The impact of river and mountainous terrain on the spread of Formosan ferret-badger (Melogale moschata subaurantiaca) rabies in Taiwan

Since the initial epizootic of the Formosan ferret-badger (FFB) rabies outbroke in 2013, the enzootic area of the FFB rabies has always been limited to six counties and three cities in Taiwan. These six counties and three cities, from north to south, are Taichung City, Nantou County, Yunlin County, Chiayi County, Tainan City, Kaohsiung City, Hualien County, Taitung County, and Pingtung County. They are located south of the Daan River and the Heping River, the latter is on the east side of the Daan River. In January 2023, ten years after 2013, under the annual Surveillance Program for the Detection of the FFB rabies instituted by the Animal and Plant Health Inspection Agency (APHIA), Ministry of Agriculture, it was found that the FFB rabies virus had spread across the Daan River and entered Miaoli County, which is located in the north side of the Daan River. The previously naïve populations of FFBs in Miaoli County were infected; therefore, another initial massive epizootic of the FFB rabies cannot be ruled out in areas north of the Daan River and the Heping River in the future.