The Hokkaido brown bear is the largest terrestrial mammal in the Hokkaido ecosystems and now inhabits almost all forests in Hokkaido, Japan. These bears have evolved through a unique shift from carnivorous to omnivorous feeding habits, which are of interest to their ecology. However, human-bear conflicts, such as human injury and crop or livestock damage, have become a serious concern, which requires ecological research for its mitigation. The hibernation behavior of bears has unique characteristics that differ from those of other small hibernators, including minimal decrease in body temperature. Interestingly, they show resistance to muscle atrophy and bone loss during prolonged periods of immobility. This review provides an overview of ecological and physiological studies on bears from One Health perspective, focusing on ecology, human-bear conflict, infectious diseases, and hibernating physiology and its application to human health.

In the present study, intestinal specimens were collected from layer chickens at a poultry slaughterhouse and used to evaluate infection with Eimeria species. Intestinal contents were extracted separately from the rectum (from the duodenum to rectum) and cecum and used for analyses. Using flotation detection methods, the number of eimerian oocysts per gram was higher in the cecum than rectum. Polymerase chain reaction analysis also detected a greater abundance of Eimeria species in the cecum than the rectum. These results suggest that analysis of cecal contents could be more useful for detecting and identifying Eimeria species.

We examined the antimicrobial resistance of 1,493 Escherichia coli isolates from 440 swine fecal samples (211 and 229 samples were obtained from the sow and fattening groups, respectively) on ten farms and analyzed the association between the antimicrobial resistance rate and the annual antimicrobial usage at the farm level adjusted by the daily defined dose in Japan. For most antimicrobial agents, the rate of resistance was greater on farms with higher levels of antimicrobial use, suggesting that the amount of the corresponding antimicrobial class used at the farm level may have affected the resistance rates. Some antimicrobial resistance was positively associated with the use of the corresponding or structurally related antimicrobial agents: resistance to tetracycline in the sow group and resistance to chloramphenicol, streptomycin, kanamycin, sulfonamide-trimethoprim, and nalidixic acid in the fattening group. In addition, for many antimicrobial-resistant strains, an association was found with the use of single or multiple antimicrobial classes other than the corresponding class: resistance to ampicillin and kanamycin in the sow group and resistance to ampicillin, cefazolin, cefoxitin, cefotaxime, tetracycline, chloramphenicol, streptomycin, kanamycin, gentamicin and nalidixic acid in the fattening group. In the case of the association with the noncorresponding class, most of the E. coli isolates were multidrug resistant, suggesting that there is a high possibility of coselection on farms and that reducing the use of multiple antimicrobial agents may be effective at decreasing antimicrobial resistance.

Highly pathogenic avian influenza (HPAI) is a contagious disease of poultry characterized by high avian mortality and devastating economic losses. Between October 2022 and April 2023 (in the 2022–23 season), there were 84 cases of HPAI on poultry farms in 26 prefectures of Japan, resulting in the culling of approximately 17.7 million birds. This study examined the economic impact of HPAI outbreaks on poultry farms in Japan during the 2022–23 season. Farm direct economic losses and burden to the national and prefectural governments from compensation were estimated. Data were obtained from epidemiological survey reports prepared by the Ministry of Agriculture, Forestry and Fisheries, prefecture websites, and through direct contacts. Losses incurred by the national government as compensation granted to infected farms for birds culled and eggs discarded as contaminated goods were estimated. Economic losses for poultry farms located in movement and shipment restriction zones were assumed to be reduced sales and increased farm management costs and shared equally by the national government and infected prefectures. Economic losses on infected farms were estimated from the outbreak until recovery of production. Total economic losses incurred by the national government, infected prefectures, and infected poultry farms were estimated at approximately 16.9 billion, 183.5 million, and 14.2 billion Japanese yen (USD 126.6 million, 1.4 million, and 106.4 million), respectively. Although data are limited, the quantification of economic losses due to HPAI in this study could contribute to future evidence-based policy making.

