弱毒豚コレラウイルス宮城株について

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It has been believed for a long time, in Japan, that the hog cholera virus is so highlyvirulennt, and the pigs so susceptible to it, that in those pigs affected it always takes anacute course, the animals dying from the disease at the rate of 100%. Therefore, it hasbeen very easy to diagnose the disease from the view points of epizootics and pathologicalfindings.In 1956, however, a less virulent strain of hog cholera virus appeared in Watari-machi,in the northern part of Japan. The epizootics were not so severe and the symptoms weremuch different from those of the usual cases, That is, altho some pigs died after showingmarked symptoms, others survived after showirng only slight febril reaction. Since therehad previously been no record of cases recovering after revealing the symptoms of hogcholera, in Japan, the authors at first thought that this disease might rnot be caused by thehog cholera virus. The authors, however, could demonstrate the virus recovered fromfour pigs affected irn the field, and identified it as hog cholera virus from the view pointsof hematological F-ndings, experimental infection of susceptible pigs, hisLopatIto1ogicalfindings, and immunization tests.The details of these data are reported in the following.1) Experimental infection and identification of the causal agent.As the inoculums for the trttnsrnission of this disease, spleen were removed fronn thediseased pigs, No. 1 and No. 5, and the livers from No. 3 and 1Jo, 4. Ten percent sus-pensions with saline were nxade from these organs, respectivc;ly, and each orte, after testingsterility, was inoculated stubcutaneously into each of the susceptiole pigs.Each pig iruoculated with the material of No. l, No. 4 or No. 5 survied after slxowirtgonly slight febril reaction, and all of them resisted strictly, against the challenge, withoutany symptoms, which was carried out 3 weeks later, wich 10,ODD MUD of the virulentstrain ALD of hog clnolera virus.A pig, however, inoculated with the material of No. 3 showed a high fever anddifficTherefore, it may be said that this pig might have survived if the simultaneous infectionof Pasteurella multocida had not occurred.The infection of M)?xovirus parainfluenzae 1, which causes slight reaction similar tothose of hog cholera, was discounted b)x mearns of the isolation of the virus and throughhaernagglutination irnhibition tests wich serum.From the results merttioned above, it can be said that the causal agent of this diseaseis a weak virulent strairn of hog cholera virus, and the authors narrned it strain "IVIiyagi".2) Serial passage of strairu " IVIiyagi".Strain "Miyagi" was passaged, serially, through susceptircle pigs, and some of themsurvived, but the otlners died of hog cholera. Some of the latter were infected simultan-eously with some other bacteria.3) Virus titer of strain " lV1iyagi".The virus Liter of strair? " Miyagi " was measured by using susceptible pigs of the 3rdand 7th ger?erations of serial passage mentioned above. Both Liters were of 10- and atleast by the 7tlx generation the increase of virulence was rtot observed, while two otherwealc virulent strains, obtained from insufficiemxtly inactivated crystal violet vaccine,recovered their virulemce at tI?e 2nd or 4th oeneration.54) Laternt infection by strain " lV[iyagi".Pigs inoculated with 1 1111 of TO dilution of strain " Miyagi " showed subclinicalinfection and this latent infection was checked by mean-ns of a later chatter-ge with virulentstrain AID.These are the first cases of Iatertt infection of hog cholera artificially produced, inJapan.5) Resistance of strain " IVtiyagi" to storage.Strairu "lVIiyagi" showed a strorug resistance to storage at -50C and preserved its acti-vmty for at least a year, while the other weak virulent strain" mentnonccl above, lost itsactivity withirn half a year. Therefore, it is possible to say that Line recovery of virulemreeby serial passage through pigs and the resistance to storage at -50C are different be-tween flue two strains, overt if both straixns are very weak virulent.6)
社団法人日本獣医学会の論文
1961-06-25

弱毒豚コレラウイルス宮城株について

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