Pseudomonas aeruginosa (PA) was examined for sensitivity in vitro to four antibiotics, two sulfonamides, and nitrofuran. A total of 21 strains were isolated from one focus each of 21 dogs in Tokyo over a period from 1967 to 1968 and used for the investigation. To determine the minimum growth-inhibiting concentration (MIC) of each drug, broth-cultures were dropped on agar plates containing various concentrations of the respective drug. The inoculated plates were incubated at 37°C for 24 hours. The results obtained are summarized as follows. All the strains tested were sensitive to polymyxin B, gentamycin, and colistin sulfate. These antibiotics had an MIC of 12.5mcg/ml. or less. No strains tested were sensitive to any other drug.
A survey was conducted to determine the presence of hemagglutination- inhibiting (HI) and neutralizing (NT) antibodies against Newcastle disease virus in the serum of human beings that were engaged in vaccine production. A total of 156 human sera were collected from 64 persons exposed to virulent virus by contact (group A), 36 persons exposed to low virulent (B1 strain) virus (group B), and 56 persons notexposed to virus (group C), which served as controls. As a result, 12.9, 12.6, and 4.0 per cent of the tested were found to have the mean HI titer in groups A, B, and C, respectively. The mean NT titers were 0.73, 0.87, and 0.15 in groups A, B, and C, respectively It was assumed that an HI titer of 1: 16 or over and an NT titer of 1.0 or over might indicate a positive reaction. Then HI: 59.3% and NT: 45.3% of group A, HI: 38.8% and NT: 46.9% of group B, and HI: 0% and NT: 5.3% of group C were found to give a positive test. There was no difference in antibody titer of human serum between exposure to the virulent virus and that to the low virulent virus. The more frequently human beings were exposed to the virus, the higher antibody titer they obtained. those who were constantly exposed to the virus showed no clinical signs while working. These results suggest that exposure to Newcastle disease virus may lead to latent infection in human beings.
In the city and neighboring areas, of Kagoshima, swine sera were collected mainly over a seven-month period beginning in April every year from 1966 to 1968. They were examined for virus-neutralizing (VN) and hemagglutination-inhibiting (HI) antibodies against Japanese B encephalitis (JBE) virus. In addition, similar antibody survys were conducted on sera of small numbers of horses, cattle, and rabbits in 1966 and 1967. Furthermore, viral isolation was carried out from the blood of experimental breeding swine, rabbits, and mosquitoes collected during the epizootic season. The results obtained are as follows. 1) In all the years, VN and HI antibodies turned positive in all the animals. JBE virus was recovered from swine blood and mosquitoes when the epizootic season came. These results suggested that inapparent infection of JBE virus might have broken out among animals in the southern Kyushu district over a period from early June to middle July, though variable with year. Furthermore, there was a close relationship between atmospheric temperature and the beginning of prevalence. 2) In 1967, antibody turned positive irregularly in the pigs of the same group and a JBE virus epizootic spread very slowly. In addition, VN and HI antibody titers were generaly lower in the sera collected in 1967 than those in any other year, and turned quickly to negativity. This result indicates that there is a fairly remarkable difference in epizootiological aspect between the occurrence in 1967 and that in 1966 and 1968. 3) Viral isolation was carried out from swine, rabbits, and mosquitoes in ESK-1 cell culture. As a result, three strains of JBE virus were recovered from swine blood, and two strains from mosquitoes over a period from 1966 to 1968. Cytopathogenesis was observed in an ESK-1 cell culture infected with all the isolates. Exceptionally, the Taniyama S-2 strain isolated from swine blood in 1967 had no hemagglutinating activity in the liquid phase of infected ESK-1 cell culture. It was suggested that there might be a difference in property between the Taniyama S-2 strain and any other strain.