PRRS (Porcine Reproductive and Respiratory Syndrome) is a costly disease in the global pig industry. In 2021, Nisseiken Co., Ltd. in Japan launched a PRRS-killed vaccine, PRRS-ME, but its effectiveness on reducing the death rate under field conditions remained unassessed. A longitudinal study on a PRRS-positive farm in Japan (July 2019–July 2022) evaluated its effect on death rates. Piglets on a PRRS-negative farrowing farm were vaccinated at 3 and 8 weeks of age in March 2021. The vaccinated piglets were introduced to the finisher farm, where a PRRS outbreak occurred. Vaccination coverage was not associated with the death rates of growers but was negatively associated with those of finishers. The predicted reduction in the death rate of finishers associated with complete vaccination coverage was 56.8%.

Probiotics have been suggested as a treatment for canine atopic dermatitis, a form of dermatopathy common in dogs. This systematic review and meta-analysis aimed to evaluate the effect of probiotics as an adjuvant in treating canine atopic dermatitis in vivo studies with dogs. The study was conducted following the PRISMA guidelines. Only clinical studies in dogs with atopic dermatitis that received intervention with probiotics were selected, being just original articles in English from the last 5 years (2019–2023). A total of 293 articles were obtained, and after the inclusion criteria, only 5 articles were eligible and included in the systematic review and meta-analysis. The 5 studies used different probiotics at concentrations of 10⁸ to 10¹⁰CFU/mL/g, 3 studies with oral administration for 12 weeks, and 2 studies with topical use for 4 weeks. The meta-analysis results show that probiotics did not present significant effects against atopic dermatitis by evaluating the CADESI-4 scale (P=0.08) and the PVAS scale (P=0.85). Furthermore, regarding the method of administration of probiotics (oral or topical), the meta-analysis showed that there were also no significant results when the disease index was evaluated using CADESI-4 (P=0.07) or PVAS (P=0.92). We concluded that, even without significant effects, all trials showed a reduction in CADESI-4 and PVAS scores, reflecting a reduction in the severity of atopic dermatitis in dogs that used probiotics as treatment adjuvants.

A 4-month-old, British Shorthair kitten was referred to our institute for evaluation of a heart murmur. Thoracic radiography and echocardiography revealed narrowing of the right pulmonary artery, accompanied by right atrial dilation and right ventricular hypertrophy. The systolic flow velocity across the stenotic lesion was 6.15 m/sec, with a pressure gradient of 151.42 mmHg. Computed tomography confirmed right pulmonary coarctation with concurrent interruption of the left pulmonary artery. Balloon angioplasty was performed, reducing the systolic flow velocity from 6.15 m/sec to 2.79 m/sec and relieving right ventricular pressure overload. One year later, thoracic radiography revealed left lung collapse and right lung hyperinflation; however, the patient remained asymptomatic. At 33 months post-diagnosis, the patient continued to thrive without any clinical signs.

Anticoagulants are commonly used to treat venous thrombosis. Rivaroxaban, a direct factor Xa inhibitor, is widely used in veterinary medicine to prevent and treat thromboembolism. It has been used to manage portal vein thrombosis (PVT) in humans. As the incidence of PVT with chronic hepatitis (CH) is low in dogs, treatment methods have not been fully established. This case report describes the treatment of a 9-year-old male American cocker spaniel with CH and ascites, possibly due to concurrent PVT, using rivaroxaban. During treatment with rivaroxaban and diuretics, the patient showed improvement in portal hypertension, ascites, and edema. Herein, we report the first case of using rivaroxaban for the management of PVT with CH (treated with glucocorticoids) in a dog.

