current situation of pandemic is symptomatic of increased incidences of contagious diseases caused by pathogens. The faster spread of these diseases, in a moderately short timeframe, is threatening the overall population wellbeing and conceivably the economy. The inadequacy of conventional diagnostic tools in terms of time consuming and complex laboratory-based diagnosis process is a major challenge to medical care. In present era, the development of point-of-care testing (POCT) is in demand for fast detection of infectious diseases along with “on-site” results that are helpful in timely and early action for better treatment. In addition, POCT devices also play a crucial role in preventing the transmission of infectious diseases by offering real-time testing and lab quality microbial diagnosis within minutes. Timely diagnosis and further treatment optimization facilitate the containment of outbreaks of infectious diseases. Presently, efforts are being made to support such POCT by the technological development in the field of internet of medical things (IoMT). The IoMT offers wireless-based operation and connectivity of POCT devices with health expert and medical centre. In this review, the recently developed POC diagnostics integrated or future possibilities of integration with IoMT are discussed with focus on emerging and re-emerging infectious diseases like malaria, dengue fever, influenza A (H1N1), human papilloma virus (HPV), Ebola virus disease (EVD), Zika virus (ZIKV), and coronavirus (COVID-19). The IoMT-assisted POCT systems are capable enough to fill the gap between bioinformatics generation, big rapid analytics, and clinical validation. An optimized IoMT-assisted POCT will be useful in understanding the diseases progression, treatment decision, and evaluation of efficacy of prescribed therapy.

A smartphone microscopic method for simultaneous detection of (oo)cysts of Cryptosporidium and Giardia

Background

Food and water-borne illness caused by ingestion of (oo)cysts of Cryptosporidium and Giardia is one of the major health problems globally. Several methods are available to detect Giardia cyst and Cryptosporidium oocyst in food and water. Most of the available methods require a good laboratory facility and well-trained manpower and are therefore costly. There is a need of affordable and reliable method that can be easily implemented in resource limited settings.

Methodology/Principle findings

We developed a smartphone based microscopic assay method to screen (oo)cysts of Cryptosporidium and Giardia contamination of vegetable and water samples. The method consisting of a ball lens of 1 mm diameter, white LED as illumination source and Lugols's iodine staining provided magnification and contrast capable of distinguishing (oo)cysts of Cryptosporidium and Giardia. The analytical performance of the method was tested by spike recovery experiments. The spike recovery experiments performed on cabbage, carrot, cucumber, radish, tomatoes, and water resulted in 26.8±10.3, 40.1±8.5, 44.4±7.3, 47.6±11.3, 49.2 ±10.9, and 30.2±7.9% recovery for Cryptosporidium, respectively and 10.2±4.0, 14.1±7.3, 24.2±12.1, 23.2±13.7, 17.1±13.9, and 37.6±2.4% recovery for Giardia, respectively. The spike recovery results are comparable with data obtained using commercial brightfield and fluorescence microscope methods. Finally, we tested the smartphone microscope system for detecting (oo)cysts on 7 types of vegetable (n = 196) and river water (n = 18) samples. Forty-two percent vegetable and thirty-nine percent water samples were found to be contaminated with Cryptosporidium oocyst. Similarly, thirty-one percent vegetable and thirty-three percent water samples were contaminated with Giardia cyst.

Conclusions

The newly developed smartphone microscopic method showed comparable performance to commercial microscopic methods. The new method can be a low-cost and easy to implement alternative method for simultaneous detection of (oo)cysts in vegetable and water samples in resource limited settings.

Food and water-borne illness arising from the consumption of contaminated food and water are serious health hazards globally. Cryptosporidium and Giardia are the major food and water‒borne parasites. The infection occurs mainly by (oo)cyst phase of the parasites. People in developing countries are more vulnerable to these parasites where infection is more likely underdiagnosed and underreported due to limited resources for detection. There is need of a method that is affordable and easy to implement. In this study, we developed and optimized a novel smartphone microscope method that can detect and quantify the (oo)cyst of the parasites in food and water samples. The developed method is easy to implement and affordable and provides similar performance to the other commercially available microscopic methods.

Breath variability increases in the minutes preceding obstructive sleep apneic events

PURPOSE

It is unclear if there is a consistent signature in breath patterns prior to an impending obstructive apneic event in patients with sleep-disordered breathing (SDB).

OBJECTIVE

To use continuous recordings of ambient sound in sleep using a smartphone to track auditory signatures of breaths and measure their regularity preceding apneic events.

