The flea's diminutive size has made it a global symbol of insignificance. But as carriers of typhus and tapeworms – not to mention bubonic plague – fleas will not be ignored.
One of the original subjects of microscopic examination (early microscopes were called "flea glasses"), fleas can now boast of nearly 3,000 identified species. The most commonly encountered is the cat flea, Ctenocephalides Felis, but despite its name, it is broad-minded with respect to hosts and will happily affix itself to dogs – as well as their best friends!
If you encounter a flea, thorough vacuuming, twice a day for several weeks, is recommended. A single flea can lay hundreds of eggs, so you don't want to miss any. (And if you do, call for help: professional exterminators should be able to handle the problem.)
Of course, fleas are hardly all-work-and-no-play: they have the noted abilities to jump hundreds of times their own height and carry loads hundreds of times their own weight. These remarkable skills probably account for the creation of circuses designed to highlight other remarkable flea-talents such as playing in an orchestra, dancing, juggling, fencing, and a variety of other diverting activities. So if all else fails, send in the clowns.