Correspondence: Tsutomu Takeuchi
Qi Hong Ye*
Seiki Kobayashi
Tatsushi Fujiwara
Tsutomu Takeuchi
Department of Tropical Medicine and Parasitology, School of Medicine, Keio UNiversity, Shinjuku-ku, Tokyo 160, Japan.

*ShengYang anti-Epidemic and Sanitary Station, Hung Gu District, ShengYang, China.

Shiro Nozawa
Hiroyuki Ohta
Kazunari Kiguchi
Department of Obstetrics and Gynecology, School of Medicine, Keio University, Shinjuku-ku, Tokyo 160, Japan.

Ryutaro tojo
Tojo Woman's Clinic, Konan-ku, Yokohama 233, Japan.

Jun-ichi Kobayashi
Division of Obstetrics and Gynecology, Saiseikai Kanagawa Hospital, Kanagawa-ku, Yokohama 221, Japan.

Ki-ichiro Sumi
Division of Obstetrics and Gynecology, Nippon Steel Hospital, Kawasaki-ku, Kawasaki 210, Japan.

Akihiko Yano
Department of Medical Zoology, School of Medicine, Nagasaki University, Nagasaki 852, Japan.