Health authorities have traced the latest COVID-19 outbreak in China to a local primary school in Fujian province. Initial investigation into the case suggests that the disease may have been brought to the country by one of the students' fathers, who had traveled from Singapore.

Authorities said the father had also tested positive for the virus last week and they are now working to trace back his steps. All of the students and faculty members of the school have been ordered to take COVID-19 tests after more than 100 new cases were detected over the last four days.

The latest outbreak in Fujian comes just a month after health authorities contained an outbreak in Nanjing. The city of Putian is reportedly one of the hardest hit by the virus.

Health authorities said they have traced the infections to a primary school in the city, which they said could be the source of the latest outbreak. The father of one of the students is believed to be the first one to contract the virus. He tested positive for COVID-19 about 38 days since he returned from a trip to Singapore.

According to state-run media, the father had served a mandatory 21-day quarantine when he arrived. He reportedly tested negative in all of his tests, which included nine nucleic acid and serologic tests. Authorities have not ruled out the possibility that he may have contracted the virus locally as the coronavirus is not known to have such as long incubation period.

Fujian officials have already taken precautionary measures to avoid any further spread of the virus. Schools in the province have been ordered closed and people leaving Putian city are now required to present a negative COVID-19 test taken no less than 48 hours.

Non-essential establishments in the city, including cinemas, libraries, and museums, in surrounding areas, have also been told to suspend indoor activities. Restaurants have also been ordered to limit their operating hours while enforcing strict social distancing measures. Nearby cities, such as Quanzhou and Xiamen, have also imposed similar restrictions to mitigate the spread of the disease. On Monday, Xiamen authorities reported 32 new COVID-19 cases, all of which were traced back to Putian city.