kinds of pests

I was wondering how to get rid of fleas, eggs, et al, from behind the master bathtub.  My cats have access to this area, but I really do not (6 in. x 6 in square max.).  I was thinking of putting a heated flea trap since there is electric. Any other thoughts?  The access to this area is floor level through the master bathroom closet and is almost impossible to get to.

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