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OBJECT AND SCOPE OF THIS AND RELATED PROJECTS

The primary objective of Volume I of this series of studies is to present our research on Sudanese ticks, including a critical survey of published worldwide information concerning each species. This has been attempted with reference to: (a) distribution in the Sudan and elsewhere, (b) hosts, (c) biology, and (d) identification. The secondary objective is to provide a suitable background for subsequent volumes presently in preparation. These studies will include all economically important tick species of Africa and all diseases and injuries associated with them.

The present report is intended to serve the tyro and specialist alike, and should provide a sound source of information for those who compile textbooks and review literature. Special attention is invited to the introductory paragraphs in section IV, pages 43 to 47, in which presentation methods and handling of data are elucidated, and to the fact that mention of disease relations herein are merely cross-referencing for subsequent volumes.

It should be stressed that most tick species of known or potential medical or veterinary importance of the Ethiopian Faunal Region (see Figure 1) are found in the Sudan and are treated in the present report. Those few species that do not occur in the Sudan will be treated in a forthcoming volume, entitled "The Economically Important Ticks of Africa." Therefore, pertinent facts concerning all known species of medical and veterinary importance of continental Africa # be included in these two reports.TATso included in the forthcoming volume will be maps of the distribution of each species in the Sudan, as well as in other African regions and elsewhere in the world. Subsequent volumes will be entitled: "Human Tick-Borne Diseases and Injuries in the Ethiopian Faunal Region” and "The Biological Relationships of African Ticks and Veterinary Diseases." Since a year or more will probably elapse between the publication of each volume, additional material concerning species previously treated will be presented in each new section in an effort to bring the pertinent information up-to-date.

The primary purpose of the report on veterinary diseases, mentioned above, is to present the biological relationships of ticks to these diseases in order to provide a better working knowledge for basic research in human diseases. It is also intended that this section will be of use to veterinarians in the area concerned.

Possibly one of the greatest general criticisms of contemporary literature on African ticks is that the reader obtains the impression that specialists" knowledge is usually more or less complete with respect to identification, biology, hosts, and distribution. When first considering the study of African ticks, I was told by several scientists that these parasites were so well known and so easily identified that there would be little to do that could not be accomplished in short order! Quite the contrary proved to be true; and it was soon realized how much specialized and practical information on African ticks is lacking. The best expectation for this undertaking is that the numerous indications for existing queries, problems, and lacunae in our information on African ticks will stimulate readers to seek out additional data. It is also hoped that this work will provide a useful body of information for authors of textbooks and teaching manuals. Towards these ends, every effort has been made to present and review data as correctly as possible. Should errors occur, it will be appreciated if readers call them to my attention for inclusion in errata in subsequent volumes.

HISTORY OF THIS PROJECT

This project commenced in 1948 with a small tick collection made mostly in Equatoria Province of the Sudan, and also in other parts of East Africa and Madagascar. I was, at that time, a member of the Naval Medical Science Group accompanying the University of California African Expedition. Subsequently, between October 1949 and April 1950, when assigned by NAMRU-3 to Torit, in Equatoria Province, for study of elephant shrew malaria (Hoogstraal, Huff, and Lawless 1950, Hoogstraal 1950, 1951, 1953A, 1955A), a larger tick collection was accumulated. This was assembled, however, chiefly as an avocational pursuit.

Upon the return of our party to Cairo in 1950, study of these collections commenced. During the course of the literature review necessary for this work, it became apparent that much data was so scattered as to be of little use, that a certain amount of earlier inaccuracy or vagueness was frequently uncritically quoted and reported, and that our specimen material contributed no little amount of new information on African ticks. Interestingly enough, though much new data were obtained, only two completely undescribed species and a few previously erroneously recognized species were included in the collection. This would indicate that the skeleton of knowledge of East African ticks is rather complete but that the covering body of supporting data is still much in need of development.

In the light of these observations, it was decided to add a literature survey to the Sudan tick report and to commence the review of African tick-borne diseases. This latter report is an outgrowth of attempts to find details of African tick-borne diseases in current textbooks on medical entomology. Suffice it to say that the study of these textbooks was most disappointing with respect to accuracy, weight of controversial information, and evaluation of important factors in relation to each disease.

