It sounds like you use Webroot Internet Security. I do and I get that a lot. I think the virus is actually some kind of advert wrapper, can't remember name. I generally shut off Webroot and download onto a flash drive so it's isolated. Then I restart Webroot and scan the file on the flashdrive.
Normally, it passes as the notice generally only shows up during download. If the scan does find something, Webroot gets rid of the virus/malware but leaves the manga/dojinshi which I can then put on my PC or tablet to enjoy. Of course scan the PC too.
I've never had a problem doing it that way, but if you're nervous, I recommend using an old tablet to download onto. Webroot does have an Android app, or there are many other free virus programs to put on the tablet. After DL, scan, cleanse if needed, then you can xfer to PC or email to yourself to xfer.