Modeling the Asian Longhorned Tick (Acari: Ixodidae) Suitable Habitat in North America.

Asian longhorned or bush tick (Haemaphysalis longicornis Neumann) is a vector species of considerable medical and veterinary importance within its native range in East Asia, and in introduced areas of Australia and Oceania. Recently, this tick species was detected in several regions of the United States. This study aimed at modeling areas suitable for H. longicornis in North America using maximum entropy distribution modeling or Maxent. Occurrence records of H. longicornis within its present range were obtained from published literature. The Maxent model contained a small number of a priori climatic and ecological variables. Annual temperature, precipitation, and ecological zones were found the most important in creating sensitive and specific model (success rate = 91.8%) that had a good fit to the existing data. The model predicted suitable H. longicornis habitat in most of eastern North America from southern Canada to the Gulf Coast, and in a small temperate area on the West Coast. Coastal areas were among the highest ranked suitable habitat. Another highly suitable region was identified in mid-western and southern United States where Heartland virus transmission takes place. This finding is of concern, since H. longicornis ticks vector a closely related virus in East Asia. Delineation of areas suitable for H. longicornis can facilitate detection, prepare public health authorities, and inform the general public about this potentially pestiferous and medically important species.