Microscopy in Mongolia
SUMMARY
This project aimed to establish the feasibility of the CellScope as a tool for veterinary telemedicine. Specifically, the project aimed to 1), validate the CellScope as an instrument able to image blood films of veterinary species (horses, cattle, sheep, goats and camelids) with diagnostic fidelity comparable to conventional techniques and 2), to evaluate the ability of the CellScope to transmit accurate diagnostic information of blood films taken from livestock to experts from remote field sites in Mongolia.
Samples from species relevant to veterinary medicine in Mongolia were collected across multiple sites and ecologies. Slides were prepared from these samples per standard techniques. The slides were imaged by the CellScope and complete blood cell counts (CBC) were performed on the slides by conventional techniques and the image sets of the same slides.
The CellScope was found to be an excellent collector of images and captures almost all the details necessary to perform a CBC. Particularly, leukocyte differentials were difficult, but still possible. Yet, the number of images we acquired would already be prohibitive to the use of the CellScope for remote CBCs since the size of the data to be transmitted would not be supported by current cellular infrastructure in the countries that the CellScope might be used in. That being said, there are a number of other diagnostic tests that can be performed on a manageably small set of images or even a single image. Fecal smears, floats, and sediments, for example, would require a small number of images each. Indeed, we successfully demonstrated the identification of multiple species of parasites using such remotely transmitted images. Furthermore, continued development of the supporting software could potentially make the transmitted data size more manageable for diagnostic tests such as CBCs that might require a larger data set.
In the future, the CellScope could readily see wider deployment to sites in multiple ecologies for early detection of a large variety of diseases relevant to veterinary medicine.
HYPOTHESIS
The CellScope can image blood films of domestic animal species with the fidelity to perform accurate complete blood counts (CBC). These diagnostic images can be acquired and transmitted to hematology and clinical pathology experts to facilitate disease monitoring and/or emerging pathogen surveillance in livestock and wildlife.
METHODS
The CellScope was investigated for its feasibility previous to deploying it for field study. Due to the transition from using the originally proposed technology to the CellScope, the parameters of this preliminary investigation had to change. The CellScope imaging platform is immediately familiar to the user of a benchtop microscope. The inventors have already conducted studies characterizing its performance and as such, the metrics that the preliminary investigation would have yielded have already been quantified. Nonetheless, a veterinary pathologist qualified the images taken by the CellScope as of comparable quality to a benchtop microscope and specifically that the images capture all the features relevant to perform a CBC (e.g. nucleus morphology for leukocyte differential).
In the field, 181 samples from horses, cattle, sheep, goats and camelids were collected across sites in Govi-Altai aimag (province), Terelj National Park area, and Hustai National park area. Slides were prepared by smearing a droplet across the slide with a second slide. Slides were allowed to air dry, then were fixed and stained with a modified Giemsa (Diff-quik) kit. Of the total pool, a representative set was selected for imaging and CBC analysis. For each selected slide, images were taken in areas where ~50% of the RBCs were touching, i.e. the readable monolayer, as per standard CBC practice. 10 images were taken of fields that included red blood cells (RBCs) and at least 100 white blood cells (WBCs) were captured in as many images as necessary. 2 images were taken of the feathered edge of the film to confirm slide integrity. The image sets from each of the slides were transmitted to a veterinary pathologist along with the original slides. The pathologist performed CBCs on each the original slides, then performed CBCs based on each of the image sets. Image set analysis order was purposefully uncorrelated to the slide analysis order to prevent bias.
RESULTS
(available by request)
DISCUSSION
The approach and methods were successful in showing that the CellScope can be used for telemedicine applications and exploring the largely unexplored field of remote medicine. Diagnostic telemedicine, in the broad strokes, focuses on removing a prohibitive step from the process of moving from a sample being collected to a diagnosis being delivered. In Mongolia and other countries with a large livestock-dependent population, veterinary infrastructure can be lacking. The existing personnel are spread too thin and the cost in both time and money make sending any but a minimum of samples out for diagnosis in local or foreign labs make access to veterinary care largely unavailable or impractical. In this project, the CellScope was used to transmit data about the samples for remote diagnoses, thus removing the prohibitive step of needing veterinary personnel to travel long distances to take samples and send them away for diagnosis. In this, the project was successful in demonstrating the ability to transform samples into data that can be used to remotely form a diagnosis. It will be up to larger scale deployment of the CellScope, or likely a future iteration of the device, to determine the broad scale impact of wider usage on the veterinary ecology of the country.
Telemedicine is a growing field and the methods and approaches for attempting to make an actionable diagnosis in the field are still early in their evolution. The usage of the CellScope for telemedicine is also relatively new and how it should be used to capture data relevant to make diagnoses still needs to be codified. For example, the method used in this project for imaging leukocytes can be modified such that the operator uses a randomized scanning pattern to prevent scan bias during image acquisition. Additionally, modifications to the hardware of the CellScope will make it easier to standardize its usage.
Possibly the most important contribution this study presents is to highlight the need for methodological innovation in assessment of telemedicine devices. The methods used in this project were based on the best information available, but methodologies for remote manual CBCs based on image sets have not been much explored. Further study is needed to test its validity or find a better method.
PERSONAL THOUGHTS
The story of bringing a microscope out into the remote plains and steppe of Mongolia and seeing if pictures of blood slides can be taken with it may not seem very attention-grabbing at its face. In reality, though, the story told by this project has a great deal to connect with.
The CellScope is an excellent example of engineering ingenuity presented in an accessible manner. With the popularity of DIY/Maker movement, the 3D printed shell and commercial optics composes a device not dissimilar to some found in home labs and collaborative engineering spaces. Among the global health and telemedicine communities, this project presents an appreciable thrust in what has been demonstrated as a good direction. The device we use is cheap to manufacture, easy to train on, rugged, and able to connect into already existing infrastructure. We are working with what is arguably the largest live-stock dependent population in the world and one that is hard to break into for much of the medical community. This project represents the One Health initiative very well in its integration into current infrastructure and its ready application to studying and managing the interface between people and the environment around them, e.g. spread of disease among livestock, livestock’s interaction with wildlife.
AN ANECDOTE
We had just finished the last day of our sample collection at a ger camp in Hustai National Park, home to the famous Przewalski horse. The end of the day involved a field test of the CellScope. The sun had just set over one edge of the valley and a fierce wind began picking up the small particles of earth. The dust struck a harsh tattoo on the side of the jeeps as we assembled our field microscope on the tailgate. Huddled from the wind with our bandanas drawn up to protect our face from the swirling dust, we must have appeared somewhat odd amongst the prize racing horses pawing the ground, Bankhar puppies milling about our feet, and cows softly complaining. Leaning close in as we mounted our first sample, I squinted through the dust to see the display as the microscopic world pops into view. We are able to see the cells that make up the blood of the animal beside us and count their numbers. We are able to see the microscopic parasites that live in its gut. We are able to see all this with our untrained eyes and we imagine what could be accomplished by another dozen such pairs of eyes equipped with the power to peer into the microscopic world. Just by documenting what they see, they have the power to bring the global medical community to bear on monitoring the spread of a disease among their livestock and livelihood.
It was a wonderful moment where the possible impact and reach of the project was so wonderfully connected to the moment-to-moment work of executing a scientific hypothesis. It is a moment I hope to repeat in my future endeavors.
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