Species of the genus are found worldwide in warm regions.[2] They parasitize cats, dogs, and wild carnivores, while coprophagous beetles, reptiles, and small mammals serve as intermediary hosts.[2][3] Two hosts (Eurasian lynx) of endangered species were recently found in Iran and the flatworm genus Joyeuxiella was proved to be the reason for death. Unlike some other related species, their egg sacs contain only one egg.[2]