Preface 



The importance of protozoan parasites as causes of disease in domestic animals is 

 well recognized, yet the literature on them is still widely scattered and the books now 

 available provide little more than an introduction to the subject. The present book was 

 written to serve as a text and reference work for veterinarians, protozoologists, para- 

 sitologists, zoologists and also for physicians. As our knowledge of the relations be- 

 tween human and animal parasites has increased, the list has also increased of parasites 

 which were once thought to be confined to domestic and wild animals but which are now 

 known to occur also in man. The area of overlap between the fields of human and animal 

 disease is becoming continually greater, and the zoonoses are receiving more and more 

 attention. For this reason, the protozoan parasites of man are included in this book, 

 and their relations to those of lower animals are indicated. 



When this book was begun, it was intended to be a revision of the pioneering 

 Veterinary Protozoology by the late Banner Bill Morgan and the late Philip A. Hawkins, 

 the second edition of which was published in 1952. However, it soon became apparent 

 that far more than this was necessary, and the result has been an entirely new book. 



It is planned to follow this volume with others on veterinary helminthology and en- 

 tomology. The first chapter, therefore, deals with the general principles of parasitology, 

 while the second is an introduction to protozoology. The different groups of protozoa are 

 discussed in the succeeding chapters, and the final chapter deals with laboratory diag- 

 nostic technics. This systematic organization based on parasite groups is used rather 

 than one based on host animals because it is more efficient, avoids repetition, and makes 

 the subject easier to present and to understand. However, it is also useful to know which 

 parasites one can expect to find in each host. Lists of parasites by host have therefore 

 been prepared and are incorporated in the index. E. A. Benbrook (1958. Outline of 

 parasites reported for domesticated animals in North America. 5th ed. Iowa State Univ. 

 Press) has listed the parasites both by host and by location in the host. 



The world today is too small to permit a provincial approach to parasitism and 

 disease. Katanga and Uttar Pradesh, Kazakhstan and Luzon are only a step from New 

 York and San Francisco, and their problems and their diseases are becoming more and 

 more our concern. The scope of this book, therefore, is world-wide, and parasites are 

 discussed regardless of where they occur. However, major attention is given to the 

 parasites of those domestic animals which occur in the temperate zones, and relatively 

 little is included on parasites of animals like the elephant, camel, llama, reindeer and 

 yak, even tho they are important domestic animals in some regions. 



When C. M. Wenyon wrote his classic Protozoology in 1926, he remarked that one 

 of his chief difficulties had been that hardly a week passed without the publication of some 

 paper of importance; that difficulty is far greater today than it was then. The number of 

 published papers has been increasing exponentially, and there is no sign that the loga- 

 rithmic phase of the curve is near its end. Even if one tries to read the current journals 

 faithfully and to use the abstract journals assiduously, important papers may escape his 

 notice. I am sure that some have escaped mine, and I should appreciate having them 

 called to my attention. In addition, to help me in preparing future editions, I should ap- 

 preciate receiving reprints of pertinent papers. 



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