Protozoan Parasites of Domestic Animals and of Man

Protozoa are among the most important causes of disease in both man and domestic animals. Malaria, while often believed to be no longer important in the United States, still holds first place among the world's human diseases. Amebic dysentery, trypanosomiasis, and leishmaniasis are among other important protozan diseases of man. Domestic animals suffer heavy losses from coccidiosis, trypanosomiasis, trichomoniasis, and many others. At one time it was thought that man and the lower animals each had their own protozoan parasites and their own diseases and that each of these moved in its own separate sphere. We know now that this is not true. As our knowledge has grown, we have come to recognize a growing number of parasites and diseases which are shared by man and lower animals. As a consequence, the zoonoses—diseases common to man and animals—are receiving more and more attention, and domestic and wild animals are being