Subtropical Disease Control Unit is in Kyushu Research Station which is located in Kagoshima prefecture in Kyushu Island. Our mission is to reduce economic losses in livestock industry through research on arthropod-borne (arbo) viral diseases. Arboviruses such as Akabane, Aino, Chuzan and Ibaraki viruses are transmitted by blood-sucking vectors, Culicoides biting midges, and they cause abortion, stillbirth, premature birth, congenital abnormalities, neurological disorders and febrile illness mainly in cattle. In southernmost areas of Japan, arboviral diseases often cause major economic losses and thus our unit conducts monitoring of arboviruses, characterization of arbovirus isolates, investigation of ecology of Culicoides biting midges, pathological investigation of affected cases, development of diagnostic methods, and epidemiological analyses of arboviral diseases. Our unit also conducts experimental infection of emerging arboviruses to investigate pathogenicity in cattle. We cooperate with prefectural livestock hygiene service centers, epidemiology unit of NIAH and several institutes in neighboring Asian countries in order to accomplish our mission.