Preface

Approximately 20 years ago, the American Association of Veterinary Parasitologists sponsored an issue of the Veterinary Clinics of North America: Food Animal Practice. The issue, edited by Drs. R. P. Herd, H. C. Gibbs, and K. D. Murrell, was entitled “Parasites: Epidemiology and Control” and soon became the standard reference on the epidemiology and control of both ecto- and endoparasites in ruminants and swine. However, much has happened in the intervening years, and it was considered time for an update. When approached, I was thrilled to lead this effort and have learned much. For example, many issues from 20 years ago are still around, the most obvious of which is anthelmintic resistance. What's more, understanding of the basic epidemiology of the gastrointestinal nematodes, to a great extent, comes from information derived from studies conducted 15 to 20 years ago. Whether the repeated use of anthelmintics over this timeframe, changes in management practices, climatic change, or other unidentified processes have altered those patterns has not really been investigated. On the other hand, new ways of looking at this same information have resulted in the exploration of novel parasiticides and fresh approaches to combating anthelmintic resistance. In contrast to the nematodes, great strides have been made in our understanding of other parasitic diseases, some of which we knew little, if anything, about 20 years ago. Most prominent here are many of the protozoal parasites, as evidenced by the increased article length compared with the 1986 edition.

The most important (re)observation I made was how generous the people are with whom we work. I wish to thank all of the authors who contributed their time and energy so that this issue could be produced, many of whom did so despite more pressing worries and I am in their debt. Unfortunately, not all topics from the previous issue could be included in the update. Missing are the swine chapters and information on ruminant trematodes and cestodes. Despite these shortcomings, the hope is that this issue, in the words of Drs. Herd, Gibbs, and Murrell, “… will introduce new concepts to those not yet exposed to them, dispel many old myths, and challenge young research workers to fill in important gaps in our knowledge” [1].