Hong Kong health authorities have launched an investigation into a norovirus outbreak involving 20 students and one teacher who developed gastroenteritis symptoms during a study tour in mainland China.
The 21 patients reported symptoms of vomiting, diarrhoea, and fever last Friday, a day after they arrived in Zhaoqing, a city in Guangdong Province, for a three-day exchange trip, the Centre for Health Protection (CHP) said on Sunday.
According to the CHP, a total of 135 teachers and students from a secondary school in Tsing Yi took part in the study tour. Local media reported that the school was Po Leung Kuk Lo Kit Sing (1983) College.
Eighteen infected individuals sought medical attention in Zhaoqing, eight of whom tested positive for norovirus. All patients are in a stable condition and have been discharged, the disease prevention and control agency said.
A preliminary probe by the CHP found that the patients had not consumed any common food items apart from the group meals. There was also no acute gastroenteritis outbreak in the school recently.
“After analysis of the onset time of the cases, at this stage, the CHP could not preliminarily rule out that the cases were infected by consuming contaminated food,” a statement from the CHP read.
The local health agency said it would continue to conduct epidemiological investigations, including collecting and testing stool specimens from the cases.
Latest case
It was the latest case of gastroenteritis outbreaks reported this month involving students and teachers who visited mainland China.
On March 11, the CHP reported that 52 teachers and students from three secondary schools developed acute gastroenteritis symptoms after travelling to Shaoguan, Guangdong Province. The number of patients rose to 55, the CHP said on March 17.
The schools affected were Sha Tin Government Secondary School, Lok Sin Tong Ku Chiu Man Secondary School, and TWGHs Chen Zao Men College.
On March 17, the CHP reported another cluster involving six students from a Kwun Tong secondary school who showed gastroenteritis symptoms after visiting Xiamen, Fujian Province, between March 13 and 15. According to local media, the school was FDBWA Szeto Ho Secondary School.
On Sunday, the CHP also warned that apart from mainland China, gastroenteritis outbreaks were reported in popular travel destinations such as Japan, Singapore, and Taiwan. Most of the outbreaks were caused by norovirus, which can be transmitted through eating contaminated food, the CHP said.
The number of norovirus infections also rose locally since the end of last December and “remained at a relatively high level in recent months,” it said.
“Members of the public should remain vigilant and maintain personal, environmental and food hygiene at all times to minimise the risk of being infected while travelling,” the CHP said.
