縮小絛蟲Hymenolepis diminuta (RUDOLPHI)の發育史に關する研究, 特に鼠蚤との關係に就て

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1) We have studied on the life-history of Hymenolepis diminuta (RUDOLPHI), especially on the relation between this tapeworm and rat-fleas. The tapeworm commonly infests house-rats and is often found in human bodies, being rather widely distributed in this country. 2) Experimental studies were carried out on four common species of rat-fleas, Ceratophyllus anisus ROTHSCHILD, Ceratophyllus fasciatus BOSC, Leptopsylla musculi (DEGES), and Xenopsylla cheopis (ROTHSCHILD). regarding their suitability as intermediate hosts for this tapeworm. To determine this. we have first infected larvae of these four species of rat-fleas by feeding them on the eggs of the tapeworm mixed with their food, and then traced the development of the embryos, e.i. oncospheres of the tapeworm which are enclosed within the eggs, in the body of the larvae of the flea. The oncospheres of the tapeworm were observed to develop completely into the cysticercoids in the body of each species of the rat-fleas independently of the metamorphosis of the insect hosts. Thus we have been able to ascertain that each of the four species of the rat-fleas is the suitable intermediate host for this tapeworm. 3) The development of the oncosphere in the body of the flea is much affected by the atmospheric temperature. At a low temperature as in early spring (March and April) it takes from 22 to 31 days to develop into the cysticercoid, whilst at a high temperature as in late spring and summer (from the middle of May to the end of July) the oncosphere develops into a young cysticercoid in a short duration such as 7 to 10 days, and becomes a mature cysticeroid in from 15 to 20 days, getting the full infectivity for the vertebrate host. 4) It has been observed that the cysticercoid developed in the body of the rat-flea is almost the same in its size, form and structure as that which performed its metamorphosis in the body of early stages of the corn-moth. 5) When the larvae of the four species of the rat-fleas were fed experimentally on the eggs of the tapeworm, infestation usually occured in a certain number of the flealarvae. The percentage of the infected specimens among experimented larvae in each species of the rat-fleas was as follows: 23 (30.66%) specimens infected among 75 experimented larvae in Ceratophyllus anisus; 172 (27.69%) among 621 larvae in Ceratophyllus fasciatus; 88 (27.85%) among 316 larvae in Leptopsylla musculi; 4 (0.59%) among 673 larvae in Xenopsylla cheopis. 6) The number of the oncospheres or cysticercoids found in one infected flea varied according to the individual from one or two at least to twenty or more at most. 7) Examinations were made to know in what ratio rat-fleas which are found on living rats would be naturally infected with the cysticercoid of the tapeworm, the result of the examination in each species of the rat fleas being as follows: 6 (2.11%) specimens among 284 examined fleas were naturally infected with the cysticercoids in Ceralophyllus anisus; 11 (1.22%) specimens among 905 examined fleas in Ceratophyllus fasciatus; only one (0.82%) specimen among 122 fleas in Leptopsylla musculi; but none of 98 examined fleas was naturally infected with the cysticercoid in Xenopsylla cheopis. 8) We have also succeeded in infecting albino rats (Rattus norvegicus var. albus) by feeding them on fleas harbouring the cysticercoids developed from the egge which were experimentally given to the larvae of the fleas. The cysticercoid develops gradually in the posterior half of the small intestine of the rat, and reaches maturity 15 days after it was taken by the rat, attaining 21.0-31.5cm in length. From this time we can usually find the eggs of the tapeworm in the faeces of the rat.
社団法人日本動物学会の論文
1936-10-15

縮小絛蟲Hymenolepis diminuta (RUDOLPHI)の發育史に關する研究, 特に鼠蚤との關係に就て

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