METHODS

We studied 50 patients evaluated for SDB in whom sound was recorded using smartphones concurrently with polysomnography (PSG). Whole-night sound files were analyzed for time and frequency domain analyses of breath periodicity during periods of normal and sleep-disordered breathing.

RESULTS

Fifty patients (44% women, 42.0 ± 9.4 years old, BMI 32.8 ± 10.8 kg/m²) recorded sound, of whom 30 were diagnosed with OSA and 20 were not. We analyzed a total of 497 apneic (≥10 s) and 481 non-apneic intervals, confirmed by PSG. Interbreath intervals were 3.75 ± 0.62 s for 1 min in quiet breathing, with SD 1.11 ± 0.48 s that increased to 4.16 ± 3.06 s in successive 60-s epochs up to apnea (p < 0.001). Interbreath SD in the 60 s immediately preceding apnea was higher than the SD in random non-apneic periods (p < 0.01, ANOVA). Interbreath SD ≥1.49 s gave 87.3% sensitivity and 86.5% specificity for predicting apnea in the next minute (c-statistic 0.94).

CONCLUSIONS

Breaths increase in variability minutes before proven obstructive apnea in patients with suspected SDB. These results suggest that it may be possible to predict and thus potentially avert apneic events and provide insights into events leading to SDB.

TRIAL REGISTRATION

NCT03288376, clinicaltrials.org.

Diagnostic Techniques of Soil-Transmitted Helminths: Impact on Control Measures

Soil-transmitted helminth (STH) infections are common in the tropical and subtropical countries. The burden of disease is highest in endemic areas with limited access to good quality water supply and poor sanitary conditions. Major approaches to control and reduce morbidity caused by worm infections include the periodic deworming of pre-school and school-aged children with anthelminthic drugs. Population-based studies and individual patient management including interventional studies can only be successful when accurate diagnostic techniques are used. The lack of appropriate diagnostic tools providing accurate results concerning both infectious status and intensity of infection-as these two factors vary in regions of low infection intensities-is a major challenge. Currently, available techniques show limited sensitivity and specificity and as such, a combination of several techniques is usually used to diagnose the large variety of parasite species. The objective of this review was to describe the advantages and disadvantages of the different available techniques for the diagnosis of STH infections and to highlight their use in control programs.

Rapid detection of Escherichia coli using bacteriophage-induced lysis and image analysis

Rapid detection of bacterial pathogens is a critical unmet need for both food and environmental samples such as irrigation water. As a part of the Food safety Modernization Act (FSMA), The Produce Safety rule has established several requirements for testing for the presence of generic Escherichia coli in water, but the current method available for testing (EPA M1603) demands specified multiple colony verification and highly trained personnel to perform these tests. The purpose of the study was to assess a phage induced bacterial lysis using quantitative image analysis to achieve rapid detection of E. coli at low concentrations within 8 hours. This study aimed to develop a simple yet highly sensitive and specific approach to detect target bacteria in complex matrices. In the study, E. coli cells were first enriched in tryptic soy broth (TSB), followed by T7 phage induced lysis, concentration, staining and fluorescent imaging. Image analysis was conducted including image pre-processing, image segmentation and quantitatively analysis of cellular morphological features (area, eccentricity and full width at half maximum). Challenge experiments using realistic matrices, including simulated fresh produce wash water, coconut water and spinach wash water, demonstrated the method can be applied for use in situations that occur in food processing facilities. The results indicated E. coli cells that are lysed by T7 phages demonstrated significantly (P < 0.05) higher extracellular DNA release, altered cellular shape (from rod to circular) and diffused fluorescent signal intensity. Using this biosensing strategy, a sensitivity to detect Escherichia coli at 10 CFU/ml within 8 hours was achieved, both in laboratory medium and in complex matrices. The proposed phage based biosensing strategy enables rapid detection of bacteria and is applicable to analysis of food systems. Furthermore, the steps involved in this assay can be automated to enable detection of target bacteria in food facilities without extensive resources.

Cell phone digital microscopy using an oil droplet

We introduce an accessible cell phone imaging method using small droplets of microscope immersion oil and consumer-grade oils. Oil droplets were more resistant to evaporation than water droplets, and they resolved cellular structures that were visible using a 20x/0.75 objective. We optically characterized the droplets using a cell phone screen and resolution target. We further obtained cellular resolution images of an onion epidermis and a zea stem cross-section sample. Our droplet-based method enables stable optical imaging for diagnostic and educational purposes without custom setups, specialized components, or manufacturing processes.