In 2017, one dairy farm initiated measures for preventing the spread of enzootic bovine leukosis (EBL). Subsequently, bovine leukosis virus (BLV) antibody prevalence on this farm decreased from 11.8% to 2.4% over 3 years. The prevalence of the DRB3*0902 allele, one of the resistance-associated alleles, was 15.4% on the farm, significantly higher than that of the dairy cattle surveyed in this study. In addition, the segregation of seropositive cattle from the seronegatives was deemed to be an effective method for preventing horizontal transmission of BLV. Further, replacement of seropositives was predictably effective at decreasing antibody prevalence on the farm.

In this study we examined the distribution of bee virus species among wild arthropods captured at three apiaries in Gifu prefecture using PCR and sequencing methods. The results showed that wild hornets (n=23) were positive for Israeli acute paralysis virus (IAPV, 87%) and Deformed wing virus (DWV, 56%), and the wild grasshoppers (n=5) were positive for IAPV (40%). Phylogenetic analyses showed that IAPV and DWV derived from these wild arthropods formed a cluster with those from reared honeybees. Our results indicated that wild hornets possess bee virus species and may be related to transmission cycles in apiaries in Japan.

Sixty-four canine cases of transitional cell carcinoma treated with complete cystectomy were retrospectively analyzed for signalment, pathology findings, treatment modality and outcome. The mean age of onset (10.7 ± 2.2 years) and sex ratio (40 females and 24 males; 63.5% vs. 36.5%) were consistent with those previously reported. Mixed-breed dogs, shetland sheepdogs, beagles and possibly long-haired miniature dachshunds were overrepresented. The survival time ranged from 5 to 3,089 days with a median survival time of 205 days. The survival time differed significantly among the three groups of dogs with tumor invasion into the lamina propria, muscular layer and serosa of the bladder wall. These findings suggest that survival of 6 months or longer can be expected after a complete cystectomy and that this approach may be an effective treatment option for canine transitional cell carcinoma.

This study discusses four cases of T-cell tumors we found in aged Japanese Black cattle in Hokkaido Japan with remarkable splenomegaly, dark red bone marrow of the sternum and vertebra in gross examination, which showed erythrophagocytosis in histological examination. Similar cases have been widely found at meat inspection sites all over Japan and diagnosed as atypical bovine leukemia due to the macroscopic differences from enzootic bovine leukemia. In this study, we examined four of these cases using histological, immunohistochemical and PCR methods. A HE stain showed that, in two of the four cases, neoplastic cells contained clear large eosinophilic granules in the cytoplasm. Immunohistochemistry revealed that, in all four cases, neoplastic cells had Granzyme B positive granules in the cytoplasm, including two cases in which granules were not observed in the HE stain. The PCR test found all four cases negative for bovine leukemia virus. These findings in the four cases we examined suggest that the cases should be diagnosed as T-cell granular lymphocytic leukemia/lymphomas and should not be attributed to bovine leukemia virus.