To isolateStaphylococcus aureus (S. aureus) and coagulase-negative staphylococci (CNS), examinations were made of mammary-gland secretions (MGS) from healthy and mastitic dairy cows at different stages of lactation. In the MGS of healthy mammary glands, throughout both lactating and nonlactating periods, S. aureusand CNS were detected at high levels near those observed in chronically infected mammary glands. MGSs were examined also for incidence and concentration of such staphylococcal enterotoxins (SEs) as SEA, SEB, SEC, SED, and SEE and for toxic shock syndrome toxin-1 (TSST-1). These toxins were detected at levels of nearly 50% in cultures of bothS. aureusand CNS. In the MGSs, incidences and amounts of SEC, though of neither the other SEs nor TSST-1, correlated well with degree of mammary-gland inflammation. These results strongly suggest that SEC may participate as a causal agent in subclinical staphylococcal mammary-gland infection causing apparent mastitis.

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Prevalence of the complement-fixation antibody againstMycoplasma hyopneumoniaewas determined in 18, 995 serum samples collected from sows and fattening pigs of various ages in Japan between 1995 and 1997. At least 1 pig in 504 (96.0%) of 525 conventional herds sampled had the minimal titer of 1: 4 againstM. hyopneumoniae. Of 18, 995 serum samples, 8, 324 (43.8%) demonstrated an antibody titer of 1: 4 or higher. The seropositive rate (titer≥1: 4) in fattening pigs was 20.1%(GM titer 1: 19.8) before the age of 1 month. After 1 month of age, it decreased. Thereafter the seropositive rates increased gradually to reach 63.9%(GM titer 1: 18.1) at 6 months of age. Seropositive rates in sows decreased with increasing numbers of farrowing. Little seasonal or regional difference in positive rates was observed. These results suggest thatM. hyopneumoniaeinfection is still widespread among pigs in Japan.

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Necropsy of 2 racing pigeons that had suffered from sluggishness, loss of appetite, and diarrhea revealed severe peritonitis. Microscopic examination showed atrophy of the lymphoid follicles with severe depletion of lymphocytes and reticular-cell replacement in the bursa of Fabricius. Abundant botryoid basophilic intracytoplasmic inclusion bodies were found in reticular cells and in macrophages in the bursal follicle. In addition, chlamydial intracytoplasmic inclusion bodies were found in macrophages infiltrating the polyserositic lesions. Electronmicroscopical examination of basophilic inclusion bodies in the bursa of Fabricius revealed numerous virus particles resembling circovirus. They were about 15 nm in diameter and demonstrated a paracrystalline arrangement. Our findings confirm these cases as concomitant infection with a circovirus and with Chlamydia psittaci, suggesting the existence of a pigeon circovirus in Japan.

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We compared the effects of infusions of Ringer's lactate (LR) and acetate (AR) solutions, on acid-base balance and hepatic energy metabolism during 40 min of hepatic inflow occlusion and 30 min of reperfusion in dogs. A slightly milder acidosis was observed in the group receiving AR, compared with the group receiving LR. After 40 min of occlusions in the LR group, ketone body concentrations in arterial and venous blood markedly decreased to a comparable level, indicating no uptake of ketone bodies in peripheral tissues. In contrast, in the group given AR, ketone body concentrations did not decrease during the inflow occlusion. Both the arterial concentration and arterio-venous concentration gradients were maintained, indicating sufficient supply and utilization of ketone bodies in the peripheral tissues. Moreover, the renal-venous concentration of ketone bodies was slightly higher than the arterial concentration, indicating renal ketogenesis during hepatic inflow occlusion in dogs receiving AR infusions. The hepatic energy levels (ATP+1/2ADP) in the AR group were significantly higher than in the LR group after 30 min of reperfusion. Due to the improved acid-base balance and sufficient ketone body supply to peripheral tissues, the metabolic burden of the liver after release of occlusion was considered to be smaller in the AR group. AR administration during hepatic ischemia is recommended.

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A 9-year-old dachshund was brought to our clinic suffering from alopecia, widely distributed pigmentation, and bilateral cryptorchidism with high concentration of urinary estrogen. A mass (17×15×13 cm) surgically resected from the abdominal cavity was submitted to histopathological examination and diagnosed as seminoma. After surgery, the dog was afflicted by serious anemia characterized by spherocytes and reticulocytes, increased leukocyte count, and the appearance of platelets and lysemia. These findings suggest that the anemia may be immune-mediated hemolytic anemia.

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Japanese slaughterhouses certifying meat exports to the United States are obliged to monitorSalmonellain accordance with partially revised American regulations for sanitary examinations. The Food Safety and Inspection Service (FSIS) of the U.S. Department of Agriculture prescribes a monitoring detection sensitivity of 97% and a specificity of more than 96%. In this study, we compared standard methods of analysis in Food Safety Regulations (FHT method) with the FSIS method for meat samples inoculated withSalmonella. In samples inoculated with H₂S positiveSalmonella, results obtained by the FHT and the FSIS method were almost the same. In samples inoculated with H₂S negativeSalmonella, however, detection rates obtained with the FHT method were clearly lower than those obtained with the FSIS method.

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