Analysis of menisci formed on cones for single field of view parasite egg microscopy

• Published in: Journal of microscopy (Oxford) Vol. 257; no. 2; pp. 133 - 141
• Main Authors: COOKE, I.R, LAING, C.J, WHITE, L.V, WAKES, S.J, SOWERBY, S.J
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.02.2015; Wiley
• Subjects: Animals; Eggs; Feces - parasitology; Helminthiasis - diagnosis; Intestinal Diseases, Parasitic - diagnosis; Meniscus; Microscopes; Microscopy; Microscopy - methods; parasite; Parasites; Parasites - cytology; Physics; Specimen Handling - methods; Zygote - cytology; parasite; microscopy; Meniscus
• ISSN: 0022-2720; 1365-2818
• DOI: 10.1111/jmi.12192

Summary Parasite ova caused to accumulate in a single microscopic field simplifies monitoring soil‐transmitted helminthiasis by optical microscopy. Here we demonstrate new egg‐accumulating geometries based on annular menisci formed on the surface of a wetted cone. Fluidic features extracted from profile images of the system provided mathematical representations of the meniscus gradient that were compared quantitatively to numerical solutions of an axisymmetric Young–Laplace equation. Our results show that the governing dynamics of these systems is dominated by the surface tension of the fluid. These image analysis and mathematical tools provide simple quantitative methods for system analysis and optimization. Lay Description The diagnosis of gastrointestinal worms in animals and people by the visual identification of microscopic nematode eggs in stool can be simplified using of a specially designed fluid cell. The fluid cell collects the eggs at a specified location and a single microscope image showing the collected eggs can be recorded and transmitted for remote analysis. This process removes the manual searching of traditional microscope slides and allows remote location diagnosis of parasite disease. The fluid cell uses the natural curvature of a liquid droplet to passively direct the parasite eggs to the collection area. Using simple image analysis and mathematical modeling tools we have developed a better understanding of the key features of the liquid curvature in one configuration of the fluid cell. These tools can be applied to other configurations of fluid cell to further improve parasite diagnosis by optical microscopy.