土壌内鉤仔虫の回収法とその生存に及ぼす諸要因の検討
スポンサーリンク
概要
- 論文の詳細を見る
Experiments were carried out to evaluate factors affecting the recovery of hookworm larvae from earth by means of a modified Baermann's method. Using the same apparatus, experiments were also carried out to study the effect of temperature, humidity and character of earth on their survival. The following observations were made: 1. Of all the factors involved, temperature of earth has the largest effect on the rate of recovery of hookworm larvae by Baermann's method. It seems that the optimal temperature for recovery of the larvae of Necator americanus and Ancylostoma duodenale ranges from about 30° to 35℃ or 40℃. 2. To stimulate the action of hookworm larvae by placing them in earth with a temperature higher than that of the environment to which they have previously been accustomed, seems to be effective in achieving a high rate of their recovery. 3. The rates of recovery of the larvae of N. americanus and A. duodenale from clay earth were lower than those from sandy earth. 4. Nearly all the larvae of N. americanus and A. duodenale, if placed in 50 gm. of earth forming alayer of less than 1cm. thick, may be recovered within 30 minutes under favorable conditions. 5. The rate of recovery of the larvae of N. americanus from 200 gm. of earth was lower than that from 50 to 100 gm. of earth. Further studies will be needed on the amount of earth to be used, the size of a separating apparatus, and the thickness of the layer of earth in a sieve, in order to develop a better method of recovery. 6. The larvae of both N. americanus and A. duodenale survived 28 days in wet earth with temperatures of 20℃ and 30℃. This indicates that the optimal temperature for their survival in earth ranges from 20° to 30℃. 7. In wet earth with a temperature of zero to 2℃, the power of resistance of the larvae of N. americanus was far weaker than that of the larvae of A. duodenale. 8. The larvae of N. americanus were less resistant to dryness of earth than those of A. duodenale.9. The larvae of A. duodenale, when placed in sandy earth with a temperature of 30℃ and a humidity of 5 %, survived fairly long. If humidity fell and the earth became wholly free from moisture, they would perish in a short apace of time. 10. The rates of recovery of the larvae of N. americanus and A. duodenale from wet clay earth were lower than those from wet sandy earth. The cause for this difference in the rate seems to lie not so much in the nature of earth as in the method of experiments used or other circumstances.
- 千葉大学の論文