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Toxoplasma gondiiの生物学的研究 : 第1報 Toxoplasma gondiiの各種理化学的条件に対する抵抗性に関する実験

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Title: Toxoplasma gondiiの生物学的研究 : 第1報 Toxoplasma gondiiの各種理化学的条件に対する抵抗性に関する実験
Other Titles: Biological Studies on Toxoplasma gondii : I. Examination on the Resistance of Toxoplasma gondii to Physico-Chemical Conditions
Authors: 本村, 一郎
Authors (alternative): Motomura, Ichiro
Issue Date: Dec-1967
Publisher: 長崎大学熱帯医学研究所 / Institute of Tropical Medicine, Nagasaki University
Citation: 熱帯医学 Tropical medicine 9(4). p201-225, 1967
Abstract: Not a few unknown problems are still left undissolved about the biological characters, life cycle and infection route of Toxoplasma gondii, although numbers of papers relating to the parasites have been published. It is really important to devote attention to the study on the survival ability of T. gondii under various physico-chemical circumstances for the purpose of clarifying the infection route of this parasites. Jacobs et al. (1960) reported that the cyst of Beverley strain survived as long as 68 days at 4℃ but lost viability by heating to 50℃ for 30 minutes or 56℃ for 15 minutes. They stated that freezing or desiccation rendered the cysts non-infective. Similar results were reported by Fukazawa et al. (1964). In this experiment, both of RH and Beverley strains of T. gondii were tested on their resistance to osmotic pressure, pH, temperature, desiccation and UV irradiation. Mice used for the inoculation test were of dd weighing 18 to 20g. RH proliferative forms were collected from the infected mice by aspirating the intraperitoneal exsudates with syringes. The pooled exudate was centrifuged at 100 G for 5 minutes to remove the gross particles and the supernatant was recentrifuged at 1500 G for 15 minutes to precipitate the parasites which were subsequently resuspended in saline. The infected mouse brain emulsions were used as the cyst material. Both materials, the saline suspension of RH proliferative forms and the brain emulsion containing the Beverley cysts, were applied to an examination on the survival of T. gondii under some physico-chemical conditions. The presence of live Toxoplasma in the materials was examined by the intraperitoneal inoculation into healthy mice. When proliferative forms or cysts were detected in the peritoneal exudate or the brain of inoculated mice, it was concluded that the parasites inoculated had been still alive in the materials. Hemagglutination test was performed for inquiring whether the infection with the parasites inoculated was in progress. Results obtained were concluded as follows: 1) The proliferative form could survive only within 1 minutes in distilled water. The cyst could survive for 9 days when it was suspended in distilled water together with mouse brain tissue. While, the cysts which were accumulated from the infected mouse brains were destroyed by incubating in distilled water for 16 hours. 2) Both the proliferative form and the cyst could survive for 15 hours in 6% NaCl solution but could not for 15 hours in 15% NaCl solution. 3) At pH 1.2, the proliferative form lost infectivity within 1 hour but the cyst kept it for 22 hours. 4) Both forms lost their viability by heating to 56℃ for 10 minutes. The Beverley cyst survived for 67 days at 2℃ in the refrigerating room of a slaughterhouse but the RH proliferative form did for 11 days. Cysts in the mouse brains and proliferative forms in the mouse livers were destroyed by freezing in a deep freezer of -14℃ for 3 hours. 5) Both forms lost their infectivity to mice by desiccation within 48 hours or by irradiation of UV rays for 5 minutes.
URI: http://hdl.handle.net/10069/4022
ISSN: 03855643
Type: Departmental Bulletin Paper
Appears in Collections:Volume 9, No. 4

Citable URI : http://hdl.handle.net/10069/4022

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