On July 8 the ship Deborah from Jeremie, Haiti, arrived at the fort below the city to undergo inspection and serve quarantine. The Deborah was a Philadelphia ship with a crew of 37 and 58 passengers. In his answers to the routine questions from the Health Inspectors, Captain Edward Yard attributed five deaths on the voyage to dysentery and claimed that at Jeremie people were "healthy on shore, but sickly in the harbor."
While she stood quarantine six people from the ship were sent to the marine hospital. "A French black girl" died. Two seamen recovered. When two doctors sent by the Health Committee to certify the vessel healthy investigated on the 16th, they found two of the other sick seamen on the way to recovery. Their diseases did not appear contagious. Those who remained on board appeared healthy, and the ship very clean. Two ventilators had been used on it.
The captain argued that the few deaths among white adults on the voyage were due to intemperance or lack of seasoning. On the 18th the doctors allowed the ship with its passengers and cargo of coffee, cocoa and sugar to move up to the city to unload at a wharf near Race Street. The doctors were concerned by reports that people had visited the ship. The Health Committee published a warning that ships visited while under quarantine would be required to serve an additional quarantine of five days.
On July 20 Dr. Samuel Griffitts was called to treat Thomas Wharton who had a store near Race Street. A veteran of the epidemics of '93 and '97, Griffitts recognized yellow fever and promptly bled his patient and administered enough mercury to bring on a salivation. Griffitts suspected that the fever was imported by a ship. He noted that Wharton's store was near the wharf where the Deborah was tied up.
On the 25th the Deborah left the Race Street wharf to be taken to Kensington for repairs. Griffitts treated and cured another store keeper near the Race Street wharf, and then, on the 30th, had a fever patient below Walnut Street. The Deborah entered into that case too. Alexander Philips reportedly confessed that he had gone by boat down to the Deborah as she rode quarantine and brought up a sick man from the ship. Also on the 30th a carpenter in Kensington who had been working on the Deborah died of yellow fever.
A mob reportedly tried to force the ship back into the river but Captain Yard had armed men protect it.
By August 6 there enough reported cases of yellow fever to prompt 17 members of the College of Physicians to recommend that Water Street between Walnut and Spruce be evacuated and ships tied up there be relocated. The doctors counted at least 30 sick with the fever along the water front. In its public communications, the College did not blame the Deborah for importing the fever, but its private conviction was well
The story spread that Dr. Griffitts, a usually mild manner Quaker, confronted the brother of Captain Yard and blamed the Deborah for bringing the fever. The man "doubled his fist" and said his brother would "knock down anybody that said so." Griffitts stood his ground and asked where the man was who had come ashore sick. The captain's brother admitted that he was dead. Dr. William Currie began interviewing the Deborah's crew, getting admissions that it had left a port in the midst of a yellow fever epidemic.