The incidences of growth-agglutination (GA) and IgG-GA antibodies against Erysipelothrix rhusiopathiae were examined on sera collected from 12 slaughter pigs with chronic swine erysipelas (group A), 46 clinically healthy pigs which were housed with infected pigs on 11 farms (group B), and 188 clinically healthy slaughter pigs from 18 farms where chronic erysipelas had never been previously detected at slaughter (group C). In group A, GA and IgG-GA antibodies were very high titer, ranging from 1: 256 to ≥ 1: 2, 560 and from 1: 128 to 1: 1, 280, respectively. There were no differences in the GA titer and positive rates of IgG-GA (1: 4 or above) between groups B and C, namely the former were 1: 25.1 and 1: 22.4 of geometric mean (GM), and the latter were 39.1% and 44.7%. The positive rate of IgG-GA on each farm of groups B and C varied from 0 to 100%. Eight pigs (4.3%) of group C possessed high IgG-GAtiters (1: 32 or more) suggesting that they might be infected naturally in the housing. This would mean that development of serum antibody is not enough due to retained maternal antibody derived from the vaccination.Erysipelothrix rhusiopathiae was isolated from 3 samples (2.7%) of a mixture of feces and bedding on 2 farms (4.2%). Serotypes of these isolates were 2, 5 and 7.
The attenuated KB/VT strain of Getah virus was established from the parental 2078 strain by the serial passages and plaque clonings in Vero cell cultures at the low temperature of 30°C. The KB/VT strain induced no clinical signs in suckling mice by intracerebral inoculation with the virus. The KB/VT strain formed clear plaques on cultures of hamster lung cell line (HAL) as did other virulent Getah virus strains, but the plaque size was obviously small and distinguishable from that of the parental 2078 strain. This character was stable even after 5 consecutive passages of the KB/VT strain in HAL cell cultures at 37°C. The KB/VT strain showed antigenicity similar to these of the other virulent strains by cross neutralization test. All these findings suggested that the KB/VT strain might have so attenuated as to be available as a candidate strain for a live virus vaccine against Getah virus infection in swine.
A total of 124 strains of Staphylococcusaureus isolated from cow's milk were tested for antibioticsusceptibility and β-lactamase production. The results are summarized as follows: 1. The MIC90 of benzylpenicillin, cloxacillin, cefalonium, cefuroxime, streptomycin, kanamycin, erythromycin and oxytetracycline against the isolates ranged from 0.14μg/ml to 7.69 μg/ml. 2. The β-lactamase production was found in 47 isolates (39.8%), but methicillin-resistant S. aureus was not isolated. 3. The antibiotic-sensitivity of the β-lactamase producing strains was influenced by the growth temperature or the pH of the growth medium.
From January to February in 1988 on a farm in Yamaguchi Prefecture, twelve piglets, one to two months old, showed nervous signs accompanied with fever and died. Furthermore in March on this farm, four piglets showed the same signs. Necropsy of one of diseased piglets revealed hemorrhage in meninges of the cerebrum, cerebellum and medulla oblongata, and remarkable hyperaemia with pleuritis. Many noduler lesions, white or grayish white in color, were also observed in the lungs. In histopathological examinations, the purulent meningitis in various parts of the brain, and edema and necrosis of the lungs were noticed. Actinobacillus pleuropneumoniae serovar 2 was isolated in pure culture from the brain, lungs, heart and kidneys of this diseased piglet. From these results, the present case was diagnosed as purulent meningitis caused by A. pleuropneumoniae serovar 2. This case seems to be very rare in Japan.
