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Current Projects
Orthobunyavirus Virus Pathogenesis
Orthobunyavirus Virus Pathogenesis
I have been working on multiple projects involving the development of animal models for studying Cache Valley virus (CVV) pathogenesis, for the overall goal of applying these models to validate vaccines and therapeutics. One project aims to develop a mouse-adapted strain of CVV for the purpose of creating an immune-competent mouse model for CVV. Currently, there is only one small animal model for studying CVV, but it requires the use of an immune-incompetent strain of mouse which Natural strains of CVV have not shown the ability to induce any disease in immune-competent mice. However, our mouse-adapted strain induces weight loss, tissue tropism, and mortality. This involved doing serial passaging of CVV through multiple strains of mice to adapt the virus to immune-competent mice. We also explored the potential for various poultry species to be reservoir hosts for CVV. We showed that although CVV grows rapidly and to very high titers in Chicken, Duck, and Quail cell cultures, the virus is unable to induce disease or an immune response live birds. Implying that although birds do not currently play a role in the maintenance or spread of CVV, they are a prime candidate for potential spillover (Lopez et al. in review).
Cache Valley virus (CVV) is an understudied Orthobunyavirus with a high spillover transmission potential due to its wide geographic distribution and large number of associated wildlife hosts and vectors. Although CVV is known to be widely distributed throughout North America, no studies have explored its geography or employed computational methods to explore the mammals and mosquito species likely participating in the CVV sylvatic cycle. We used a literature review and online databases to compile locality data for CVV and its potential vectors and hosts. We linked location data points with climatic data via ecological niche modeling to estimate the geographical range of CVV and hotspots of transmission risk. Using background similarity tests to identify likely CVV mosquito vectors and mammal hosts to detect ecological signals from CVV sylvatic transmission. CVV distribution maps revealed a widespread potential viral occurrence throughout North America. The background similarity tests identified Aedes vexans, Culiseta inornata, and Culex tarsalis as the most likely vectors and Odocoileus virginianus (white-tailed deer) as the most likely host sustaining sylvatic transmission. We concluded that large areas of North America have suitable climate, vectors, and hosts for CVV emergence, establishment, and spread.
Mosquito Diversity
Mosquito Diversity
Over the last year I have been involved in a vector biology project via my postdoctoral lab's arbovirus surveillance program. We collected mosquitoes across the state of Virginia via CO2 baited CDC light traps, gravid traps, and BG sentinel traps, sorted these to look at both the mosquito and viral diversity across various gradients in the state of Virginia. We found that abundance and richness is highest in the eastern swamps, but the communities are more even in the western mountain sites.
Grassland Bird Ecology
Grassland Bird Ecology
I have conducted wintering ecology research on birds for the last decade. This is an extremely understudied section of the life-cycle of migratory birds, even though it is listed repeatedly as a research need/ priority for conservation and management of at risk species. My research answers an urgent call within the conservation science community to better understand full life-cycle dynamics of migratory species. A case in point involved 6 years of monitoring wintering habitat use and landscape-level movements of longspurs and pipits, a suite of grassland birds that make Oklahoma and Texas the core of their non-breeding range. Some of these species, particularly the grassland obligates Thick-billed (Rhynchophanes mccownii) and Chestnut-collared (Calcarius ornatus) Longspurs, which have experienced drastic population declines over the past half-century causing them to attract conservation attention at global and state levels.
John A. Muller, Joseph A. Veech and Richard Kostecke. Landscape Scale Habitat Associations of Sprague’s Pipit (Anthus spragueii) Overwintering in the Southern United States. Journal of Field Ornithology 89 (4): 326-336. (2018)
John A. Muller and Jeremy D. Ross. Fine-scale habitat associations of Oklahoma’s longspurs. Journal of Wildlife Management 86 (6): e22258. (2022)
John A. Muller, Nuwanthika Perera, Jeremy D. Ross. Winter space use and sex-ratios of Chestnut-collared Longspurs (Calcarius ornatus) in Oklahoma. Wilson Journal of Ornithology 133(4): 589-600. (2021)
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