Nothing in Airbnb's terms precludes a host from using an unoriginal title for their listing. Fortunately for you, the title is not really the thing that brings guests to your listing and makes them choose to stay with you - it's your location, amenities, photos, and great reviews. You can change your listing's title every week without significantly affecting your brand or your guests' perceptions of it. Case in point: I've stayed in dozens of Airbnb's and I can't remember a single one of their listing titles. Actually, you might find it to your advantage to change the name occasionally - for example, empasizing the warm and cozy nature of your property in winter while highlighting the outdoor features in summer. "Mi Casa Su Casa" may nicely convey your hospitality style, but the same can be said of thousands of hosts out there.
If you do feel that another host might be trying to piggyback on your listing or scam their potential guests, keep an eye on their profile for copies of your photos or other potentially fraudulent details. If you find evidence that the host is misrepresenting their property as yours, then you should report them to Airbnb.