In the last week or so we have been noticing large numbers of fleas when we go a particular part of the yard. I have lived in this house for 3 years and have NO pets. I was horrified to find the fleas on my feet and legs. Today I have sprinkled lots of Borax around the area. The only ones in the house are what we walked in and couldn't catch. Because I have no pets will they still breed in the house?