Encyclopedias are a good place to start in order to get background info, brainstorm, and find topic ideas. I typed in the keywords infectious disease* AND encyclopedia and found this example. You can narrow your search to e-books only.
Some encyclopedias are available and can be checked out. Others cannot be checked out. Many encyclopedias are online. Use the RIT Libraries Catalog below to find encyclopedias and books on your chosen topic. I also did a search for coronavirus and found this recent book.
You can also use the CREDO Reference database to find information about your topic.