Correct. There were several stories out of Viet Nam where American POWs allowed maggots to eat the gangrenous flesh from their untreated wounds, then used their own urine to rinse off the "cleansed" area.
Must've looked terrible, but they survived.
Maggots are still used in the medical community because they only eat the necrotic flesh allowing healing to take place. What was sad was the poor man ending up in this situation.