TAIPEI (Taiwan News) — The Centers for Disease Control found five chefs and five patrons tested positive for norovirus at a hot pot restaurant in Yilan.

Norovirus is a highly transmissible illness spread through a fecal-oral route, causing vomiting and diarrhea within 12-48 hours. It is often confused with food poisoning due to the rapid onset of symptoms and cluster infections, per CNA.

The hotpot chain restaurant opened for trial operations in Yilan’s Luodong on March 15. A week later, 63 people associated with the restaurant felt unwell, according to Yilan County Public Health Bureau.

CDC Deputy Director-General Tseng Shu-huai (曾淑慧) on Tuesday said 17 samples were collected from the hot pot restaurant, of which 10 tested positive for norovirus, including five restaurant staff. No other pathogens have been detected from the restaurant so far.

Tseng said the epidemiological investigation found that five restaurant staff reported no symptoms. In addition to human samples, environmental and food samples were collected. Questionnaires were issued to customers to understand what ingredients were consumed.

Tseng said further testing for other pathogens is needed for an epidemiological assessment.

For the diarrhea epidemic, CDC Epidemic Intelligence Center Director Kuo Hung-wei (郭宏偉) said that from March 16 to 22, 186,708 people visited emergency departments for diarrhea, a decrease of 12.7% from 213,782 people the previous week.

Kuo said in the past four weeks, 176 diarrhea clusters were reported in Taiwan. The largest number of cases were associated with the catering and hotel industry, with 107 positive pathogen tests, of which 104 detected norovirus, accounting for 97.2% of cases.