Anesthesia management in experimental animals is essential for animal welfare and data reproducibility. In Japan, medetomidine–midazolam–butorphanol (MMB) is commonly used due to ketamine restrictions. We developed medetomidine–remimazolam–butorphanol (MRB) by replacing midazolam with remimazolam for faster metabolism and recovery. This study compared MMB and MRB administered intraperitoneally (i.p.) or subcutaneously (s.c.) in C57BL/6J mice of both sexes. Induction and recovery were assessed using immobilization, loss of righting reflex, and return of righting reflex. MRB i.p. produced the fastest induction and recovery with relatively low variability, suggesting potential utility for brief procedures. In contrast, s.c. administration resulted in consistent onset and recovery profiles for both agents, which may be advantageous for routine experimental use.

An 11-year-old male French bulldog presented with incidental cystic lesions by the pulmonary CT. CT revealed two cysts in the right caudal lobe of the lung that were suspicious for emphysematous lesions. These cysts were divided into an air layer and a soft tissue-like layer. Dynamic computed tomography (DCT) of cysts revealed undulating motion in the soft tissue-like layer. The dog’s rearing environment included brackish water, and it was evident that the dog had been eating brackish water crabs from the river. The dog was diagnosed with paragonimiasis. This DCT imaging revealed movement of live worms inside the cysts. This study is the first report that DCT may be useful for differentiating paragonimiasis from other pulmonary lesions.

Fasciolosis, a parasitic disease caused by Fasciola flukes, leads to economic losses in livestock. These flukes require freshwater snails, such as the genera Orientogalba and Galba as intermediate hosts, made snail distribution monitoring essential for disease surveillance and prevention. A survey conducted in Aomori prefecture from spring 2022 to summer 2023 identified Orientogalba snails and Galba snails in 49 rice paddies. Molecular analysis of 233 cytochrome c oxidase subunit 1 partial sequences classified Orientogalba into O. hokkaidoensis and O. ollula. Orientogalba hokkaidoensis was widely distributed across Aomori prefecture. Most Galba snails were identified as Galba pacifica. Additionally, some Lymnaea schirazensis-like snails were detected. These findings provide fundamental data on freshwater snails in Aomori, aiding fasciolosis control.

This report presents the case of a 22-year-old male squirrel monkey with primary seminal vesicle adenocarcinoma (PSVA). The animal presented with hematuria and emaciation. Pathological autopsy of the seminal vesicle tumor revealed an irregularly shaped, white, solid mass showing ductal/papillary and solid patterns and periodic acid-Schiff-positive mucus in the duct. The vesicle was dilated by blood. Tumor cells showed cytoplasmic eosinophilic granules, and a transition to tumor tissue was observed. Immunohistochemical analysis indicated that all tumor cells were cytokeratin-negative; only ductal/papillary cells were vimentin-positive. Other organs were tumor free. PSVA was diagnosed based on the site of tumor origin and histopathology, similar to PSVA in laboratory rodents. This study reports a case of PSVA in a new-world monkey.

A 3-year-old neutered male mixed-breed cat was presented with right urinary tract obstruction caused by a urolith and severe atrophy of the left kidney. In the next year and a half, chronic kidney disease (CKD) progressed, and several masses were identified in the extremities, along with an ulcer on the tongue. Histologically, the extremity masses consisted of calcium deposits separated by fibrovascular septa, and the tongue ulcer showed severe neutrophilic infiltration with pervasive calcium deposition. These lesions were diagnosed as calcinosis circumscripta (CCs). Concurrently, multifocal mineralization of the aorta and of small- to medium-sized arteries in several organs indicated widespread vascular calcification. Both extremity and vascular lesions were likely secondary to the excessive calcium-phosphate product caused by CKD. Although CCs in either the extremities or tongue has been reported in cats, this case is notable for the presence of CCs in both extremities and tongue with systemic vascular calcification.

