Title: Immunity to blood parasites of animals and man
Description: Since the turn of the century, certain parasitic diseases of livestock have frustrated efforts to bring them under control by vaccination techniques; East Coast fever and trypanosomiasis are two such diseases. East Coast fever (ECF) kills a half million cattle annually; and 3 million are killed each year by trypanosomiasis, which is widely spread over tropical Africa. Together, these diseases have closed some 7 million square kilometers of land to livestock grazing-land that might otherwise support an additional 120 million head of cattle. In 1970 W.A. Malmquist of the U.S. Department of Agriculture, in collaboration with K.N. Brown, M.P. Cunningham, and other associates at the East African Veterinary Research Organization in Kenya, succeeded in cultivating in vitro the protozoal organisms responsible for East Coast fever.

This success, obtained utilizing tissue cultures, encouraged a number of organizations to support research on these parasites in an accelerated effort to develop field vaccines. The International Laboratory for Research on Animal Diseases (ILRAD) was created in 1973. Its initial efforts have included the consolidation and advancement of methods for immunization against ECF of cattle and African trypanosomiasis of animals and man. Trypanosomiasis, a disease of much wider range than ECF, is even more intransigent in the face of efforts to control it by immunological techniques, although the recent success of Hirumi and associates at ILRAD in culturing African trypanosomes should afford new approaches to research in this field.

At the same time, veterinarians and researchers from associated disciplines have made steady progress in acquiring the knowledge and developing the methodology that would lead to bringing other livestock diseases, anaplasmosis and babesiosis, under control by vaccination techniques. These two diseases are widespread not only in Africa and Latin America, but in the United States as well. Of equal importance to development in the tropical world are the diseases of man. The drain from diseases such as malaria must be measured not only in terms of mortality and morbidity but also in the loss of productivity that indirectly affects the food supply. Technical and administrative problems have hampered the standard approach to the control of malaria, i.e., antimalarials and insecticide spraying of houses. However, recent advances in malaria research - the cultivation of Plasmodium falciparum by W. Trager and J.

Jensen, and new approaches to vaccination in animals-have raised the hope that a human vaccine may be available in the near future. Certain characteristics of blood-borne parasites are common to the disease process in both animals and man. For example, antigenic variation-a phenomenon that enables the parasite to survive successive waves of antibodies produced by the host-occurs in malaria, babesiosis, and trypanosomiasis. A paramount need has existed to review antigenic variation and other possible mechanisms by which these parasites have been able to counteract the innate resistance and immunological defenses of their hosts.

Accordingly, in September 1975, authorities on diseases of man (Chagas' disease, sleeping sickness, and malaria) and of livestock (trypanosomiasis, ECF, babesiosis, and anaplasmosis) convened at the Rockefeller Foundation Study and Conference Center at Bellagio, Italy, to report on the state of the art and science of immunological approaches for dealing with these diseases. Cellular biologists knowledgeable about antigenic variation per se also participated. The names and institutional affiliations of the participants are listed in Appendix A. Responding to the wishes of the conferees, Dr. Barry Bloom summarized the proceedings in the April 1, 1976, issue of Nature. This volume, an outgrowth of the conference at Bellagio, is based on selected papers that have been revised, expanded, and updated for this publication. It is intended for the use of students, instructors, research workers, and practitioners concerned with blood-borne parasitic diseases.

We hope that the information made available to them in this book will help speed the day when these diseases will be brought under control by immunological techniques similar to those which have long been successful against a wide range of pathogenic viruses and bacteria. Dr. Ian McIntyre, then Dean of the Faculty of Veterinary Medicine, University of Glasgow, Scotland, bore major responsibility in organizing the Conference. His own group of associates has been especially active in research on trypano-tolerant cattle of West Africa and on the pathology of trypanosomiasis.
Subjects: Vaccination, Medical parasitology, Vaccination of animals, Congresses, Veterinary parasitology, Veterinary, Antigens, Immunization, Parasitic diseases, Animal Parasitic Diseases, Prevention & control, Immunological aspects