In descending order, by date published.
Parasites live in a host from which they obtain food and protection. They may harm but usually do not benefit the host. The word "parasite" is derived from the Latin and Greek languages meaning, in general, "one who eats at the table of another." It is said that a "good" parasite does not overtly harm or kill its host. It is theoretically possible that a more benign parasite (e.g. Gasterophilus spp.) is much "older in eons of time" and it and its host have adjusted better to each other than a conceivably "newer" parasite (e.g. Strongylus spp.) which may be more harmful to its host.
5/3/2012 (major revision)
Authors: Sharon Tolliver
Now that veterinarians and researchers are beginning to accept the pathological consequences that can be caused by cyathostomes (small strongyles), more and more researchers want to learn to identify them. Fortunately, for those just learning, the reality is that they will probably see fewer than one-third of the 33 species. Additionally, these species are the most prevalent and in the greatest numbers; consequently, they are the most dangerous to equids. Once a person is familiar with these, a rare species will "stick out like a sore thumb." The fact that a species is so different will be noted and its characteristics easily remembered.
The present bulletin focuses mainly on drug-resistant species (small strongyles and ascarids) of internal parasites of the horse with emphasis on historic research. Some discussion is presented also of research at UK on the sheep "barber pole" stomach worm (Haemonchus contortus) which has a historic role in drug resistance.