An 11-year-old Bichon Frise presented with a right cervical mass. Computed tomography revealed a thyroid mass without significant lymphadenopathy; however, the caudal portion of the ipsilateral retropharyngeal lymph node exhibited marked hyperattenuation on pre-contrast images. Histopathology of this lymph node confirmed the presence of metastasis from thyroid adenocarcinoma. The caudal portion of the lymph node displayed dense tumor cells with abundant sodium/iodide symporter-positive cells. The observed hyperattenuation of the lymph node was presumed to result from iodide deposition associated with the metastasis of the thyroid tumor. This case suggests that even in the absence of lymph node enlargement, hyperattenuating lymph nodes should raise suspicion for metastasis in dogs with thyroid tumors. However, as this is a single case, further studies are needed to determine the broader applicability of this finding.

The spread of antimicrobial-resistant bacteria in natural environments is a global concern. In the present study, we investigated the distribution of cefotaxime-resistant Aeromonas hydrophila in the gills and intestines of freshwater fish. Bacteria carrying the ampH, bla_VEB-3, and cphA1 genes were more frequently isolated from the gills, and most were assigned to ST1068. A genetically related strain was identified not only in fish but also in the river water. These results suggest that fish may be a valuable tool for monitoring environmental contamination caused by antimicrobial-resistant bacteria.

This study evaluated the effects of different prostaglandin F_2α (PG) regimens on luteolysis, estrous behavior, and ovulation timing in dairy heifers using an automated activity monitoring (AAM) system. Eight days after presynchronized ovulation (designated as Day 0), twenty-seven heifers were assigned to one of three PG regimens, administered 24 hr apart: a single standard PG dose of 500 µg followed by saline (one standard dose, OSD, n=8), two low PG doses of 375 µg and 250 µg (two low doses, TLD-1.5, n=8), or two PG doses of 250 µg each (TLD-1, n=8). All heifers experienced complete luteolysis and ovulation after PG treatments, however, heifers in the TLD-1.5 and TLD-1 groups exhibited delayed progesterone (P₄) decline, prolonged luteolysis, later estrus onset, and lower peak value of the estrous alarm (PA) than those in OSD. Despite these variations, the interval from estrus to ovulation remained stable, confirming AAM’s reliability for predicting suitable artificial insemination (AI) timing. The delayed luteolytic patterns induced by each regimen affected estrous expressions, as the serum P₄ concentration on Day 1 was positively correlated to the timing of highest estradiol (E₂) as well as ovulation but negatively correlated to PA. The ability of AAM to consistently predict ovulation, regardless of variations in luteolysis, ensures its practical value in AI programs. These findings highlighted the importance of optimizing PG regimens while reinforcing the role of AAM in reproductive management.

Understanding the subcellular localization and regulatory mechanisms of DNA repair proteins is critical for elucidating the mechanisms of genotoxicity. Localization of DNA repair proteins is highly spatiotemporally regulated, and their dysregulation causes of various diseases, including cancer. Dysregulation also modulates cytotoxicity and genotoxicity caused by medical radiation and environmental mutagens. Non-homologous end joining (NHEJ) is the most important but error-prone pathway in DNA double-strand break (DSB) repair. NHEJ is initiated by binding of the Ku70/Ku80 heterodimer to the DSB. If a DSB is not repaired correctly, cells may die or undergo mutations. We have previously shown that EYFP-canine Ku70 localizes to the nuclei of canine cells. However, the mechanism through which canine Ku70 localizes to the nucleus remains unclear. In this study, we provide the first experimental evidence that canine Ku70 localizes to the nucleus and that its predicted nuclear localization signal is bound by the nuclear pore-targeting complex, importin-α/β. In addition, the transfected EYFP-canine Ku70 localized to the nucleus in human, hamster, and mouse cells, suggesting that canine Ku70 translocates and localizes to the nucleus via a common mechanism conserved among these four species. We also found that Ku80 is essential for the accumulation of canine Ku70 in DSBs. These findings provide fundamental information for understanding the regulatory mechanisms of Ku70 and the molecular mechanisms underlying the cytotoxicity and genotoxicity induced by DSBs in dogs.

