Vector competence of St. Louis encephalitis virus: a systematic review of nearly 100 years of study.
Category: Research Poster
Author(s): Kate Kimball
Presenter(s): Kate Kimball
Mentors(s): Emily Gallichotte
St. Louis encephalitis virus (SLEV) is an orthoflavivirus that infects birds and is transmitted by Culex mosquitoes. However, vector competence (ability of a vector to transmit a virus) varies by species, virus strain and other factors. SLEV was first detected in 1933 in St. Louis, Missouri. It then spread and became endemic throughout the U.S. until the early 2000s. In 2025 SLEV was detected in Fort Collins, re-emerging after over 20 years, posing a risk to both animal and human health. With this re-emergence and likely establishment in Colorado, it is critical to better understand SLEV transmission by mosquitoes, especially locally abundant species. We sought to identify all published experimental SLEV vector competence studies, standardize results, conduct meta-analyses, and define variables impacting outcomes. We conducted a search and identified 109 papers, which were screened using study criteria, resulting in 29 papers. Raw metadata was extracted and standardized, allowing for comparisons. The earliest paper was from 1935 (2 years after SLEV’s discovery), and the most recent was from 2024, spanning almost 100 years. In these papers, SLEV was experimentally tested in 33 mosquito species. Future analyses will compare infection and transmission rates across mosquito species and other variables, to gain a clearer understanding of SLEV vector competence and help inform local transmission risk.