My wife works in the veterinary supply industry, and provides several  
different products for pets to get insects, including ticks, off of  
the animal. One of the downsides is that these do not work  
instantaneously... that is, the tick gets on a pet, it comes into  
your house, and the tick then decides it has chosen the wrong animal  
and gets off, only to look for another host in the house. Using one  
of these products, even 'effectively,' does not mean your pet can't  
bring ticks into the home.

Mark Schilling
Kent Island, MD