Although most coronaviruses are thought to have their origins in bats, there is little information on whether bats are still susceptible to the currently prevalent coronaviruses. We generated a continuous cell line from a kidney of Pipistrellus abramus (P. abramus) by serial passaging of the cells, which could be proliferated for more than 80 passages without any immortalization process. We found that porcine epidemic diarrhea virus (PEDV) and bovine coronavirus (BCoV) were able to infect and generate progeny viruses in P. abramus-derived cells in the presence of trypsin, although the replication efficiency was quite low. The findings suggest that P. abramus could be susceptible to PEDV and BCoV and may play a potential role as a transmitter of the viruses.

Reproduction of endangered wildlife, including elasmobranchs, is a fundamental mission of modern aquariums. Captive breeding programs necessitate artificial insemination to better utilize the limited stock in each facility. A cownose ray (Rhinoptera javanica) was successfully inseminated producing a live offspring. The semen was collected under chemical restraint, extended with a custom-made solution and kept chilled at 6°C for 24 hr. The quality of the semen was assessed at collection and just prior to insemination, noting color, volume, subjective sperm motility, sperm viability and concentration. Intrauterine insemination was carried out under chemical restraint. The monitoring of pregnancy was performed by serial ultrasound scans of the fetus assessing gilling and heartbeat. A healthy female pup was born after a gestation of 429 days (61 weeks and 2 days). Genetic microsatellite analysis confirmed that the pup was not a product of parthenogenesis and identified the donor male as the sire. This is the first report of a successful artificial insemination in an aplacental viviparous ray, suggesting these techniques can be applied to other species in this clade.

In this study, we examined filarial infections in Japanese black bears around the Lake Towada area from 2020 to 2022. Microfilariae were observed in 81.6% of blood smears. Consistent with previous findings in Iwate Prefecture, polymerase chain reaction (PCR) analysis detected Dirofilaria ursi (89.7%) and Mansonella sp. (66.7%) in extracted blood DNA. The body size of D. ursi microfilariae matched previous reports, whereas Mansonella sp. microfilariae were smaller than those of D. ursi and other known species. Although we attempted to identify Mansonella sp. adult filariae using PCR, all recovered adults were D. ursi; no adult Mansonella sp. were detected. Further studies are needed to better identify and understand both the adult filariae and microfilariae of Mansonella sp. in Japanese black bears.

A 15-year and 7-month-old male European wolf kept in a zoological park since birth, became emaciated and died. At necropsy, the gastric and mesenteric lymph nodes were enlarged, and perforation was observed in the stomach. Histopathologically, diffuse proliferation of lymphoid tumor cells was observed in the lymph nodes, stomach, lungs, kidneys and spleen. The tumor cells were immunopositive for CD3, CD8, granzyme B, and TIA-1. These results suggest that the tumor cells exhibited a cytotoxic T-cell immunophenotype. Clonal rearrangement of the T-cell receptor gene was identified using standard canine primers. This is the first report on histopathological and immunohistochemical characteristics of T-cell lymphoma in a wolf, highlighting the potential effectiveness of a canine clonality analysis for diagnosing lymphoma in wolves.

Iriomote cats (Prionailurus bengalensis iriomotensis) are a critically endangered, wild felid subspecies, for which blood and urine data are lacking. We evaluated hematology and serum biochemistry (n=69) and urinalysis (n=56) values for sex differences, and differences versus a reference range in domestic cats (Felis catus). Males showed higher red blood cell count and total cholesterol, and females showed higher platelet count. Iriomote cats showed values above the reference range in domestic cats in some parameters (aspartate aminotransferase, glucose, blood urea nitrogen, creatinine phosphokinase, and lactate dehydrogenase). Urinalysis revealed white blood cells and marginal protein levels, which were likely due to strenuous activity and stress. The study provides valuable data on health indicators for this subspecies.