Eggs of fleas can stay unhatched for a very long time. The vibration
from vacuuming can cause them to hatch. You can get chemicals that
are safe to spray on your furniture. carpet, and other infected
areas.

I had a dog and 3 cats that I found dropped off in our area. I took
them in and got fleas really bad.

I went to my local do it yourself pest control company and used what
they recommended.; I haven't had fleas in 3 years. Here is a link
to some informaiton for it.

http://www.bugsaway.com/fleas/

You can buy from them to have it shipped.