No fleas are known or suspected to be threatened with extinction, although it is likely that at least some threatened species will be revealed as research progresses.
Similarly, none is known or suspected to have become extinct in recent years.
Some fleas are very closely associated with a particular host and are never found elsewhere. In these cases it is possible that if the host becomes extinct, so will the flea that depends upon it.
However, many species probably disappear before the status of their populations has been assessed, or even before they are known to science, and therefore they go unrecorded.