HELSINKI, Oct. 2 (Xinhua) -- Swedish health authorities have launched an extensive contact-tracing effort after a listeria outbreak linked to a restaurant in central Stockholm sickened around 20 people, with several developing sepsis, public broadcaster SVT reported Thursday.
Four patients developed sepsis, but none required intensive care, according to the Stockholm regional health authority. Reported symptoms include high fever, diarrhea and vomiting.
Officials said about 400 guests who dined at the restaurant between Sept. 23 and 27 had been contacted for monitoring, while at least 80 suspected food poisoning complaints have been filed.
Infectious disease specialist Viktor Dahl said the number of cases is "unusually high," and the incubation period shorter than normal.
Minister for Social Affairs and Public Health Jakob Forssmed said the government had been briefed and that "extensive work is being carried out across the country to track and assist patients."
The restaurant, now temporarily closed, plans to reopen on Oct. 7.
