Testing by the Pasteur Institute in Ho Chi Minh City found Salmonella in 25 of 36 samples taken from patients who fell ill after eating at the Hong Ngoc 37 outlet in Dong Thap Province, the local ward authority said on June 20.
As of the afternoon of June 19, 290 people had been hospitalized across several facilities in the Mekong Delta and in Ho Chi Minh City. Twenty-eight have been discharged, and the others are in stable condition.
The outbreak emerged on June 16, when patients began arriving with abdominal pain, vomiting, diarrhea, fever, fatigue and numbness in the hands. Case numbers climbed from 22 that first day to 93, then past 200 within 48 hours.
An epidemiological report found that every patient had eaten banh mi from the same shop, on Ly Thuong Kiet street in My Tho Town.
Hong Ngoc, a chain that advertises more than 100 outlets across the Mekong Delta, has been linked to a mass poisoning three times, and the previous two were traced to the same source.
