A serological survey of the porcine reproductive and respiratory syndrome virus (PRRSV) employing enzymelinked immunosorbent assay (ELISA) was conducted on 5, 535 samples collected at 207 pig farms in Japan from August 1998 to March 1999. Some of the pig farms from which samples were collected used a modified livevirus vaccine against PRRS. The pig farms demonstrated high prevalences (66.2%, 137/207) of the antibody. Pig-serum samples demonstrated a positive rate of 34.5%(1, 910/5, 535). These results indicate that the PRRSV is widely prevalent among farms and pigs in Japan.
Investigations of parasitic fauna in the digestive tracts of 53aigamoducks (Japanese crossbreed of mallards and domestic ducks) from 8 farms in 6 Japanese prefectures conducted between June 1996 and January 1997 showed the following.Eimeria anatisoocysts were detected in ducks 23, 27, and 65 days old from a farm in Kanagawa Prefecture.Capillariasp. eggs were detected in ducks aged 118 days from farms in Akita and 65 days Kanagawa Prefectures andC. anatiseggs in ducks aged 82 days from Kagoshima Prefecture.Pseudechinostomum incoronatumandEchinostomasp. were detected in 2 of 20 ducks from farm C in Kanagawa Prefecture and in 1 of 5 ducks from farm B in Kanagawa Prefecture.Apatemonsp. was observed in 12 of 29 ducks in Kanagawa Prefecture (farm B: 4/5, farm C: 7/20, farm D: 1/4), in 1 of 5 ducks in Kyoto and in 2 of 6 in Kagoshima Prefecture.Fimbriariasp. was detected in 7 of 20 ducks in Kanagawa Prefecture (farm B: 1/5, farm C: 4/20 and farm D: 2/4). In Kagoshima Prefecture, Capillaria anatiswas observed in 4 of 6 ducks andC. nyrocinarumin 2 of 6 ducks. This paper is the first report onEimeria anatisandCapillaria nyrocinarumin aigamo ducks in Japan.
Successively in 1997 and 1998, the Ibaraki disease affected 9 head of cattle on 9 dairy farms in Fukuoka Prefecture. Although the diseased cattle had received no vaccine against the Ibaraki disease in 1998, the anti-Ibaraki virus (IBAV) antibody was detected in all of them. IBAV was isolated from washed red blood cells of one affected animal. Six sera from abnormally delivered fetuses and 3 precolostral sera from weak calves contained the anti-IBAV antibody. The cross-neutralization test and PCR-RFLP identified isolates obtained in 1997-98as the same type of IBAV. These findings plus the limiting of Ibaraki disease incidences to Fukuoka Prefecture, Kyushu, suggest that the virus, widespread in 1997, overwintered within the prefecture to cause the same epidemic disease in 1998.
A serological survey conducted in Okayama Prefecture from August to October 1998 revealed that 89.9% of sentinel calves were positive for Akabane virus (AKV) antibodies and 46.4% were positive for Aino virus antibodies. A total of 136 cases of congenital abnormalities caused by AKV (102 case) and AIV or both (34 cases) was observed from early September 1998. Nested PRC detected the S RNA genomes of both viruses in serum samples from sentinel calves in late August and September. From late September into early December, The S RNA genome of AKV was detected in aborted or stillborn fetuses and in a 25-day-old calf with astasia. AIV was isolated from the blood plasma of a sentinel calf in late September 1998. Congenital abnormality caused by fetal infection with AKLV occurred at from 2 to 9 months gestation and congenital abnormality caused by fetal infection with AIV at from 3 to 6 months gestation. The nested PCR proved effective in epidemiological survey and in rapid diagnosis of AKV and AIV infections.
Pathohistological and immunohistochemcial investigations of 2 premature fetuses (fetal ages 113 and 129 days) aborted by the same cow within 6 months on a dairy farm showed multifocal necrosis invaded by microglia that were negative for the GFAP (glial fibrillary acidic protein) antigen and slightly positive for the CD (clusters of differentiation) 68 antigen. Immunohistochemcial staining revealed a proliferation of tachyzoites positive for the antibody against theNeospora caninumNC-1 strain in necrotic lesions in the liver, kidneys, and allantoic stalk. Necrotic lesions in the allantoic stalk were thought to be one of the causes of early abortion.
