AIBU that if you ask me to dog sit...

[TheNewFleabag]

...you make sure you house isn't flea infested? I am now covered in very itchy and painful bites.

It's happened to me more than once. You're definitely not being unreasonable.

After asking another family member, apparently I am unreasonable to mention it as it might embarrass her. I have animals too and would want to know if I had fleas to deal with

Ouch, YANBU.