In order to make the already-available tick collection more broadly representative of the overall composition of the local tick fauna, a collecting trip in the Sudan was undertaken during December 1951 and January 1952. The Sudan Government collections at Wad Medani were also studied, and additional information on tick distribution in the Sudan was incorporated into the present report. At the same time, the Sudan Veterinary Service requested its staff in various Provinces to collect and send specimens for determination. These latter collections added valuable data on distribution of ticks infesting domestic animals, which are often also those most important in relation to human diseases. Subsequently, other collections were also identified for the Sudan National Museum and for Gordon College, Khartoum, and their data recorded.

During the course of these studies, a number of taxonomic problems, background questions, and literature-evaluation uncertainties have arisen. Opinions of specialists in various parts of the world have been widely solicited in order to settle these matters so far as possible.

The magnificent tick collection in the British Museum (Natural History) was studied during the summers of 1951 and 1952 and early in 1955 further to investigate taxonomic problems and to extract pertinent unpublished data (Hoogstraal 1954C). African collections have also been identified for the Chicago Natural History Museum, Museum of Comparative Zo'51ogy at Harvard University, and several other institutions. During the summer of 1952, visits were made to the following institutions for the purpose of checking and acquiring information: Museum of Comparative Zoölogy, United States National Museum, and Rocky Mountain Laboratory at Hamilton, Montana.

Another visit to Equatoria, Bahr El Ghazal, Blue Nile, and Khartoum Provinces was made in November and December of 1952 to search for Ornithodoros ticks and to collect living ticks and human blood sera for comparative virus and rickettsial investigations. In February of 1953, I visited the Sudan Veterinary Service's "Jur Narrows game eviction project" in the Galual-Nyang forest area of Bahr El Ghazal Province and obtained a number of valuable records from this area.

During the winter of 1954-1955, I was fortunate to be able to visit a number of institutions for final studies and conferences in connection with the preparation of this report. Chief among these were: The Rocky Mountain Laboratory; Camp Dietrick, Maryland; Animal Parasite Laboratory of the United States Department of Agriculture at Beltsville; Zoology Department of the University of Maryland; United States National Museum; Bureau of Medicine and Surgery of the Navy Department at Washington, D.C.; British Museum (Natural History); London School of Hygiene and Tropical Medicine; King's College of the University of London; and Tring Museum.

At various times throughout this period of study I have been privileged by the United States Navy to visit other areas for obtaining comparative materials for this study. In addition to extensive searching in Egypt, including Sinai and the Sudan frontier, trips for this purpose have been undertaken in Kenya, Uganda, Tanganyika, Belgian Congo, Eritrea, French Somaliland, Yemen, and Turkey. A U.S. Navy-Smithsonian Institution collaborative project is at present underway in Libya.

A brief preliminary report of this work has been published (Hoogstraal 1954B) and three new species found in the Sudan during this survey have been described (Hoogstraal 1955B, 1956A, ).

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I am happy to express appreciation to Captain C. B. Galloway (MC) USN, Director of U.S. Naval Medical Research Unit No. 3, and to his predecessors, Captain A. R. Higgins (MC) USN, and Rear Admiral J. J. Sapero (MC) USN (Ret.) for their constant encouragement in the preparation of this report.

For much assistance I am also indebted to my first mentor in the study of ticks, Dr. J. Bequaert of the Museum of Comparative Zoëlogy, Harvard University.

The helpful hand of Dr. Gertrud Theiler of Onderstepoort, Transvaal, appears on many pages of this report. In many otherwise unmentioned ways she has been so cooperative that it is difficult to express appreciation in sufficiently glowing terms. Dr. Theiler has identified all the immature specimens listed in this report and has checked many adult specimens of difficult or questionable species. Many of the discussions of species in this report reflect conclusions Dr. Theiler has drawn from years of study and her generous permission to utilize unpublished results of this experience.

Special attention should also be called to the wholehearted cooperation of Mr. Glen M. Kohls of the Rocky Mountain Laboratory who since the beginning of this work has spent many hours in reviewing this manuscript and offering valuable comments. During two periods of study at his laboratory, Mr. Kohls provided me with every assistance.

To Mr. David J. Lewis, formerly of Wad Medani, Sudan, I am indebted for his graciousness in putting the Sudan Government collections at my disposal and providing me with facilities for study while visiting there. Dr. R. Kirk, formerly Director, Stack Medical Research Laboratories, Khartoum, Dr. J. F. E. Bloss, formerly Assistant Director, Sudan Medical Service, and numerous other persons in the Sudan have been most generous in providing assistance of various kinds for work in that country. I am especially grateful to Mr. J. T. R. Evans, formerly Director, Sudan

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