Virginia Via Research Day Book 2026

Medical Student Research Biomedical

04 SILENT INVADERS: NEUROINVASION BY MOSQUITO-BORNE FLAVIVIRUSES

Aashima Sagar, OMS-II; Nisha Duggal, PhD Corresponding author: asagar@vcom.edu

VCOM-Virginia, Blacksburg, Virginia Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia

with unclear neuronal targets; however, with a mild neuronal injury, causing encephalitis in predominantly older or immunocompromised adults. WNV demonstrated the highest degree of robust neuroinflammation and caspase-mediated neuronal apoptosis associated with clinical syndromes such as encephalitis and acute flaccid paralysis. These findings collectively support a gradient between viral neuroinvasion mechanisms and observed clinical severity. Further research is still ongoing. Conclusion: Differences in neuroinvasion pathways and neuronal tropism among the three flavirisues (USUV, SLEV, WNV) correlate with their neurological manifestations. These studies reinforce the importance of a standardized neuropathology reporting system that can expand to human based studies to further elucidate their defined neuropathogenesis.

Context: Usutu Virus (USUV), St. Louis Encephalitis virus (SLEV), and West Nile Virus (WNV) are mosquito-borne flaviviruses that pose a global concern due to their emerging neuroinvasive nature, which threatens human health. Although these viruses are genetically similar and share a similar mosquito-bird transmission cycle, they have varying neurological outcomes with underlying differences in neuroinvasive routes and host response. Understanding how these mechanistic differences can help improve diagnostic accuracy and anticipate future therapeutic strategies. Object/Hypothesis: Objective: To determine whether differences in neuroinvasion mechanisms, neuronal tropism, and neuroinflammatory responses among USUV, SLEV, and WNV can explain their distinct clinical manifestations

Hypothesis: The blood-brain barrier entry mechanism and cell-type specificity for each virus explain the patterns of encephalitis. Methods: Published peer-reviewed literature, including animal model findings and in vitro studies, was used to analyze and compare the blood-brain barrier pathways, cell-type tropism, inflammatory responses, and resulting neuropathology. Data were extracted from neuropathology reports to evaluate the differences in shared and divergent mechanisms across the three viruses. Results: USUV primarily used a transcellular blood-brain entry pathway and exhibited a moderate infection of neurons and astrocytes associated with glial activation and meningoencephalitic presentation. SLEV induced a perivascular inflammation

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2026 Research Recognition Day