A grandfather has had both of his legs amputated after being bitten by a pet dog and contracting sepsis—a month after the same animal scratched his brother-in-law, leaving him with a fatal infection.

In the bustling heart of Tokyo, a bronze statue stands as a tribute to Hachiko, an Akita dog whose unwavering devotion to his owner made him a global icon of loyalty. For nearly a decade, Hachiko ...