Tabanus trigeminus flying over and swarming on 4 seropositive cattle were captured and their heads and blood clots in the abdomen were examined for bovine leukemia virus (BLV). Approximately 120 insects were blood sucking for 2 h on a fine day. Syncytium formation was induced on CC81 cell inoculated with lymphocytes from the heads of the insects but not with those from the sucking blood clots of the abdomen. After rearing together with the 4 seropositive cattle mentioned above in a pasture for 6 months, all the 6 seronegative cattle became seropositive.
Fifty three of 60 (88.3%) adult rabbits suddenly died within a period of 9 days at a tourist farm in Shizuoka Prefecture in March 1995. Three dead cases were histopathologically examined, revealing lesions characteristic of rabbit hemorrhagic disease (RHD) comprising necrotic hepatitis and disseminated intravascular coagulations in the lungs and kidneys. By immunostaining with antibody against RHD virus viral antigen was demonstrated within hepatocytes. Electron microscopy showed the presence of calicivirus-like particles in the cytoplasm of necrotic hepatocytes. The disease was experimentally reproduced in rabbits inoculated with liver homogenate from the affected cases, and calicivirus particles were purified from the infected liver homogenate. The present cases were the second outbreak of RHD in Japan following the cases in Hokkaido in 1994.
Ninety one foals were necropsied and examined for Rhodococcus equi infection at Animal Clinic Center of Nosai Hidaka, Hidaka Livestock Hygiene Service Center, and School of Veterinary Medicine and Animal Sciences, Kitasato University from 1992 to 1996. Forty-nine of 91 cases had been clinically diagnosed as R. equi pneumonia, while the remaining 42 as non-R. equi pneumonia (14 foals), arthritis (6 foals), and others (22 foals). Pathologically, 89 cases were shown to have suppurative pneumonia with abscesses, and the remaining 2 cases had intestinal involvement without pulmonary lesions. Bacteriologically, virulent R. equi was isolated from lesions of all the 91 foals. Based on the pathology and bacteriology, 91 cases were classified into 4 disease types: pneumonia type (40 cases; suppurative bronchopneumonia), enteritis type (2 cases; ulcerative enteritis associated with suppurative lymphadenitis of the intestine), mixed type (23 cases; pneumonia, enteritis, and intestinal lymphadenitis), and transitional type (26 cases; pneumonia and intestinal lymphadenitis).
Sixty nine of 91 foals pathologically and bacteriologically diagnosed as Rhodococcus equi infection at Animal Clinic Center of Nosai Hidaka, Hidaka Livestock Hygiene Service Center, and Kitasato University School of Veterinary Medicine and Animal Sciences from 1992 to 1996, were analyzed for age distributions atthe first clinical exmamination and death. About 88% of the foals showed clinical signs within 2 months of age peaking at 40 days, and the mean age at the initial clinical examination was 53.4±21.7 days. About 77% died within 80 days of age peaking at 50 to 60 days, and the mean age at death was 77.7±35.4 days. Foals with mixed and enteritis types of disease and those born in March and April showed slightly advanced ages at the first clinical examination and death, but difference was not significant. There was no bias with breeds and sex of foals.
The preventive effect and clinical safety of chlormadinone acetate (CMA) on oestrus was assessed in Siam queens after subcutaneous implantation in silicon rubber for 12 months. Oestrus was completely inhibited in those treated with more than 2.5mg/kg of CMA and recurred 3 to 16 weeks after removal of the implant.
Experimentally infected cats were examined for hemagglutination-inhibition IgM-antibodies to feline panleukopenia virus (FPLV). The antibodies were detected in all cases showing clinical signs and leukopenia at 5 to 10 days postinfection (PI) and disappeared around 14 days PI with clinical recovery. FPLV-hemagglutininsin were detected in feces as early as 3 days PI and disappeared earlier than the serum antibodies turned negative.
Ticks were collected from 38 (12 species) of 686 migratory birds and 5 (3 species) of 44 birds examined in Fukui Prefecture in autumn of 1995 and in spring of 1996, respectively. They consisted of Ixodes columnae (1 case), I. persulcatus (5), I. turdus (10), I. sp. LT (2), Haemaphysalis flava (60) and H. longicornis (4). Borrelia spirochetes were isolated by BSK culture from nymphal H. flava feeding on Turdus pallidus (2 cases), larval H. flava feeding on T. cardis (1) and nymphal I. persulcatus feeding on T. pallidus (1).