Which nematode is typically free-living but can cause opportunistic dermatitis infections in animals?

The correct identification of Rhabditis as a nematode that is typically free-living and can cause opportunistic dermatitis infections in animals is rooted in its biology and interaction with host organisms. Rhabditis species are predominantly found in soil and decaying organic matter, where they exist in a free-living form. Under certain conditions, such as when host defenses are compromised or when there are alterations in the environment, Rhabditis can transition to a parasitic lifestyle, leading to infections in animals.

These nematodes are known to exploit situations where the immune system is weakened or where there is a breach in the skin barrier, consequently leading to dermatitis. This opportunistic behavior is a hallmark of their adaptation, as they can switch from living saprophytically to establishing parasitic relationships under favorable conditions.

The other nematodes listed have different ecological roles and pathogenic profiles. For instance, Necator americanus is primarily a hookworm that infects the intestines of its hosts, while Rhabditella, although related, does not typically associate with causing dermatitis infections. Strongyloides has a more complex life cycle and is primarily known for its ability to cause strongyloidiasis but does not fit the profile of being primarily