The characteristics and parturient conditions of singleton Holstein nuclear transfer calves derived from embryo cells were compared with those of singleton calves produced by artificial insemination and invivoderived embryo transfer. Observation of variation in birth weight among nuclear transfer calves from the same embryo origin showed nuclear transfer calves to be on an average significantly heavier than calves produced by artificial insemination and invivo-derived embryo transfer (51.9±7.4 vs. 45.2±5.5 and 45.3±5.6 kg, P<0.05). The gestation period of nuclear transfer calves was significantly longer than that of artificial insemination calves (283.4±5.4 vs. 280.8±5.8 days, P<0.05). Parturient difficulties and the dystocia rate of nuclear transfer calves were significantly higher than in control groups (30.0 vs. 12.7 and 13.6%, P<0.05); and posterior presentation, stillbirth, oversizing and fetlock knuckling were frequently observed. We believe the high occurrence rate of oversized calves accounts for a high rate of dystocia and stillbirths in nuclear transfer calves. Furthermore, their postnatal survival rate is low.
Percutaneous portography was used in place of conventional intraoperative mesenteric portography to diagnose portosystemic shunt in 3 dogs. One diagnosis was performed by means of percutaneous jejunal arterial portography; the remaining 2 by means of retrograde caudal venography. For percutanous jejunal arterial portography, a coaxial catheter was introduced into the jejunal artery. Iopamidol was the contrast agent in a dose of 1.0 ml/kg, X-ray photographs were taken after injction of the contrast agent. For retrograde caudal ventography, an occlusion balloon catheter was inserted from the external jugular vein to the caudal vena cava. In this case, sodium iotalamate (1.25ml/kg) was the contrast agent. X-ray photographs were taken after its injection. As a result of these procedures, diagnosis of the quality of portograms was good enough to make a definite diagnosis of portosystemic shunt in all 3 cases.
Pathological examination was performed on prostatic tumors in 2 dogs (case 1: male golden retriever, 9 years old; case 2: male mongrel, 11 years old). The tumor in case 1 consisted of proliferated round to ellipsoid cells resembling prostatic epithelium arranged in sheets with many mitoses. The tumor in case 2 consisted of atypical epithelial cells demonstrating intra-acinar proliferation. In immunohistochemical examination using the antibody against human prostate specific antigen tumor cells in case 1 were negative, whereas those in case 2 were positive. Electron microscopy of case 1 showed large, atypical nuclei of tumor cells. Numbers of cellular organelles varied among tumor cells. No acini were present. In case 2, tumor cells formed small acini with slightly atypical nuclei, free ribosomes, and secretory granules. Desmosomes were noted in both cases. On the basis of these findings, case 1 was diagnosed as syncytial prostatic carcinoma and case 2 as intra-alveolar proliferative prostatic carcinoma.
In May 1997, upon inspection at a meat-processing plant, about 8% of the broilers were discarded because of gelatinous exudates in subcutaneous tissues. Pathological examinations were subsequently performed on breast meats from 8 (group A) and thigh meats from an additional 8 (group B) of the birds with these exudates. Breast meats from 10 birds (group C) without apparent macroscopic lesions were used as controls. Histologically, all the 16 birds showed appearance of the synovial bursae by its dilation and proliferation of granulation tissue. Dermal granulomas were dectected in 3 birds in group A and 2 birds in group B. Thickening of the skin and subcutis too was observed in groups A and B.
Such tetanus symptoms as rigor of the limbs were detected in 2 deadrabbits that had been bred at 2 different elementary schools in Tokyo. A total of 11 strains of Clostridium tetani were isolated from abscesses on the rabbits and from soil samples collected from the breeding areas. The biological characteristics of the strains were identified, and the polymerase chain reaction method detected the tetanospasmin gene. The strains were classified into 4 groups according to genetic analysisby pulsed field gel electrophoresis (PFGE).