2026 Volume 79 Issue 2 Pages e1-e8
A Japanese Black calf exhibited an inability to stand at 4 days of age and died at 8 days of age due to urinary obstruction. We examined the cause of death. The post-mortem revealed a urachal remnant, where the umbilical vein and urachus were connected to the navel through an open duct. Furthermore, extensive accumulation of fibrinous exudates was observed in the umbilical vein, urethra, and bladder. Pathological research using microscopy revealed infarcted nephritis accompanied by suppuration and necrosis of the bladder. Cultured tissues from the calf's liver, kidney, bladder, ureters, and urachus showed the predominant presence of Escherichia coli, suggesting that the calf was infected with E. coli via the umbilical cord, leading to a fatal outcome due to ExPEC infection. Gene identification by PCR revealed that the ExPEC possessed four iron acquisition genes (iutA, fyuA, irp1, and irp2) linked to its pathogenicity.
