**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THE QUESTION OF WHEN AND HOW ANIMAL MOVEMENT IS MOST LIKELY TO INFLUENCE PARASITE LOADS IN RESIDENT ANIMAL HOST SPECIES IS A GLOBAL PROBLEM OF EXCEEDINGLY BROAD RELEVANCE. THIS PROPOSAL TESTS A NEW CONCEPTUAL FRAMEWORK ABOUT HOW FUNDAMENTAL ASPECTS OF ANIMAL MOVEMENT POSE SPECIFIC DISEASE RISKS TO RESIDENT WILDLIFE AND LIVESTOCK POPULATIONS, AND BLENDS ECOLOGICAL AND VETERINARY PERSPECTIVES TO ADVANCE GENERAL UNDERSTANDING OF HOW MOVEMENT SHAPES INFECTIOUS DISEASES. THIS RESEARCH WILL CHARACTERIZE AND QUANTIFY THE ROLE THAT MULTIPLE POTENTIALLY OPPOSING PROCESSES (FOR EXAMPLE, MOVING ANIMALS CAN BRING PARASITES INTO UNINFECTED AREAS, BUT THEY CAN ALSO REMOVE THEM BY FEEDING ON THE PLANTS THAT HOST THESE PARASITES) PLAY IN DIMINISHING OR ENHANCING THE LEVEL OF THREAT THAT MOBILE ANIMALS POSE TO RESIDENT ANIMALS, INCLUDING LIVESTOCK. THIS EFFORT IS SIGNIFICANT BECAUSE ANIMAL MOVEMENT HAS BEEN IMPLICATED IN THE SPREAD OF A NUMBER OF INFECTIOUS DISEASES OF HUMAN AND ANIMAL HEALTH IMPORTANCE, YET THE RULES THAT GOVERN WHEN OR WHERE SUCH OUTCOMES ARE TO BE EXPECTED ARE ALMOST ENTIRELY UNKNOWN. WE WILL CONDUCT THIS WORK IN ONE OF THE FEW GLOBAL ECOSYSTEMS THAT STILL HOSTS A LARGE INTACT ANIMAL MIGRATION (THE SERENGETI ECOSYSTEM) BECAUSE THIS WILL PROVIDE US WITH THE WIDEST POSSIBLEWIDE RANGE OF ANIMAL MOVEMENT SCENARIOS TO STUDY. AS LARGE ANIMAL MIGRATIONS ARE RESTORED IN THE U.S. (FOR EXAMPLE, BISON MIGRATIONS IN THE GREAT PLAINS), WE WILL BE IN A POSITION TO APPLY KNOWLEDGE GAINED IN THE SERENGETI TO UNDERSTAND THE IMPACT OF MOVEMENT ON DISEASE TRANSMISSION IN A WIDE RANGE OF OTHER ECOSYSTEMS.