Experiments were carried out to clarify the state of infection among bitches and their litters. Mites after their exposure to natural surroundings were tested for biological characters and infectivity. In addition, investigation was made to determine whether indirect contagion occurred or not. 1) Of 7 dams of the affected dogs examined, 6 were found infested with mites, though they were apparently healtht. Of 59 puppies given birth from them, 38 were positive and 10, born from uninfected dams, were negative, and the other 11 could not be examined. In 30 young born from 5 affected dams, mites were found without exception. In 9 cured dams with no clinical signs left, mites were found in follicles of the skin for about two years. So it is considered that the highest opportunity of infection might be in the suckling period when there are close relatoins between dam and puppy. Bitches showing no signs of disease might be the most significant as carriers. 2) Mites separated trom hair follicles showed a movement continually till death under the themopactic zone. Inductivity of mite movement by carbon dioxide was not remarkable, as Ixodes mites were found lying in wait for new hosts. Mites which had fallen on the floor of the kennel suffered the influence of such environmental factors as drought and putrefaction of media and died in a few days. Though mites themselves were able to survive at low temperature and high humidity for a long time, they had no ability of infection under such conditions. For these reason, it was concluded that indirect contagion of mites scarcely occurred.
The effect of washing of milk bottles in the milk plant was examined chemically by the method reported by Fujiwara et al. for the test of fat and amino acid remaining stuck to washed utensils for eating and drinking. This method, however, was modified in some points from the results of preliminary experiments. The concentration of alcohol used for dissolution of fat-soluble dye was 70 per cent, instead of 95 to 98 per cent in the original method. The residual fat was acted upon by the dye solution for 3 minutes, instead of 5 minutes. The residual dye present after the action of the dye solution was removed by washing with 40 per cent alcohol followed by a step of the original method to cleanse with water for a minute. Two to four samples were collected at random from 8 milk plants in Tokyo. They were milk bottles after washing. When subjected to tests for the effect of washing, they were found to have residual fat and amino acid adhering to them, without exception. The quantities of these residual substances, however, were so small that, judging from the situation of bottle washing in the milk plant, they might be tolerated with an exception of a few samples. The results of these tests suggest that the method of chemical test adopted in the present investigation may be available for judgment of the effect of washing of milk bottles.
In March, 1962, YOSHIMURAet al. discovered an outbreak of infectious laryngotracheitis in Osaka Prefecture. This disease had never been reported in Japan for the past twenty-five years. Since then it has been confirmed that the disease is prevalent in Osaka and its neighborhood. For the purpose of making a rapid diagnosis, ARMSTRONGs'Sm ear technique for the examination of specific intranuclear inclusions was carried out without satisfactory results. Better results were obtained with SCHAUDINN'S method of sublimate alcohol fixation (addition of 5% of acetic acid) which had been applied to wet-smears of tracheal-mucosa scrapings, and the conventional hemetoxylin-eosin staining. Forty-three experimental and 23 spontaneous case were examined by this method. When the conventional paraffin sections were compared, hardly any difference existed between both methods mentioned above. Inclusion bodies were observed in the experimental cases from 2 to 6 days after the inoculation, and then disappeared in the convalescent cases.
A total of 141 strains of Escherichia coli isolated from diseased swine were examined for susceptibility for 14 kinds of anti-microbial agents in vitro by using the disk and the tube methods In the disk method, high susceptibility was shown by more than 95 per cent of these strains for chloramphenicol (CM) and kanamycin (KM), by about 75 per cent for streptomycin (SM) and chlortetracycline (CL), and by about 60 per cent for tetracycline (TC) moderate susceptibility was displayed by about 20 per cent of the strains for SM and CL. About 15 per cent of the strains exhibited moderate or high susceptibility for three sulfa drugs. Sixty-four per cent of the 141 strains were classified into eight patterns of susceptibility. The multiple-drug-resistant strain was not found In the tube method, about 50 and about 90 per cent of the strains manifested high and moderate susceptibility for furazolidone (FZ), respectively. Susceptibility for furaltadone (FT) was low. More than 90 per cent of the strains revealed high susceptibility for CM, neomycin (NM), and neo-penicolimycin (NPC). There was no particular tendency observed in susceptibility for drugs among the strains studied in relation to the 0-group of Escherichia coli and the year when the respective strain was isolated.