Marvel the Dachsund was drinking water from a puddle next to a Pembroke Pines shopping center when he was found.
The small dog was emaciated at 5.2 pounds and smelled like "death," said Pets in Distress volunteer Kelly Lecain.
"I didn't even know the condition when I got there," said Lecain, who responded to the rescue call. "It's just unthinkable."
Marvel had no collar, tags or microchip when he was found on Thursday of last week, Lecain said. He had abscesses in his mouth and lesions in the back of his throat. His bones could be seen protruding under his skin.
It is hard to determine Marvel's age because of the mouth infection.
Lecain said involuntary tears poured down her face when she met Marvel.
"At that time I said, I don't know if I can keep doing this. It was just so heartbreaking," she said. "He is the third dog in six weeks we have rescued in this condition."
Pets in Distress is a rescue group that fosters animals until they are well enough to be adopted. LeCain said right now the organization is overwhelmed with abandoned animals – needing more money and people to volunteer to care for dogs until they get permanent homes.
In six days, Marvel has gained one pound and 12 ounces after spending some time on IVs and eating a pureed mixture of carbs.
Despite his dangerous condition, Lecain said Marvel is on the long road to recovery.
"I sat down on the grass with him and I told him, 'You know buddy, it's going to be alright now,'" she said. "And his tail started wagging and it hasn't stopped since."
Lecain said the organization is asking for aid in Marvel's recovery. To make a donation, visit petsindistress.org.
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