Spheroids are three-dimensional cell colonies, and spheroid culture enables cell culture in an environment that resembles an in vivo environment more closely than adhesion cell culture. In the field of veterinary medicine, there have been no reports on the application of spheroid culture for the isolation of viruses. We verified the possibility of using this culture technique for virus isolation by comparing the results obtained from the isolation of viruses in adherent culture and spheroid culture, using five bovine stool samples that tested positive for rotavirus C (RVC) based on the detection of a specific gene. As a result, RVC was successfully isolated from three of the five samples by spheroid culture method. In addition, it was possible to isolate the virus at a higher rate when it was inoculated before spheroid formation. Therefore, inoculation of the specimen before spheroid formation was considered important for implementing this method. There are only two cases of RVC isolation reported in Japan, and improvement of the virus isolation rate can be expected by using spheroid cultures. Moreover, this spheroid culture method can be beneficial for studying virus species that are difficult to isolate.

Forty-day-old weaning piglets at a farm in Kagoshima developed watery diarrhea and died in February 2019. Two piglets with diarrhea were euthanized. A large number of trophozoites of Trichomonas spp. were histologically observed in the crypt lumina of the ileum, colon, and cecum in these piglets. Numerous parasites also invaded the mucosal epithelium and lamina propria mucosae in one piglet. Genomic DNA was purified from sections of the small and large intestine, and PCR amplified products were sequenced. Tritrichomonas foetus was identified based on sequencing results. Ultrastructurally, three anterior flagella and one posterior flagellum were observed in the parasite. Numbers of caspase-3 and TUNEL-positive cells increased in crypt epithelium. Bacteriologically, non-hemolytic Escherichia coli was isolated from the piglet intestinal content. These results suggested that T. foetus has the ability to invade mucosa and induce apoptosis, and is associated with the pathogenesis of diarrhea.

A 10-year-old mixed breed dog presented with hematuria and lethargy. Clinical examination confirmed a mass in the proximal lumen of the left ureter causing unilateral ureteral obstruction and hydronephrosis. Intrarenal pressure was reduced through placement of a nephrostomy tube. After stabilization of the patient, a biopsy was taken via laparotomy. Tissue samples were obtained via traumatic catheterization of the left ureter via the left kidney, without a ureterotomy. The traumatic catheterization technique successfully removed enough of the intraluminal mass that the ureteral obstruction was resolved. Histopathological examination suggested a possible tumor of transitional cell origin. However, a definitive diagnosis was not made from the histopathology. Piroxicam was administered orally for 659 days, and the patient remained clinically stable during this period. Serial ultrasonographic examinations revealed no signs of recurrence of the obstruction in the left ureter, therefore, piroxicam was discontinued. After 965 days, the patient presented with hematuria and lethargy. Ultrasonographic examination revealed re-obstruction of the left ureter from the intraluminal mass. Because the tumor progressed slowly, we speculated that it was most likely benign. Surgical debulking was performed via left ureterotomy under laparotomy. Histopathological examination confirmed transitional cell papilloma. The dog remained clinically stable without recurrence of the ureteral mass one year after surgery. Because some ureteral tumors in dogs have been reported as benign lesions, not only nephrouretectomy on the affected side but also debulking surgery could be a diagnostic and therapeutic option.