Additional 10 cases of human infestation with hard ticks in Toyama Prefecture, Japan, with two cases by Amblyomma testudinarium (Acari: Ixodidae)

Abstract

We report here total ten human cases suffering from hard tick (Acari: Ixodidae) infestations in Toyama Prefecture located in the main island of Japan (Honshu) from 2010 to 2015. The causative tick species are as follows: Ixodes monospinosus (3 cases), Amblyomma testudinarium (2 cases), Haemaphysalis flava (1 case), H. japonica (1 case), H. longicornis (1 case), I. ovatus (1 case), and I. persulcatus (1 case). Of these, the one case with H. japonica tick infestation is considered to happen in Hokkaido, not in Toyama, Japan. The two by A. testudinarium tick infestations are re-emerging cases after a long absence since the first case reported in 1976 in Toyama Prefecture. It is speculated that the new two cases might be related to the expansion and the colonization of Japanese wild boar Sus scrofa, a host of A. testudinarium. Finally, two episodes of three patients with I. monospinosus tick infestation are suspected to occur during a school trip to Mt. Tateyama in Toyama Prefecture. The collected data remind us of a risk of hard tick infestations in mountain areas and we should pay careful attention to prevent and treat this infestation.