An ear-tag made of synthetic resin containing 15%(w/w) permethrin was attached to each ear of 416 dairy cattle which were put out to pastures of three ranches, D, H, and K, in Tochigi Prefecture. The tags remained attached for about six months from April to October, 1988. The tags were collected from some of the cattle once or twice monthly during the period and weighed. Quantity of permethrin remaining in tags was also determined. The results obtained are summarized as follows: 1. Weight of the ear-tag and content of permethrin in the tags steadily decreased at a high rate during the first four months, thereafter the decreasing rate became lower. Loss of permethrin in the tags was about 900 mg (the daily mean, 5.5 mg) during the whole testing period. 2. The quantity of permethrin loss per tag per day was calculated to be 8.925 mg the first month, 4.065 mg the fourth month and 0.825 mg the sixth month by the regression analysis.
The author found a tumor in the thoracic part of the esophagus in a 7-year-old female Yorkshire terrier. The dog vomited due to passage disturbance of food as the main sign, along with remarkable loss of weight. The tumor showed extensive growth in the thoracic part of the esophagus, extending from the inlet of the thorax to the basis cordis. By thoracicoraparotomy, the developmental site of the tumor in the esophagus was dilated on the both sides and the tumor grew on the sternal side compressing the trachea, resulting in remarkable deformity and stenosis. The dog died owing to dyspnea under the operation. The esophageal tumor excised post mortem had a cauliflower like appearance and was histologically diagnosed as fibrosarcoma. It infiltrated into the muscularis externa and tumor cells often showed mitosis and atypia. The tumor was clinically considered malignant becaus of its rapid growth, but no metastasis could be detected in any other organs examined.
A dead wild racoon dog was examined pathologically. Grossly hepatization of the lungs was seen. Histologically, eosinophilic cytoplasmic inclusion bodies were found in the cytoplasm of splenic reticuloendothelial cells, surface epithelial cells of the stomach, transitional epithelial cells of the bladder, and the bronchiolar epithelial cells. Electron microscopically, crystalline-arrayed nucleocapsids were observed in the splenic reticuloendothelial cells and transitional epithelial cells of the bladder. From these findings, the death of the racoon dog may be attributed to the growth of canine distemper virus in cells of the lungs, spleen, stomach, bladder and bronchia.
Seven strains of bacteria, isolated from two piglets and two cows suffering from dermatitis or arthritis and presumed to belong to the genus Staphylococcus, were comparatively examined by the quantitative fluorometric DNA-DNA hybridization method in microplates, conventional biochemical tests and a commercial identification kit microbe (API STAPH). The DNA-DNA hybridization method is a genetic microbe identification method. In this experiment, the intensity of DNA-DNA hybridization between DNA from a test isolate and DNA from each of 26 reference species of the genus Staphylococcus which were fixed in microdilution wells was measured fluorometrically. The isolate was identified as a species which showed the strongest hybridization. All of the seven strains were identified definitely as S. hyicus by the quantitative fluorometric DNA-DNA hybridization method. In contrast, conventional biochemical tests identified three out of the seven strains as S. hyicus, but could not allow determination of species classification of the remaining four. While also, five of the seven strains assigned were identified as S. hyicus while the remaining two were assigned to several species other than S.hyicus following assessment with the commercial identification kit. The DNA-DNA hybridization method required only four hours to give results after picking up a colony. Thus, it was shown that the method is rapid and accurate, and therefore, useful for identification of S. hyicus, particularly for bacteria having atypical phenotypic characteristics.
Parasitological and pathological examinations were performed on 104 pigs with emphysema along the lung margin due to lung worm infestation at a slaughter house in Ibaraki Prefecture from July 1989 to March 1990. Lung lesions containing lung worms were most prevalent in the right diaphragmatic lobes (81.7%), and common in the left diaphragmatic lobes (76.0%). Most of the pigs (75.0%) had emphysematous changes at the margin in one or two pulmonary lobes and lung worm infestation was evaluated to be mild in the pigs examined. Average number of lung worm was 4.1 per bronchiole, and the female to male ratio was 3: 1. All the lung worms obtained in this series were identified as Metastrongylus apri. Histopathological examination revealed prominent eosinophilic infiltrations and hyperplastic lymphoid follicles in the bronchial mucosa.