Bovine salmonellosis has been increasing in recent years. Salmonella enterica serovar Dublin (SD) is among the causative agents, and when SD infection occurs, bacterial shedding in feces is intermittent. SD is often not isolated from infected animals, which makes it difficult to accurately assess the degree of contamination of farms. In addition, a considerable amount of time and labor is necessary to isolate bacteria, which hinders rapid responses to control outbreaks. Aiming to make it possible to rapidly assess farm contamination and improve hygiene management, we developed an indirect ELISA system (SD-ELISA) to detect antibodies against SD lipopolysaccharides (LPS) in this study. To verify the usefulness of SD-ELISA, field surveys were conducted on cattle farms where SD outbreaks had occurred. Results indicated that 48 of 129 head of cattle tested positive using SD-ELISA, including one from which SD was isolated. These findings suggest that SD-ELISA is useful in the evaluation of the contamination levels of farms. There is the potential for contamination assessments using SD-ELISA in addition to comprehensive determinations based on clinical symptoms and epidemiological information to contribute to the rapid and effective control of outbreaks on farms.

As of May 2025, there are 465 HACCP-certified farms, but this has remained flat since 2022. To identify the causes for this, three questionnaire surveys were conducted asking 30 farms that had implemented HACCP to respond, and 13, 16, and 20 farms responded to the three different surveys. Additionally, data on the safety and productivity of products from dairy cattle farm, beef cattle farm, and pig farm operations (two farms each, a total of six farms) were analyzed following HACCP implementation. The survey results showed that the responses of 11 of the 13 farms indicated that digital tools were necessary for HACCP operations, and 5 of 16 farms reported increased productivity after HACCP implementation (6 out of 12 farms that introduced digital tools). Furthermore, no deviations from critical control point (CCP) management standards were observed at any cooperating farm, ensuring safety. However, of the 15 hygiene management targets for the six farms, five farms met 11 of them at least once. To promote HACCP adoption, it is considered necessary to establish a phased evaluation framework aimed at improving productivity and to develop and utilize effective digital tools.

In this study, we compared three classical swine fever (CSF) outbreaks that occurred in Ibaraki Prefecture (outbreaks 1, 2, and 3 were at non-vaccinated, 10 days post-vaccination, and approximately 90 days post-vaccination, respectively). In particular, we analyzed the characteristics of outbreak 3, which occurred in a fattening pig group approximately 90 days after primary vaccination. In outbreaks 1 and 2, hemorrhagic lesions, high viral loads, and transmission to other barns were observed. In contrast, in outbreak 3 there were no hemorrhagic lesions, high Ct values, negative fluorescent antibody assay, and no CSF virus isolation, and also no viral genome were detected in tha enviroment. Additionally, no horizontal transmission to other barns was observed, and pigs with high neutralizing antibody titers were confined to the affected pig barn. Moreover, the principal lesions observed in the necropsied pigs were pneumonia and pericarditis, indicating that CSF was unlikely to have been the primary cause of death. Taken together, these findings suggest that CSF vaccination may have contributed to the suppression of pathological changes, reduction of viral replication, elimination of viruses capable of intracellular proliferation, and the prevention of environmental contamination and horizontal transmission within the farm.

In October 2023, a breeding Japanese Black cow underwent an abortion at a farm in Yamaguchi Prefecture. Histopathological examination revealed diffuse degeneration, atrophy and necrosis of hepatocytes, and no other noteworthy findings in the organs examined. Viral examination revealed the Epizootic Hemorrhagic Disease Virus (EHDV) serogroup 6 gene was detected in the major organs of the fetus, and EHDV-6 was not isolated in a static culture but was isolated in a rotary culture of BHK-21 cells from the fetal liver. Phylogenetic analysis of the segment 3 partial genome sequence of the isolated virus confirmed that it was classified into the Eastern group, which is found in East Asia and Australia, similar to EHDV previously detected in Japan. This is the first report of EHDV-6 isolation from an aborted bovine fetus in Japan.

We analyzed the pathological characteristics of one case of malignant pheochromocytoma and five cases of pheochromocytoma in cattle detected at the Kanagawa Prefectural Meat Inspection Station. All cases were elderly Japanese Black and Holstein cattle. In the malignant pheochromocytoma case, tumors were found in the left adrenal gland, the posterior vena cava, and both lungs. In the pheochromocytoma cases, tumors were found in one or both adrenal glands. Microscopically, tumor cells were arranged in alveolar or trabecular pattern separated from each other by a connective tissue stroma with capillaries. The neoplastic cells of the pheochromocytoma were more markedly pleomorphic than those of the malignant pheochromocytoma. Immunostaining showed that neoplastic cells were positive for chromogranin-A and synaptophysin, and the Ki-67 positivity rate was lower in the malignant pheochromocytoma than in the pheochromocytoma. In this study, cases of metastasis without significant pleomorphism or proliferation were identified, suggesting that it is difficult to distinguish between benign and malignant tumors in cattle, similar to tumors in humans.

This study explored the feasibility of using fluid dripping from frozen clams that was obtained as a sample for detecting hepatitis A virus (HAV). When the ultracentrifugation method specified in the national notification was used with the dripping fluid, the pellet solidified into a gel, making nucleic acid extraction difficult. In contrast, when the dripping fluid was pretreated with amylase, the gel did not form and HAV was successfully detected. HAV was also detected in the second sample of dripping fluid obtained after refreezing and rethawing, and some samples showed higher viral copy numbers than in the first sample of dripping fluid. This suggests that rapid temperature changes may influence the amount of virus released, although the behavior varied among samples and no consistent trend was observed. Conventional bivalve testing requires excision of the digestive gland and removal of unwanted tissues, which increases the risk of introducing PCR inhibitors. In contrast, dripping fluid is easy to collect and contains no tissue fragments, indicating its potential utility as a supplementary sample for HAV source investigation.