Mary Adhiambo said her two sons had heard the two-week old girl, named Angel by nurses, crying near their house in a Nairobi suburb, the BBC reported.
"I followed them outside and looked around our compound and a nearby plot," Adhiambo said. "I saw my dog, which I have had for five years, lying protectively with her puppy besides the soiled baby lying in a torn black cloth."
A hospital spokeswoman said doctors believe the baby was abandoned two days before she was discovered. Local residents said she was likely left in a nearby forest and found by the dog, who then carried her in the bag she was left in from the forest to the house.
The spokeswoman said doctors found maggots in Angel's umbilical cord, but she was responding well to treatment. Hospital staff said members of the public have donated baby clothes and diapers.