A days-old puppy found abandoned at a bus stop has died of an infection, and now the B.C. SPCA is urging pet owners to be more responsible with their animals to avoid another "sickening" tragedy.

Little Peanut was just a day old when she was discovered in a Puma sneaker box under a bus-stop bench on 207th Avenue in Maple Ridge on Friday. The black and white mixed-breed newborn was rushed to the Dewdney Animal Hospital, where she was treated for hypothermia and seizures.

Veterinary workers thought the little dog was out of the woods, but foster father and Maple Ridge SPCA branch manager Mark Vosper told ctvbc.ca that Peanut died during the night on Monday.

"It was a huge disappointment when she passed," he said.

A necropsy revealed that Peanut was suffering from a serious infection near her umbilical vein, suggesting that the umbilical cord had been cut too close to her body. Vosper said the puppy also appeared to be low on colostrum, the protein and antibody-rich milk produced by new mothers.

"Obviously she didn't have a very good start to life," Vosper said.

The SPCA's animal cruelty investigators are still searching for more information on who left the tiny dog wrapped in a beige fleece blanket inside the women's size-7.5 shoe box.

Vosper was livid in his condemnation of whoever abandoned Peanut.

"They should be so ashamed. It's sickening that somebody could treat any animal in this regard," he said.

"To treat a newborn like this, it's just unforgivable."

The SPCA is reminding dog owners try to find new homes for unwanted animals and contact local animal shelters if they can't instead of leaving puppies like Peanut out in the cold.

"We have a night emergency patrol, and so if somebody contacts the SPCA, we can make arrangements at any time for animals to be collected or dropped off," Vosper said.

"Just leaving a puppy, doing nothing, just abandoning an animal outside -- that's not an option."

Anyone with more information about Peanut's owners is asked to call the Maple Ridge SPCA.