Sarcoptes scabiei Suspected Here! FinalSlide
HTGAA 2026 Final Project: Sarcoptes exploit host geometry – developing assay to measure redox landscape in stratum corneum of goat
By Charley Naney
SECTION 1: ABSTRACT
Provide an abstract/summary for your project. (minimum 150 words) • Should be a self-contained description of the project • Should contain brief outline of: Significance: The ectoparasitic mite Sarcoptes scabiei exploits the stratum corneum of mammalian skin, including hosts within the Bovidae family (subfamily Caprinae), notably the genera Capra (goats) and Ovis (sheep). While S. scabiei infects a broad range of mammals, this project focuses on caprine hosts (Capra), which provide a tractable and agriculturally relevant system. Goats and sheep share a common ancestor within Caprinae but diverged approximately 4–5 million years ago, adapting to distinct ecological geometries. Goats evolved in heterogeneous, vertical, and discontinuous mountain environments, whereas sheep adapted to more homogeneous, open, and flock-oriented landscapes. These divergent ecological pressures have shaped not only behavior and morphology but potentially the spatial structure of skin physiology, including barrier properties, microenvironmental heterogeneity, and host–parasite interactions. Sarcoptes scabiei is a globally distributed, highly contagious parasite of major veterinary and public health concern. Cross-host transmission is frequently observed in practice: infestations in sheep may spread to goats, dogs, and humans in shared environments, reflecting the long cohabitation of these species under both natural and artificial selection over the past 8,000–10,000 years. This deep ecological and evolutionary entanglement suggests that Sarcoptes scabiei operates within host-derived microenvironments that are conserved enough to permit transmission, yet variable enough to shape infection dynamics. This project introduces a spatially resolved diagnostic concept: rather than sampling lesions indiscriminately, it targets the peri-lesional boundary, hypothesized to represent a localized maximum in reactive oxygen species (ROS) generated by host immune activity. By developing a small-scale assay—potentially leveraging fluorescent ROS probes—to detect this spatial oxidative signature, I aim to create a rapid, geometry-informed approach to identifying mite-associated lesions. While species-level discrimination of Sarcoptes lineages may not be feasible within the project timeline, this approach can be strengthened through triangulation, integrating spatial ROS signals with observational and survey-based metadata (host species, lesion morphology, transmission context). Together, these elements may yield a more robust and field-deployable diagnostic framework. Beyond immediate application, this work addresses a broader evolutionary and biophysical question: how parasites exploit host tissue geometry to create stable microenvironments, and how those environments can be detected through their spatial redox signatures. In this sense, Sarcoptes scabiei infection becomes not only a veterinary problem, but a model system for understanding how geometry, evolution, and immune dynamics converge in living tissue. Broad objectives: I will develop spaitially resolved diagnostic assay for detecting Sarcoptes scabiei infection, or evidence of burrows in epidermal layers of skin, using fluorescent ROS probes capable of detecting oxidative stress signature in caprine skin. This approach will include farmer education and a survey for targeting host and environmental metadata, and skin targeting of peri-lesional microenvironments. Testing data can later be combined with transcriptomic sequencing, as other researchers are starting to do to develop putative genes that can be analyzed to develop more exact assay-based biomarkers for diagnosis, prognosis, and more targeted therapy with effective surveillance, as only a recovering Epidemiologist, goat and sheep farmer, returned to Evolutionary Microbiology can dream up. Hypotheses: Sarcoptes scabiei infection or infestation, need to decide on best state variable terminology here, is a pathogenic process involving reorganization of the geometry of the stratum corneum. The mites burrow to feed, make shelter, and lay eggs which results in a diffusion-constrained microenvironment ideal for assaying host immune responses surrounding, including what I hypothesize to be a localized region with maximum concentration of ROS distributed within a peri-lesional boundary. Specific aims Null Hypothesis: In probable Sarcoptes scabiel infested goats, ROS levels will be uniformly distributed across lesion core, peri-lesional boundary tissue, with no spaitial enrichment at lesion boundary. Alternative Hypothesis: In probable Sarcoptes scabiel infested goats, a localized maximum of ROS at the peri-lesional boundary in caprine skin will be present.
