Additional Case Studies of Human Infestation with Hard Tick (Acarina : Ixodidae) Found in Okayama Prefecture, Japan
Two new cases of human infestation with hard tick (Acarina: Ixodidae) from Okayama Prefecture, Japan are further reported. Case 1 : On August 20th., 1996, hard tick bite was found on the skin surface of left occipital region of a 61-year-old woman living in Bisei-Cho, Oda-Gun, Okayama Prefecture, Japan. The tick body removed from the patient measured 4.6 mm in length and 3.5 mm in maximum width. Case 2: On August 4th., 1997, hard tick bite was found on the skin surface of left nipple of a 64-year-old woman residing in Kurashiki City, Okayama Prefecture, Japan. The tick body collected from the patient measured 5.2 mm in length, 6.4 mm in maximum width and about 5.2 mm in height. On acarological observation, the ticks found from those 2 patients were identified as adult females of Haemaphysalis longicornis Neumann, 1901 based on morphological characteristics of capitulum, scutum, internal and external spurs on coxae, genital aperture and spiracular plates. The tick bites seemed to have happened on hilly area in Case 1, while the site of bite was not clear in Case 2. No essential change of systemic symptoms other than tick bite wounds was recognized in those 2 patients. To our best knowledge, the present report constitutes the 29th and 30th findings of human infestation with hard tick in Okayama Prefecture, Japan.