Friday, April 4, 2025
4/4/2025
Insights into infection of Ilheus virus in mammalian and mosquito cells - SUMMARY Global health is perpetually challenged by emerging and reemerging infectious diseases. In recent times climate change and globalization has contributed to the rampant spread of mosquitos from tropical and subtropical climates into more moderate climates, and thus also the spread of one of the most important mosquito-borne viruses namely flaviviruses. These viruses can cause asymptomatic, mild infection as well as severe disease such as encephalitis and death. Thus, understanding the foundational molecular virology, virus-host interactions, transmission, and pathogenesis is critical to limiting the disease burden of flaviviruses, especially as licensed antivirals and vaccines are limited. In this application we propose to investigate Ilheus virus (ILHV), an understudied mosquito-borne flavivirus with the potential to emerge. ILHV cause disease in humans, and in different animal and bird species. The virus has primarily been isolated from Culex, Aedes and Psorophora mosquitoes. To date, the following types of studies on ILHV have been conducted: surveillance and serological studies of ILHV in the Americas, sequence analysis of the different isolates, crystal structure of the ILHV NS3 protein, a cross protection study for the related Rocio virus, and anti-ILHV effects of caffeic acid. There is however no research investigating the kinetics of ILHV infection in mammalian and mosquito cells, nor the availability of an infectious clone that would permit manipulation of the viral genome for mechanistic studies. Given that the R03 Small Research Grant program is directed towards early and feasibility projects, research projects with limited scope or generation of new methods and tools, we propose that our application is ideally suited to this funding mechanism. In Aim 1, we will examine ILHV infection in different mammalian, bird, and mosquito cell lines, as well as primary skin and monocyte cultures. We will also examine the activation of the innate immune response and expression of select interferon stimulated genes. In Aim 2, we intend to construct an infectious clone and subgenomic nanoluciferase reporter replicon. Flaviviruses use complementary sequences in the 5’ and 3’ untranslated regions of the RNA genome to facilitate cyclization, a step that is critical for virus replication. We will use the infectious clone and subgenomic replicons to characterize the putative cyclization sequences in the ILHV RNA (Aim 2). Completing these Aims will establish the groundwork for important future studies investigating the structure of the ILHV RNA genome, virus-host interactions and vector competence studies that could impact the identification and developments of new antiviral treatment options.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).