How sad.
While you fear for your safety, you are concerned about getting bitten, and to add to that is my concern about fire safety...
Well you can mount the screen from inside the room.
Any good handy man should be able to do that.
good luck

Interior security bars MUST have a release on the inside for fire escape. If yours don't - REPLACE THEM.
If they're on the exterior and you want to install screens and you can't remove the interior window panes you'll have to remove the exterior bars. They're likely bolted on and can be removed.

Regardless your ability to escape is paramount! Make sure you can get out or the fire department can get in - your life may depend on it.

Most of the time the bars are on the outside.
Just remove the screens from the inside and have them replaced.

I assume you're talking about permanently affixed bars with no release latch on the interior of the home. Most security bars do have an interior latch, for fire escape safety. Is that the situation with yours?