Ugh. My two buns and I just moved into our own apartment, which was sprayed for bugs and carpet cleaned a couple of days before we moved in. I vacuumed as well once I got there, because I found some dog hair on the floor and still get the occasional whiff of “dog smell” from the previous tenant.
Anyway, it’s been over a week and I’ve just discovered fleas on my buns! (Well, on one of them anyway — Pip, the other one, is a Lionhead/Jersey Wooly mix so it’s impossible to see on him, haha.) Not a lot, just one or two, and the buns don’t seem distressed, just irritated. They are both shedding right now so I didn’t think anything of their frequent grooming and scratching until I saw the flea on Prim’s neck yesterday.
I talked to my vet and she told me to use Advantage II for small cats, 0.4ml dose. My vet has 20+ years of experience with rabbits and was recommended to me by a local HRS educator, so I trust her judgment, but I wonder if she meant to say Advantage II for kittens, because my buns are both only a little over 4 lbs each and the small cat dosage is for cats 5-9lbs. Has anyone used the Advantage II small cat formula with buns under 5 lbs?
Also, is there anything else I can do to get rid of the fleas? Unfortunately we are in a studio apartment so I can’t move the buns to another room in order to put spray or powder down in the carpet, and since they have been extremely stressed by the move I really don’t want to put them through any further disturbance if I can avoid it.
Thoughts? Suggestions? I’ve never dealt with fleas before so all help is appreciated! 
ETA: Also, I live in the Southeastern United States (Georgia, to be precise). Does anyone know of any cases of myxomatosis here? I know there were some recent outbreaks on the west coast but I haven’t found any info about this region. It terrifies me to think that as simple an annoyance as the flea could potentially transmit a deadly disease to my buns, especially since the vaccine is not available here!!! My buns are both only a little over a year old and one is prone to health issues, so I’m now way more stressed about this flea issue than I was before I started thinking about the myxo possibility.