Environmental-medical and sanitary-zoological investigation on the land leech biohazard spreading at the southern area of Boso Peninsula.
Grant-in-Aid for General Scientific Research (C)
|Allocation Type||Single-year Grants|
|Research Institution||The Jikei University School of Medicine|
YOSHIBA Shigeo The Jikei University School of Medicine, Professor, 医学部, 教授 (90056549)
|Project Period (FY)
1990 – 1991
Completed(Fiscal Year 1991)
|Budget Amount *help
¥1,600,000 (Direct Cost : ¥1,600,000)
Fiscal Year 1991 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1990 : ¥800,000 (Direct Cost : ¥800,000)
|Keywords||land leech / Haemadipsa zeylanica japonica, Whitman, 1886 / land leech biohazard / anti-land leech antibody / explosive propagation of land leech / immunological thinning out / ニホンヤナビル / ヤマビルの異常大発生|
1. As the result of continuous fixed point investigation on the land leech population, their active period prolonged toward mid winter, and several individuals of the leech were collected even in December and January and they spawned 3 egg masses.
2. As the causes of this explosive occurrence of the land leech, (1)appearance and wandering of deers in the town, (2)scarce existence of natural enemies of the land leech, and(3)weather condition in 1984 that was suitable for the leech propagation were listed.
3. As the natural enemies of the land leech, 4 species of insect were confirmed among 77 species of carnivorous animals tested, but they are hardly useful to practically exterminate the leech because of less chances to meet with the leeches.
4. Symptoms induced by bloodsucking of the leech are local bleeding (caused by prolonged bleeding time and loss of coagulation) lasting for about 1 hour, followed by itching and occasional induration, and the application with plaster and treatment wit
h 1% tannic acid cotton are effectual.
5. Anti-land leech antibody was produced in the blood of bloodsucked humans and mammals and increased with the frequency of bloodsucking. This antibody lightens the local bleeding and kills the leech. These antibody values were detected even in cases affected more than 17 years ago by another subspecies of Haemadipsa.
6. It was proven that deers act as if the proper host of the land leech and carry several tens of the leeches on their extremities and that they have a kind of hollowed inflammatory tumors between the 3rd and the 4th toes, within the hollow of the tumors a leech enters.
7. The population of the land leech is controlled immmunologically by killing effect of the antibody.
8. Some ground walking birds will be safe carrier of the land leech because they are prefered by the leech but hardly produce anti-land leech antibody.
9. Hotwater extract of tobacco and nicotin sulfate are effectual for field extermination of the leech and salt powder or ashes of tobacco and mosquito coil are fitted to removal of the leech on the skin, and these substances are lethal to the leech. Less
Research Output (22results)